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Old 06-21-2013, 12:54 PM   #1
troyemcm
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Premiere XL Struck by Lightning

I have a Premiere XL and it was struck by lightning (I believe) last week. I was getting absolutely nothing out of it when I plugged it in, no lights, etc. So I thought I would try replacing the power supply. Now the only activity I get is the hard drive spins and the Ethernet jack lights light up.

I looked all over for a fuse but can't find one. Has anyone had a similar experience? I called Tivo and all they offer is to replace it for $ 150.

Thanks in advance for any advice.
Troy

Last edited by troyemcm : 06-21-2013 at 12:55 PM. Reason: Typo
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Old 06-21-2013, 01:09 PM   #2
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A lightning strike could have fried the whole mobo. If that's the case the TiVo is toast. If it has lifetime I'd take TiVo up on their offer and this time buy a UPS or high quality power strip to plug it into.
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Old 06-22-2013, 06:35 AM   #3
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Sorry to hear that - if it was a lightning strike, the unit is probably toast.

If you are using OTA, you should make sure your antenna is grounded, and that the antenna cable has an in-line lightning surge protector (which must also be grounded). Installation codes vary by state, but this is essential to avoid damage to equipment when you are using an antenna.
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Old 06-22-2013, 04:29 PM   #4
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...If you are using OTA, you should make sure your antenna is grounded, and that the antenna cable has an in-line lightning surge protector (which must also be grounded). Installation codes vary by state, but this is essential to avoid damage to equipment when you are using an antenna.
I've had my external antenna grounded since I installed it 10 years ago. Coax runs through power conditioner/surge protector. Always pays to be smart...
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Old 06-22-2013, 05:28 PM   #5
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It really IS essential that your cable and/or your antenna grounds are very good, remain that way the whole run, and that your connections are tight.

I got bored once, and was looking at the layout of the two manufacturers that TiVo uses for their power supplies, and both of them shunt the power supply's built-in surge protection to the case, making the cable/antenna inputs the one true isolated ground.

I also found out that if the power supply is not screwed down to the case, that nearly all the protection is lost, except a surge between Neutral & Line, because they use the case to complete some of the protection circuits, on the PS itself.

The Premiere has the FIRST power supply I've ever seen that has open/incomplete circuits if all the screws closest to the case side aren't in place... Given the way it could short out if not secured, or insulated, I'd never apply power without those three screws (minimum) in place, unlike how I usually just *carefully* try things before I go putting screws in.
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Old 06-23-2013, 08:53 AM   #6
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I looked all over for a fuse but can't find one.
Fuses typically do not not trip due to a surge. Surges are done in microseconds. Fuses take milliseconds to trip.

Damage occurs when a surge enters on one wire. And leaves on another. So what would be a path destructively through a Tivo? Generally, only one part in that path fails. Replace that one part and the Tivo would probably work. Problem is that most have no idea how to identify that part. Since most surge damage leaves no visual indication. So many assume all motherboard parts are destroyed.

Others discussed earthing an antenna. However if any one incoming wire is not earthed to the same 'single point earth ground', then the earthed antenna can even be a reason for damage. Critical is earthing to a 'single point earth ground'.

In a parallel example, lightning strikes a tree. Some 20 feet from the tree is a cow. The cow is also killed by a direct strike. Why? Lightning is a connection from a cloud to earthborne charges maybe 5 miles distant. A shortest path from the cloud is 3 miles to the tree. And four miles through earth to those charges. Also in that path was the cow. A surge current went up its hind legs. And down its fore legs. Cow killed because it did not have a single point earthing connection.

Same applies to Tivo damage. If AC electric and antenna have different grounds, then the Tivo would be in an electric current path that enters via an antenna ground. And exits via AC electric ground.

A high quality power strip or UPS does not even claim to avert that damage. That damage is averted by connecting all incoming wires directly (hardwired) to single point ground. Or by making the next best thing - a 'whole house' protector from that incoming wire to earth.

If any wire enters without a low impedance (ie 'less than 10 foot') connection to earth (either by wire or protector), then future damage should be expected. Today it was a Tivo. What may be damaged tomorrow? Furnace? Refrigerator? GFCIs? Dimmer switches? Washing machine? Learn from the damage. Neither fuses nor magic boxes provide that protection. How did lightning connect to earth destructively (and maybe blow out only one component) via your Tivo?
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Old 06-23-2013, 07:20 PM   #7
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<whole bunch of "stuff" removed>
Question: How do you attain the type of ground you go on-and-on about, when no TiVo uses a three-pronged (grounded, as opposed to just using neutral) power cable?

Answer: Via the cable/antenna input ground, which is the next best thing, as long as all the connections are good, all the way to ground/earth.

As much as I've love to drive in a several foot long, heavy gage, copper ground rod near all my TiVo installations, and run a copper wire right to each case, it's not practical.

I rely on good grounds, tight connections, one whole home surge suppressor, multiple battery backup units with surge protection, and protection strips where there is no need (or it's impractical) for a UPS. I don't use the available coax surge protectors, which you see on most modern UPS & surge protection power strips, as they tend to wind up being the source of many cable signal issues, and typically aren't rated for 1GHz, or higher, frequencies. When using good splitters, and proper grounds, I don't lose any sleep over some random possibility of a transient surge coming through the signal wire.

