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Tivo HD - no sound until reboot

5K views 12 replies 5 participants last post by  dlfl 
#1 ·
I am having an issue with my Tivo HD, which has not been modified in any way. The problem is that on three occasions in the past two months I have had to reset the box to fix a no audio problem. I do hear the Tivo beeps but there is no audio on live or recorded shows. The Tivo is connected to the TV via an HDMI cable, and there is also a digital audio connection to the AVR and the sound is affected through both of these connections. I have it connected this way so that I can either just listen though the TV via the HDMI, or use the surround sound system. The last couple of times this happened I switched between the two to make sure the audio was affected through both connections. I have the issue right now but am not rebooting in case there is something else I can do. Is this an issue others have seen or perhaps the Tivo is failing? I have lifetime service on this Tivo, but I believe that only applies to the Tivo service and not the hardware. Thanks!
 
#2 ·
If you have a Series 3 platform unit (TCD648250, TCD652160, TCD658000) there's an excellent chance that your power supply is suffering from "capacitor plague".

However, having HDMI involved introduces that as a point of failure/problems/gremlins as well, so disconnect it and use the component or composite or S-Video out and see if you still have the problem.
 
#3 ·
Thanks for the response! If I am following you correctly, you are saying that the HDMI connection might be causing the sound problem out of the digital audio and HDMI audio connections, and if I eliminate the HDMI that this might fix the problem. If it does, is this an indication that some other components are bad, or the power supply? If this does not fix it then I may want to look into the power supply as being the cause. Are there cap replacement kits, or power supply replacements?
 
#4 ·
HDMI itself, as implemented in the TiVo and the device at the other end, can exhibit such quirks. HDMI is a solution that's worse than the problem. Try power-cycling your TV the next time this happens. That might kick the HDMI out of whatever lock condition it's in without having to wait for your TiVo to reboot. First try just disconnecting and reconnecting the HDMI cable.

Checking for bulging capacitors and, even better, checking the voltage levels from your power supply is a good thing to do -- PS failures are not unusual.
 
#5 ·
Thanks for the response! If I am following you correctly, you are saying that the HDMI connection might be causing the sound problem out of the digital audio and HDMI audio connections, and if I eliminate the HDMI that this might fix the problem. If it does, is this an indication that some other components are bad, or the power supply? If this does not fix it then I may want to look into the power supply as being the cause. Are there cap replacement kits, or power supply replacements?
You can unsolder the bad capacitors yourself and replace them for about $10 or you can pay $100 or more for a replacement power supply.
 
#6 ·
You can unsolder the bad capacitors yourself and replace them for about $10 or you can pay $100 or more for a replacement power supply.
I am so glad I found this thread. Thanks for the information. One last question though, what capacitors are the right ones to get? I only know how to solder but know nothing about capacitors :confused: ... please advise...:)
 
#7 ·
I am so glad I found this thread. Thanks for the information. One last question though, what capacitors are the right ones to get? I only know how to solder but know nothing about capacitors :confused: ... please advise...:)
Which model TiVo do you have?

On the sticker on the back where the power cord plugs in there is a model number that starts with TCD (unless you have a Series 1, a Direct TV TiVo, or one of the Series 2 models made by Sony, Humax, Pioneer, or Toshiba).

What is that number?

It wouldn't hurt for you to read Wikipedia's page on "capacitor plague".

The power supply will have one capacitor that's physically larger than the rest by a good margin and is rated for 200 Volts or more.

I've never heard of one of those going bad, and unless the top is bulged you should be able to ignore it.

It only deals with the 120 V AC from the wall socket after it's turned into DC, at which point it has some 60 cycle per second, or 120 cycle per second, "ripple" which the big cap filters. This is not especially taxing on that big cap.

It's when that filtered DC is turned on and off (chopped) thousands of times per second to turn it back into lower voltage AC which is turned into lower voltage DC that the capacitors doing the filtering have to deal with that much higher frequency "ripple", which works them a lot harder.

Because of that they have to be "premium grade", so to speak, and because capacitor plague (in the type of capacitor known as an electrolytic capacitor) is caused by a bad electrolytic formula that resulted in caps that weren't up to snuff to begin with, the harder work revealed the flaws much, much sooner than "good" caps would have slowly gone bad from old age.

Those will be the caps that are smaller than the big one and bigger than the few really little ones on the power supply board.

They'll tend to be near the heat sink(s).

The really little ones shouldn't need to be worried about, either.

What you will need are capacitors that are specifically stated to be Low ESR.

(stands for Equivalent Series Resisitance, and basically the lower it is, the better it works in high frequency switching circuits where there's a lot of current moving in and out of them all the time, because the lower resistance means less heat)

But there's still potential for heat, so you also need capacitors rated for 105 degrees Centigrade/Celsius (which is hotter than the boiling point of water).

The kind of general purpose electrolytic caps you find at Radio Shack tend to only be rated for 85 degrees C.

They will need to be the same rating in microFarads (the Farad is the unit in which capacitance is measured) as the ones they are replacing, so if the old one says 2200uF, so should the new one.

The other thing is the voltage rating. It needs to be at least as high as the voltage rating on the one you're replacing, but you can get away with going to the next step up if necessary.

For example, if the original is rated at 10 Volts, but there aren't any 10V units at the same uF in stock, you could go with 16 V units, 25V if you absolutely have to. But you can't drop below 10V if that's what the original one is.

There's another thread around here with some cap lists for different Series 3 models, and I'm going to be adding some info to it soon.

But lets start with which model number your Tivo is, what its symptoms are, and whether you've had the lid off and eyeballed things yet.
 