Your post is understandable, for me, since I know the point you are trying to make. However, I think it would confuse most, and leave some just joking over involving a cow in the matter.
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Old 06-23-2013, 08:51 PM   #8
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Question: How do you attain the type of ground you go on-and-on about, when no TiVo uses a three-pronged (grounded, as opposed to just using neutral) power cable?
First, do not earth the Tivo. That only makes a Tivo the better and destructive path to earth. Earth a surge. A major point in that previous post.

Second, safety ground and earth ground are electrically different. Technical reasons are numerous. Too complex for a discussion attempting to remain at a layman's level. But an important number was provided with the relevant concept: low impedance (ie "less than 10 feet'). Distance to the earthing electrode is critical.

Third, concepts unknown to laymen are even demonstrated by a long wire transmitter antenna. A 200 watt transmitter transmits. Touch one part of that antenna to feel no voltage. Touch another part to be shocked by over 100 volts. Why two completely different voltages on the same wire? Numerous technicals apply. Even the dead cow summarizes a relevant and significant concept.

Other electrical concepts also explain why a third prong on a wall plug is not earth ground. We need not discuss why in a layman discussion. But the technical reasons say why a protector must connect so short to earth ground; not to safety ground.

How good is your 'whole house' protector? No protector does protection. Protection is defined by that protector's earth ground - the 'art' of protection. How good is your earth ground? Even sharp wire bends or splices can compromise a 'whole house' protector. Electrical concepts even explain why two completely different voltages exist on the same antenna wire.

OP's Tivo may have one defective part because it was an incoming path from the cloud. And it provided another outgoing path to earth. Damage because an incoming path did not first connect low impedance (ie 'less than 10 foot') to earth where it entered the building. Not grounded to a wall receptacle safety ground. A low impedance connection to earth ground.

OP's damage would be traceable to an incoming wire that violated the concept.
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Old 06-23-2013, 09:38 PM   #9
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Exclamation WARNING - DANGER - Personal safety issue!

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First, do not earth the Tivo. <snip>
I'm no layman. That's the opposite of what I am.

In order to not earth/ground a TiVo, you'd either have to NOT connect it to a signal input, or you'd HAVE TO violate the electrical codes that apply to the grounding of cable systems, as well as antennas.

There's even many warnings and diagrams dedicated to this included with every TiVo.

Now that I know you don't know what you are talking about (when it comes to SAFETY), which I wanted to be sure of, first:

FOR THE SAFETY OF ANYBODY READING THIS THREAD: I BEG OF YOU TO STICK TO THE ELECTRICAL CODES THAT APPLY TO CABLE SYSTEMS AND ANTENNAS. - DO NOT TAKE WHAT SELF-PROCLAIMED EXPERTS SAY AS GOSPEL. SAFETY FIRST! - READ THE MANUALS, STUDY THE DIAGRAMS, & CHECK YOUR APPLICABLE ELECTRICAL/BUILDING CODES.

Sometimes it is far better to have the safety of a grounded (or "earthed") chassis, than to not have that, merely to increase the EXTREMELY unlikely chance of the internals surviving a lightning strike.

I will now bow-out, as I will not be party to, or an accomplice in, confusing anybody as to what is safe. We each are entitled to our opinions, and how we chose to interpret what we feel are guidelines.
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Old 06-23-2013, 10:44 PM   #10
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In order to not earth/ground a TiVo, you'd either have to NOT connect it to a signal input, or you'd HAVE TO violate the electrical codes that apply to the grounding of cable systems, as well as antennas.
Grasping these well understood concepts explains why a Tivo must be safety grounded. An earthed Tivo is a safety code violation. And would make that Tivo a potentially destructive connection to earth. Safety ground (also called equipment ground) and earth ground are electrically different.

Some mistakenly assume a wall receptacle ground can connect directly to an earth ground electrode. Clearly a code violation. Because safety ground (described by code as equipment ground) is electrically different from earth ground. Wall receptacles must be safety grounded; not earth grounded.

Why was the OP's Tivo damaged? A surge could have one incoming wire (ie AC electric). And another outgoing connection to earth (ie antenna). Damage because that Tivo made a destructive connection to earth.

If a surge is earthed, instead, by a low impedance ('less than 10 foot') connection, then no Tivo damage. All incoming wires to a Tivo (ie antenna, AC electric, network connection) must connect low impedance to the same 'single point earth ground' before entering the building.

Earth ground the surge. Safety ground a Tivo. Earthing a Tivo would also be a code (human safety) violation.
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Old 06-23-2013, 11:28 PM   #11
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<content intentionally removed>
You can keep it up until the cows come home, or don't, in the case of the one you killed for your story...

I'm not going to argue any further. The literature provided with TiVos disagrees with you (I double-checked). The cable company DEFINITELY disagrees with you (I asked them). The electrical codes disagree with you (I re-read them).

My point is, while some of what you say is true, you are putting things out there that could injure and/or kill people, if they take you seriously. Period. End of THAT discussion.

If you'd like to continue, how about getting back on hard-topic, which would be helping the original poster try to repair his TiVo? I think they should just take up TiVo on their offer, and get it replaced (if it has lifetime service).

That's what the thread was started for, by the original poster. I can't help without inspecting the unit, and testing components. Well, I could try, but it would be a lot of guess-work and relying on the OP to provide accurate information.

It should also be noted that the original poster only SPECULATED on what MAY HAVE happened to his TiVo, and why it didn't work after attempted repairs. Since they don't even know what truly caused the failure, I fail to see how anybody can really take this any further, except to try and address what the OP has asked, may ask, etc. This thread is pretty much dead, unless the OP speaks up on what THEY WANT at this point.

There are countless OTHER threads about the topics that we have overrun the OP's thread with. Why make another out of this one? Maybe I started the drift off-topic, but I'm trying to correct that now.
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Old 06-24-2013, 07:29 AM   #12
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If you'd like to continue, how about getting back on hard-topic, which would be helping the original poster try to repair his TiVo?
OP has two problems. First, fixing the Tivo.
Quote:
Damage occurs when a surge enters on one wire. And leaves on another. So what would be a path destructively through a Tivo? Generally, only one part in that path fails. Replace that one part and the Tivo would probably work. Problem is that most have no idea how to identify that part. Since most surge damage leaves no visual indication. So many assume all motherboard parts are destroyed.
It could have failed due to a manufacturing defect or a surge. Either way, most cannot identify or replace that one probably defective part. However, identifying that part would help solve the second problem.

Second is averting future damage. A Tivo may be the 'canary in a coalmine'. An inexpensive warning about future damage to all other appliances. And how to avert that damage.
Quote:
If a surge is earthed, instead, by a low impedance ('less than 10 foot') connection, then no Tivo damage. All incoming wires to a Tivo (ie antenna, AC electric, network connection) must connect low impedance to the same 'single point earth ground' before entering the building.
The cable company should have already implemented their part of this solution (that is even required by code). Details provided if a solution is desired.

Instead, numerous urban myths were exposed and dispelled. And some relevant concepts, often completely unknown to linemen and electricians, were defined.

The OP can learn from his 'dead canary' (a Tivo) by providing further details and asking relevant questions. Since even the electrical code requires some of what may be missing or compromised.
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Old 06-24-2013, 11:58 PM   #13
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Even if only one part failed in the TiVo, the other parts have been stressed. It's only a matter of time before they may go as well. Even if one part goes, a lightning surge is powerful enough to jump the gap (it jumped the thousands of feet from the sky, what's a few extra tenths of an inch?).

Plus, induced currents are a huge problem so it can damage components whose only relation was that they had two lines run beside each other.

And nothing protects against a lightning strike. Surge arrestors and other stuff protect against induced currents (which are lower than the main strike). Even the lightning rod on your house can't withstand the strike (it'll vaporize). (Trivia: lightning rods actually attract lightning. However, the goal is to discharge the potential difference so strikes don't happen, and the sharp pointy tips on the lightning rod help do that).
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Old 06-25-2013, 05:55 AM   #14
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Even if only one part failed in the TiVo, the other parts have been stressed. It's only a matter of time before they may go as well. .
First appreciate I was doing this stuff even long ago. We would learn / confirm how damage happens by literally replacing every damaged part. The repaired equipment would then run for years without failure.

Take the example of a 56K modem. In almost every case, the failed part was only a transistor that drove the line relay. Incoming path was usually AC mains. The current path was usually incoming into a computer motherboard via the AC safety ground wire. Across a motherboard into that modem. Through the damaged transistor. Into a relay coil. Out via the relay wipers (contacts) that make or break the telephone connection. The outgoing to earth via the phone line.

Only damaged part was that one transistor. No motherboard damage. No other modem part failed for years.

Second, appreciate the so many who 'assumed' damage was incoming on the phone line. Who knew only from observation combined with speculation. The typical message was "No Dial tone Detected". So many knew lightning was incoming on a phone line.

Most do not know that all phone lines already have a superior 'whole house' protector installed for free at every subecriber. And that damage is more often on the outgoing side; not the incoming side.

Again, unlike others, we literally learned this stuff by even replacing semiconductors. And by building protection systems that made direct lightning strikes irrelevant. Most failures are only one part. Overstress (another speculation) is rare.

Third, as for the induced surge, well, that is mostly myth. In every case, we would discover the so called induced surge was actually a direct strike. In one case, lightning struck a lightning rod. Only four feet from a wire that connected the entire lightning strike to earth was a PC. A complete lightning strike (maybe 20,000 amps) was only four feet from a PC. That would be a massive 'induced' surge. The PC did not even blink. But then do E-M field equations for an 'induced' surge. Due to what is already inside all electronics, an induced surge is somewhere between trivial and irrelevant.

Four, damage is about a current path maybe three miles down from the cloud and maybe four miles through earth to some earthborne charges. Even a strike to AC wires far down the street is a direct strike incoming to all household appliances; is not an induced surge.