#8 ·
Which model TiVo do you have?

But lets start with which model number your TiVo is, what its symptoms are, and whether you've had the lid off and eyeballed things yet.
Thanks for the quick response.
model number is TDC652160. Symptoms are that sound on my TV just stop. I unplug and replug in the TiVo until sounds comes back. Sometimes it happens after one try.. most of the time it doesn't.

I haven't taken the lid off as of yet. Wanted to know which capacitors to get before even starting that process. Looking up Capacitor plague now...
 
#9 ·
Thanks for the quick response.
model number is TDC652160. Symptoms are that sound on my TV just stop. I unplug and replug in the TiVo until sounds comes back. Sometimes it happens after one try.. most of the time it doesn't.

I haven't taken the lid off as of yet. Wanted to know which capacitors to get before even starting that process. Looking up Capacitor plague now...
The 652 used two different models of power supply by two different manufacturers, so we need to know which one you've got before suggesting a list, but I'll get you started.

There will be a big cap, rated at 200 Volts or better.

It's almost sure NOT to be the problem or need replacing.

There will be some little ones. Again, almost certainly not the problem and can safely be ignored.

Threre will be several whose sizes are in between those two extremes and they'll be clustered near the heat sink(s).

If you have one or more bad caps, they're almost certain to be in that group.

If there's a Harbor Freight Tools store in your area, see my post about free voltmeters in the

TiVo Coffee House - TiVo Discussion

forum

http://www.tivocommunity.com/tivo-vb/showthread.php?t=510320

In case none of your caps show any visible signs of problems, you can check the DC outputs of the supply to see if any of them are lower (or perhaps higher, but most likely lower) than they're supposed to be.

You'll need a #10 Torx bit to remove the screws holding the top onto the case--although once you get them out you'll probably find that there's also a lot of friction holding it as well, and you may have to pry it straight back a hair before the front lip is clear and you can lift.

Of course you do this with it unplugged, which reminds me--the first rule of working on TiVos:

ALWAYS KNOW WHERE BOTH ENDS OF THE POWER CORD ARE AT ALL TIMES

That same #10 driver will also work to remove the hard drive bracket, and the drive from the bracket, if necessary, and to remove the screws that hold the power supply board down. Except for the dark screw that goes in from the outside just above the power supply's AC input jack. For that, you will need the slightly smaller #8 Torx bit.

You need to have the power supply plugged into the motherboard when it's energized--switch mode power supplies don't like working without a load connected.

You can jamb the meter's black (negative) lead into a hole in the metal chassis somewhere on the side away from the power supply for your ground connection, and use the red lead to back probe the motherboard socket plug.

The yellow wire is supposed to be +12 Volts, the red wire +5 V, and the orange wire +3.3 V.

The black wires coming from the supply are grounds.

Voltage readings shouldn't be more than around + or - a half a Volt of off nominal.

It's not the worst idea in the world to plug the power supply cord into one of those outlet strips that have a switch, so that you can connect or disconnect it from the wall socket electrically with something easily within reach instead of having to plug and unplug at the wall socket.

The power supply is not shielded like a PC power supply is, so there's 120 V AC with 15 Amps of current available before the breaker even thinks about tripping sitting there on some of the metal parts just waiting for another path to ground, like a dropped screwdriver or a careless hand.
 
#10 ·
The 652 used two different models of power supply by two different manufacturers, so we need to know which one you've got before suggesting a list, but I'll get you started.
I attached some of the pictures after opening up my TiVo. Doesn't look like it's one of the capacitors (bummer). I was hoping it would be as easy as unsoldering and soldering
 

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#11 ·
I attached some of the pictures after opening up my TiVo. Doesn't look like it's one of the capacitors (bummer). I was hoping it would be as easy as unsoldering and soldering
Any cap that shows any bulge at all is bad, but a bad cap may not show any bulge.

You should check the voltages to see if any of them are "off".

I can tell which of the 2 TCD652160 power supplies you have by your pictures, so in the next day or 3 when I make a list of the caps to replace if someone wants to just replace all the ones that might be problematic all at once, I'll do that model first.

If all 3 voltages on yours are more or less uniformly low, there's an adjustment potentiometer (kinda like a volume control, it's a variable resistance resistor) on your model that we can carefully play with.

But if you get like 3.3 and 5 more or less right on the nose but 12 is closer to 11, then it's almost certainly a bad cap or two.
 
#12 ·
Any cap that shows any bulge at all is bad, but a bad cap may not show any bulge.

You should check the voltages to see if any of them are "off".

I can tell which of the 2 TCD652160 power supplies you have by your pictures, so in the next day or 3 when I make a list of the caps to replace if someone wants to just replace all the ones that might be problematic all at once, I'll do that model first.

If all 3 voltages on yours are more or less uniformly low, there's an adjustment potentiometer (kinda like a volume control, it's a variable resistance resistor) on your model that we can carefully play with.

But if you get like 3.3 and 5 more or less right on the nose but 12 is closer to 11, then it's almost certainly a bad cap or two.
I would really appreciate your list unitron. I have a bad cap on this same board at the C503 location and I might as well replace the others while I'm at it. Thanks
 
#13 ·
.......
Voltage readings shouldn't be more than around + or - a half a Volt of off nominal.
........
Half a Volt is way too much for the 3.3V and 5V. They should be within +/-5%.
I believe +/-10% (1.2V) is OK for the 12V although it might also be +/-5% (0.6V).

Of course this assumes your meter is accurate, which means it's either spec'ed that way or has been calibrated against an accurate meter.
 
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