We did this stuff as engineers. Wild speculation only from observation (what so many do to 'know' how damage happened) was never an acceptable analysis. We even broke open ICs to view under a microscope - to learn where currents traveled. To learn how and why damage occurs.

How would a Tivo be damaged? Well, it has numerous potential incoming and outgoing paths including antenna or cable, AC electric, a network or telephone line, and even furniture or floor it sits upon. Even wood can be an electrical conductor. Damage is usually found only on one part somewhere between the incoming and outgoing path. More often on the outgoing path to earth. Most who 'know' why damage happens cannot even identify each semiconductor let alone know why damage happens. We did. Therefore my posts will often disagree with others who only ‘know’ using observation combined with speculation.

If due to surge damage or due to a manufacturing defect (the latter is more common), then failed is usually only one part. Yes, exceptions exist. But protection from direct lightning strikes is so routine that damage is often considered a human mistake.

Last edited by westom : 06-25-2013 at 06:25 AM.
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Old 06-25-2013, 07:40 AM   #15
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We did this stuff as engineers. Wild speculation only from observation (what so many do to 'know' how damage happened) was never an acceptable analysis. We even broke open ICs to view under a microscope - to learn where currents traveled. To learn how and why damage occurs.
Funny, I did the whole "examine a split IC under a microscope" exercise, as well. I worked in both the medical engineering department, of what is now part of GE Medical, and a major gaming (gambling) engineering department (which I'm not allowed to name).

The medical exercise was to demonstrate just how damaging STATIC discharge (from not using proper ESD countermeasures when handling components) was to sensitive ICs. They'd still work, but would look like they'd been hit by a lightning bolt, under the microscope. You can surely imagine just how important it was, to keep ANY such damage from happening, being medical systems.

The gaming (gambling) exercise was part of the rigid testing to keep people from using stun guns to make machines pay-out. It was quite fun using the testing equipment, which created a bolt so intense, it would pit powder coating off the chassis, melt chrome, pit the base metal, destroy the CRT/LCD, and so on. But, all that was required was that the machine either keep working, or go into lockdown. Any malfunction meant back to work, and repeat testing, until those conditions were met.

All this experience we share, yet I still disagree with your statement that a TiVo chassis should NOT be "earthed" as you say, or "grounded" as I say (which some argue are two different things, while most have accepted they are the same thing).

In order for a TiVo to NOT have a grounded/earthed connection, you'd have to cut the shielding away from the outside of the coax of the antenna, or cable source, that you have to connect, in order to use the DVR/TV functions of the TiVo. THAT WOULD BE CIRCUMVENTING THE ELECTRICAL CODES!

So, unless you've been repeating the same misinformation, unintentionally, (or not realizing how MOST people would interpret it) everybody who has a proper coax ground, which electrical code REQUIRES, has an improperly connected TiVo. So, that would be ~95% of people, that you are saying their TiVos are not connected correctly? In what universe does that make any sense? The ~5% that don't have a proper coax shield-to-ground/earth connection are the right ones? ARE YOU KIDDING ME?

When it comes to consumer electronic devices, SAFETY and COMPLAINCE WITH CODES, ***ALWAYS*** trumps any deviation, solely for the purpose of such equipment POSSIBLY surviving a lightning strike.

I've also repaired damaged modems, and found the same as you found, regarding there USUALLY only being one component destroyed (whether or not you see any visual indications of damage to that component, with the naked eye alone).

So, I don't understand, how somebody who knows so much, can be so blind to the obvious fact that anything connected via coax, will have a grounded chassis. The only exception to that would be if the equipment had the coaxial input's outer connection isolated from the chassis. I can assure you, that every TiVo and cable STB/DVR I've ever laid eyes on, did not isolate the coax ground.

I've seen ONE item that did isolate it - a PCI TV tuner card. If you let the coaxial shell touch the chassis of the computer, then you created a ground-loop scenario, which that card addressed by isolation. Note that computer tower cases have a three-prong power source, so it's no mystery why isolation would be necessary.

I'm just trying to get you to stop saying, implying, (or stating in a way that would read to most people as) : "A TiVo should not be grounded/earthed". The only way that would be true, would be if they've been making them wrong, all these YEARS. What are the odds that the cableco STB/DVR units are all made wrong too??

If the coax shield isn't supposed to be grounded/earthed (which is not the case), then why does EVERY splitter rated for outdoor use have a grounding screw? Why does the CableCo have a grounding rod at every drop, with a thick, bare, copper wire between a ground and the drop tap? Should I go start tearing them all out? That'll certainly keep me busy (and get me arrested for tampering)!

Last edited by nooneuknow : 06-25-2013 at 07:53 AM.
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Old 06-25-2013, 07:56 AM   #16
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Funny, I did the whole "examine a split IC under a microscope" exercise, as well. I worked in both the medical engineering department, of what is now part of GE Medical, and a major gaming (gambling) engineering department (which I'm not allowed to name).

The medical exercise was to demonstrate just how damaging STATIC discharge (from not using proper ESD countermeasures when handling components) was to sensitive ICs. They'd still work, but would look like they'd been hit by a lightning bolt, under the microscope. You can surely imagine just how important it was, to keep ANY such damage from happening, being medical systems.

The gaming (gambling) exercise was part of the rigid testing to keep people from using stun guns to make machines pay-out. It was quite fun using the testing equipment, which created a bolt so intense, it would pit powder coating off the chassis, melt chrome, pit the base metal, destroy the CRT/LCD, and so on. But, all that was required was that the machine either keep working, or go into lockdown. Any malfunction meant back to work, and repeat testing, until those conditions were met.

All this experience we share, yet I still disagree with your statement that a TiVo chassis should NOT be "earthed" as you say, or "grounded" as I say (which some argue are two different things, while most have accepted they are the same thing).

In order for a TiVo to NOT have a grounded/earthed connection, you'd have to cut the shielding away from the outside of the coax of the antenna, or cable source, that you have to connect, in order to use the DVR/TV functions of the TiVo. THAT WOULD BE CIRCUMVENTING THE ELECTRICAL CODES!

So, unless you've been repeating the same misinformation, unintentionally, (or not realizing how MOST people would interpret it) everybody who has a proper coax ground, which electrical code REQUIRES, has an improperly connected TiVo. So, that would be ~95% of people, that you are saying their TiVos are not connected correctly? In what universe does that make any sense? The ~5% that don't have a proper coax shield-to-ground/earth connection are the right ones? ARE YOU KIDDING ME?

When it comes to consumer electronic devices, SAFETY and COMPLAINCE WITH CODES, ***ALWAYS*** trumps any deviation, solely for the purpose of such equipment POSSIBLY surviving a lightning strike.

I've also repaired damaged modems, and found the same as you found, regarding there USUALLY only being one component destroyed (whether or not you see any visual indications of damage to that component, with the naked eye alone).

So, I don't understand, how somebody who knows so much, can be so blind to the obvious fact that anything connected via coax, will have a grounded chassis. The only exception to that would be if the equipment had the coaxial input's outer connection isolated from the chassis. I can assure you, that every TiVo and cable STB/DVR I've ever laid eyes on, did not isolate the coax ground.

I've seen ONE item that did isolate it - a PCI TV tuner card. If you let the coaxial shell touch the chassis of the computer, then you created a ground-loop scenario, which that card addressed by isolation. Note that computer tower cases have a three-prong power source, so it's no mystery why isolation would be necessary.

I'm just trying to get you to stop saying, implying, (or stating in a way that would read to most people as) : "A TiVo should not be grounded/earthed". The only way that would be true, would be if they've been making them wrong, all these YEARS. What are the odds that the cableco STB/DVR units are all made wrong too??
There are ground isolators cable connecters, I have one given to me years ago when I had a big ground loop coming from the outside cable, I had almost 30vac from the outside cable to my house water pipe, so the cable co gave my this special ground cable isolators that solved my problem, when I connected up my Moca I re-checked the outside cable and the cable co had fixed the problem so I removed the isolator. My inside cable is connected to my water pipe for the ground.
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Old 06-25-2013, 08:13 AM   #17
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My inside cable is connected to my water pipe for the ground.
That cable to a water pipe is even a code violation. And can create other problems. It must connect short to the same earthing electrode used by all other incoming utility wires.

That isolator might be a classic example of curing symptoms. Many linemen will cure a symptom rather than address problems they do not understand. 30 volts on a ground implies a serious and ignored problem elsewhere. It may even indicate a risk to human life exists.

Well, sometimes a cable amp is defective. Rather than fix the amp, did they cure a symptom?

Cable must connect to the building's single point earth ground where it enters the building. As required by code for human safety. And also necessary to avert what may have caused the OP's damaged Tivo.
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Old 06-25-2013, 08:20 AM   #18
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All this experience we share, yet I still disagree with your statement that a TiVo chassis should NOT be "earthed" as you say, or "grounded" as I say (which some argue are two different things, while most have accepted they are the same thing).
Please stop putting words in my mouth. I never said that. You are misreading what was posted because you do not understand some basic concepts. Techs often do not understand how many different grounds are electrically different even when interconnected.

Do not "earth" the appliance. Earth the surge.

Earth is completely different from a safety / equipment / protective ground that the Tivo must be connected to. Earthng a Tivo can be a safety code violation. But that means learning of various and electrically different grounds.

Same electrical concepts (and electrical code) also say why a cable must not be 'earthed' to a water pipe.
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Old 06-25-2013, 08:32 AM   #19
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Please stop putting words in my mouth. I never said that. You are misreading what was posted because you do not understand some basic concepts. Techs often do not understand how many different grounds are electrically different even when interconnected.

Do not "earth" the appliance. Earth the surge.

Earth is completely different from a safety / equipment / protective ground that the Tivo must be connected to. Earthng a Tivo can be a safety code violation. But that means learning of various and electrically different grounds.

Same electrical concepts (and electrical code) also say why a cable must not be 'earthed' to a water pipe.
Yes, I do understand the damn concepts you won't stop going on about.

Your EXACT words a few posts back:

Quote:
First, do not earth the Tivo. That only makes a Tivo the better and destructive path to earth. Earth a surge. A major point in that previous post.
What on earth do you expect MOST PEOPLE to get from that?!?! Technically, and at the same time BASICALLY, as soon as you connect the (properly grounded/earthed) coaxial cable to the TiVo, the TiVo is now grounded/earthed, PERIOD.

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First, do not earth the Tivo.
Dangerous thing to say, considering most people here have no electrical and/or engineering experience! If everybody here knew what each of us knows, it wouldn't be so dangerous to say such a thing, then try to support it by spewing out pages of technical speak, that ~95% of the people on here would not understand (without spending a lot of time educating themselves, first, just to understand what you are saying, as well as what I'm saying back). I'm not saying everybody else is dumb. I'm just saying you'll likely never get ~94% to understand how many variants of grounding/earthing there are, why they are needed, and what the differences mean, other than a cow between a lightning bolt and earth equals one dead cow....

I gather from your dialect, that you are not native to the USA. It's not an insult, but the dialect you use seems to be creating a barrier.... or something.... I worked with a British guy that was just as educated as I was, but I never could understand anything in his dialect. Maybe that's why this got out of hand....

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Old 06-25-2013, 08:43 AM   #20
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Your EXACT words a few posts back:
Those "exact words" do not say "disconnect a Tivo from the safety / protective / equipment ground". But you misread the quote to assume an erroneous interpretation.

That difference between earth ground and safety ground is significant to the OP IF his Tivo was damaged by a surge.

Among the OP's potential defects might be a cable or antenna not connected low impedance (ie 'less than 10 feet') to the "single point earth ground". Even that wire length number (not wire thickness) is critical. Even connecting to a water pipe can make damage easier. Significant are the electrical differences between a safety grounded Tivo and an "earthed" surge.

Tivo must not be "earthed'. A potentially destructive surge must be earthed.
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Old 06-25-2013, 08:59 AM   #21
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Those "exact words" do not say "disconnect a Tivo from the safety / protective / equipment ground". But you misread the quote to assume an erroneous interpretation.

That difference between earth ground and safety ground is significant to the OP IF his Tivo was damaged by a surge.

Among the OP's potential defects might be a cable or antenna not connected low impedance (ie 'less than 10 feet') to the "single point earth ground". Even that wire length number (not wire thickness) is critical. Even connecting to a water pipe can make damage easier. Significant are the electrical differences between a safety grounded Tivo and an "earthed" surge.

Tivo must not be "earthed'. A potentially destructive surge must be earthed.
Then go "earth" yourself. Your mishmash wording/dialect is a potentially destructive surge. So, now you know what you must do. Problem solved! Yay!

In retrospect, I should've just figured most people would be thinking "What the hell does he mean by earthing a TiVo?", and then unsubscribed from the thread, like I'm going to do as soon as I finish this.

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Old 06-25-2013, 03:26 PM   #22
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That cable to a water pipe is even a code violation. And can create other problems. It must connect short to the same earthing electrode used by all other incoming utility wires.

That isolator might be a classic example of curing symptoms. Many linemen will cure a symptom rather than address problems they do not understand. 30 volts on a ground implies a serious and ignored problem elsewhere. It may even indicate a risk to human life exists.

Well, sometimes a cable amp is defective. Rather than fix the amp, did they cure a symptom?

Cable must connect to the building's single point earth ground where it enters the building. As required by code for human safety. And also necessary to avert what may have caused the OP's damaged Tivo.
What code, my main ground is made about 35 feet from the inside breaker panel, the copper earth rod, meter, and master 200 amp breaker are outside on the side of my garage, about 35 feet from the panel, the neutral, copper ground wire, and inside water pipe clamp with another copper wire go out under the garage floor this 35 feet to the master ground that inside the meter box, the cable ground just goes to a nearby water pipe. This was a new home and the town inspected the total 220VAC wiring system, and ground, and said it passed, the system was all laid out by a licensed electrician and passed on by the town before I started. It is hard to believe that Comcast breaks code by grounding the cable on the inside water pipe as they do on all instillations in my area.
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Old 06-25-2013, 05:24 PM   #23
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It is hard to believe that Comcast breaks code by grounding the cable on the inside water pipe as they do on all instillations in my area.
Really? Comcast techs aren't electricians and I'm pretty sure they get no electrical code training whatsoever.
Just because your house passed inspection doesn't mean anything. Either your cable installation was made after the final inspection of your house, or the inspector is not following the latest code (yet).
In the latest electrical code (2011), all systems that require a ground must all connect to the same point at the electrical service.


Edit: Just found this ... relevant to the discussion at hand (I think).

http://www.mikeholt.com/mojonewsarch...d~20040427.php

Quote:
By having all equipment, including antenna transmission lines, power, telephone, cable TV, etc, all entering the facility at nearly the same point and all being bonded to a single common ground point, little current will flow between these systems and therefore there will be essentially no difference of potential between the components of the system (everything within the shelter) during lightning activity. The environment is safer for personnel and the equipment has a much higher probability of surviving significant lightning activity. We must also consider that there may be inductively coupled energy from a nearby lightning strike that would be coupled into the facility structure or circuit conductors within the facility. This however is not part of and is not directly related to the single point ground. You must also consider suitable surge suppressors for ungrounded circuit conductors entering/exiting the facility.

On the other hand if you have antenna transmission lines entering the facility at one point and power, telephone, cable TV, etc circuit conductors entering the facility at different points you will have current flowing through the connected equipment as energy attempts to equalize during lightning activity. This is true even if all of these systems and the equipment are connected to the site ground system you describe. The problem is they would be connected to the system at different points and as the example below points out the voltage between these different points may be many kV during lightning activity. Consider that your internal equipment is also a part of the circuit path. The transmission line from one direction and the power etc. circuits from another direction. This constitutes a series-parallel circuit between opposite ends of the shelter or different parts of the system. You have the interior ground conductors, exterior ground conductors in addition to the conductors interconnecting the equipment making up the series-parallel circuit. This could result in personal injury, equipment damage and system failure.

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Old 06-25-2013, 11:36 PM   #24
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What code, my main ground is made about 35 feet from the inside breaker panel, the copper earth rod, meter, and master 200 amp breaker are outside on the side of my garage, about 35 feet from the panel,...
You are confusing minimal requirement for 'human safety' with something completely different and not defined by code - 'transistor safety'.

I once discussed this with two Comcast techs who had just taken Comcast's training for earthing. They (like techs and electricians) were told rules. But had no idea why those rules existed. Did not even understand the difference between earth and safety grounds. As I explained relevant concepts (ie low impedance), one tech repeatedly discovered, "That's what they were talking about." They were told what to do. But were never told why.

In one installation, they had routed a cable directly to a TV on the second floor. They did not understand why TV cable must first drop down to an earth ground electrode. And then rise back up to the second floor. They thought a long 10 AWG wire to the earth ground from the second floor was sufficient. By combining what they had been taught in class with addition facts, they realized they had improperly earthed that installation.

Worse are satellite dish installers who receive no such training. Their installations are often so poor as to offer no 'transistor safety' as well as violate basic code requirements for 'human safety'.

A citation from steve614 is also demonstrated by an application note from a utility - the good, bad, and ugly (preferred, wrong, and right) solutions:
http://www.duke-energy.com/indiana-b...ech-tip-08.asp
This app note demonstrates what is necessary for "single ooint earth ground" to protect a Tivo and all other household appliances.

To protect a Tivo, every incoming wire (telephone, AC, cable, antenna, dish, etc) must make a low impedance (ie 'less than 10 foot') connection to earth. A 'whole house' protector (installed for free by every telco) must connect that short. Cable must have a hardwired connection that is just as short or shorter. Each incoming AC wire (earthed via a 'whole house' protector) may require a 'whole house' protector in the meter panel or behind the meter. Or elsewhere so make that always required short (ie 'less than 10 foot') connection to the earthing electrode.

Just because an installation meets 'human safety' requirements does not say it meets 'low impedance' transistor (Tivo) safety requirements. Many want to play games with the rules using lawyer logic rather than address fundamental electrical concepts as an engineer (a realist). That connection to single point earth ground must be that short or shorter. Not required for human safety. Absolutely required for transistor (and Tivo) safety.
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Old 06-26-2013, 12:39 AM   #25
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Really? Comcast techs aren't electricians and I'm pretty sure they get no electrical code training whatsoever.
Just because your house passed inspection doesn't mean anything. Either your cable installation was made after the final inspection of your house, or the inspector is not following the latest code (yet).
In the latest electrical code (2011), all systems that require a ground must all connect to the same point at the electrical service.


Edit: Just found this ... relevant to the discussion at hand (I think).

http://www.mikeholt.com/mojonewsarch...d~20040427.php
I guess my home could not be built with a correct ground point as you say as my ground point is 35 feet from the panel, and there is no way I could change that as the power comes into the home from under the garage floor, to meet code for my town I had to put the main breaker/meter box and ground bar on the outside of my home, the neutral/ground/water pipe all connect to this ground by separate wires that all have to be over 35 feet long, the water pipe comes into my home another 60 feet from the panel so that ground wire is almost 100 feet. Don't know what I could do about this.
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Old 06-26-2013, 08:34 AM   #26
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I guess my home could not be built with a correct ground point as you say as my ground point is 35 feet from the panel, and there is no way I could change that as the power comes into the home from under the garage floor, to meet code for my town I had to put the main breaker/meter box and ground bar on the outside of my home, the neutral/ground/water pipe all connect to this ground by separate wires that all have to be over 35 feet long, the water pipe comes into my home another 60 feet from the panel so that ground wire is almost 100 feet. Don't know what I could do about this.
No, sounds like your house has the correct ground point. The ground point is to be made at the service entrance which would be at the meter/main breaker box outside.
Only thing that may be in question is the neutral, as that should be bonded to ground inside the main breaker box outside, and not at the panel.

The thing for sure, is that the ground for your cable TV is not correct. At the very least, they should have used the same copper pipe that the electrical service uses.
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Old 06-26-2013, 10:42 AM   #27
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No, sounds like your house has the correct ground point. The ground point is to be made at the service entrance which would be at the meter/main breaker box outside.
Only thing that may be in question is the neutral, as that should be bonded to ground inside the main breaker box outside, and not at the panel.

The thing for sure, is that the ground for your cable TV is not correct. At the very least, they should have used the same copper pipe that the electrical service uses.
The cable service does use the same copper pipe that the electrical service uses except that the electrical service uses a connection that is before the water meter, the cable is way after the water meter so there are many solder points between the two, but there is a ground strap around the water meter.

The neutral is bonded outside at the main breaker not at the panel, the panel neutral bar is not connected to the panel box as the ground bar is, there is a screw that would let the neutral bar connect to the panel box, but it is not being used.
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Old 06-26-2013, 01:33 PM   #28
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The neutral is bonded outside at the main breaker not at the panel, the panel neutral bar is not connected to the panel box as the ground bar is, there is a screw that would let the neutral bar connect to the panel box, but it is not being used.
If the neutral, safety grounds, and earth ground do not meet in the main breaker box, then that screw must be removed (as an electrician has properly done).

A 'whole house' protector would work only if in the other box or behind the meter - where the connection to earth is low impedance (ie 'less than 10 feet'). Cable, telephone, satellite dish, etc wires must also enter at that point (the service entrance) to also make a low impedance earthing connection.

Relevant earthing concepts are demonstrated by a tech-tip at:
http://www.duke-energy.com/indiana-b...ech-tip-08.asp

That mikeholt.com citation also demonstrates what was prviously discussed - the dead cow example. Says why the dead cow example explains Tivo damage. The term single point earth ground is critically important.

Cable, as installed, has an inferior earth ground. Each solder joint, sharp pipe bend, and an excessive distance to a service entrance ground all put cable appliances at greater risk.

Code only addresses human safety. So some of that installation meets code. Code says nothing about transistor safety. The 'not low impedance' cable ground means cable appliances (ie Tivo) are at risk for the same reason that cow was killed.

The installation, as described, violates concepts even demonstrated in that tech-tip. A common problem because so many electricians and linemen are never taught this stuff.

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Old 06-26-2013, 04:48 PM   #29
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If the neutral, safety grounds, and earth ground do not meet in the main breaker box, then that screw must be removed (as an electrician has properly done).

A 'whole house' protector would work only if in the other box or behind the meter - where the connection to earth is low impedance (ie 'less than 10 feet'). Cable, telephone, satellite dish, etc wires must also enter at that point (the service entrance) to also make a low impedance earthing connection.

Relevant earthing concepts are demonstrated by a tech-tip at:
http://www.duke-energy.com/indiana-b...ech-tip-08.asp

That mikeholt.com citation also demonstrates what was prviously discussed - the dead cow example. Says why the dead cow example explains Tivo damage. The term single point earth ground is critically important.

Cable, as installed, has an inferior earth ground. Each solder joint, sharp pipe bend, and an excessive distance to a service entrance ground all put cable appliances at greater risk.

Code only addresses human safety. So some of that installation meets code. Code says nothing about transistor safety. The 'not low impedance' cable ground means cable appliances (ie Tivo) are at risk for the same reason that cow was killed.

The installation, as described, violates concepts even demonstrated in that tech-tip. A common problem because so many electricians and linemen are never taught this stuff.
I see no practical way to meet the ground requirements you set out as my main water pipe comes into my home far from the main earth ground and the cable is all underground until it get to my cellar, I guess I will have to take the risk.
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Old 06-26-2013, 06:08 PM   #30
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I see no practical way to meet the ground requirements you set out as my main water pipe comes into my home far from the main earth ground and the cable is all underground until it get to my cellar, I guess I will have to take the risk.
Of all earth grounds defined by code, only a water pipe earth ground is insufficient. A buklding can have only one earth ground of any other type. But the building must always have some other type earth ground even if a water pipe ground exists. A water pipe earth ground is the least acceptable earthing electrode. Made even worse in your case because it is so far away.

Your single point earth ground must not be a water pipe for a long list of reasons (some listed previously). Proper protection of a Tivo means earthing that both meets and exceeds code. If your earth ground is only that water pipe, then you do not even meet code.

For most, a best earth ground is one or a few 10 foot copper clad ground rods. Sledge hammered into earth at the service entrance. To meet code. And to also make a 'whole house' protector effective. Details apply to this 'art' called earthing.

A primary reason for that 6 AWG wire to a water pipe is human safety. To remove stray currents that would (for example) harm someone in the shower. Many reasons for it are beyond the scope of this discussion. But to protect a Tivo, you muist have a service entrance earth ground that both meets and exceeds code requirements.

Cable should have an interface box where their cable meets yours. As even required by code to make the earth ground connection. It is required by code for 'human safety'. And is properly installed for also for 'transistor safety'.

Numerous solutions probably exist for your cable problem. Likely solved by rerouting. A fundamental rule is simple. A first thing that cable must connect to is single point earth ground. Otherwise the entire household protection system is compromised - for reasons similar to lighting striking a nearby tree kills a nearby cow.
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