[hunts]

_____________________________________________________________

If so you have heat but yes check the tip to see if it's tight. If you can turn it with you fingers you need to use something to get it nice and tight. 40w should easily melt that junk solder I used a 28w pin once it took a long time but it worked. Are you using a solder sucker? If yes try to move the cap with heat on one leg it could be a clogged solder sucker.

I just bought this 40w soldering iron as I thought my 30w was broken (I did break it trying to mess with the head screw as it sheared off). This tip is secure and getting hot to melt the 2 types of solder that I have on hand, its just not melting what is on the board.

 

[Agent86]

I just bought this 40w soldering iron as I thought my 30w was broken (I did break it trying to mess with the head screw as it sheared off). This tip is secure and getting hot to melt the 2 types of solder that I have on hand, its just not melting what is on the board.

I fought with this when I did my S3 and my HD.

As others have mentioned, the trick is to get new solder introduced to the existing joint. Generally speaking simply tinning/coating the tip with solder seems to work for most people, but I didn't have any success with it.

What worked for me was to heat the joint and then add the smallest amount of new solder to it. Essentially working like I was creating a new joint. It did not look like the heat was doing anything to the joint at all, but as soon as I added the new solder the entire pad liquified and was easily removed.

 

[HerronScott]

What worked for me was to heat the joint and then add the smallest amount of new solder to it. Essentially working like I was creating a new joint. It did not look like the heat was doing anything to the joint at all, but as soon as I added the new solder the entire pad liquified and was easily removed.

This should definitely work. I believe Tim was alluding to it above and I should have mentioned it in addition to just tinning the tip.

Scott

 

[hunts]

I fought with this when I did my S3 and my HD.

As others have mentioned, the trick is to get new solder introduced to the existing joint. Generally speaking simply tinning/coating the tip with solder seems to work for most people, but I didn't have any success with it.

What worked for me was to heat the joint and then add the smallest amount of new solder to it. Essentially working like I was creating a new joint. It did not look like the heat was doing anything to the joint at all, but as soon as I added the new solder the entire pad liquified and was easily removed.

What a pain in the arse but this worked. The series 3 tivo is alive again and I think with no damage to my piss poor soldering skills.

 

[unitron]

What a pain in the arse but this worked. The series 3 tivo is alive again and I think with no damage to my piss poor soldering skills.

Congrats!

:up::up::up:

(it's the rosin flux in the new solder's rosin core that actually does the trick--flux means "flow", at least where soldering is concerned)

 

[shawn_t]

FYI: I have an HD XL with the 652 power supply.

Can someone sum up the steps involved in testing the various voltages safely under load? I've read through this thread and I'm still a little unclear. Should I remove the power supply board, flip is upside down to locate the rails for testing the different voltages and then make sure it is plugged into the motherboard and HD so it is under load?

...or should I just leave the HD plugged in and test using probes directly into the 14-pin molex connector?

I made the mistake of replacing only C501, C502, C504 and C701 yesterday, as they are the only ones that showed bulging, but still absolutely no sign of life so I am going to replace all the capacitors this time and see if I have better luck.

 

[timhbtr53]

FYI: I have an HD XL with the 652 power supply.

Can someone sum up the steps involved in testing the various voltages safely under load? I've read through this thread and I'm still a little unclear. Should I remove the power supply board, flip is upside down to locate the rails for testing the different voltages and then make sure it is plugged into the motherboard and HD so it is under load?

...or should I just leave the HD plugged in and test using probes directly into the 14-pin molex connector?

I made the mistake of replacing only C501, C502, C504 and C701 yesterday, as they are the only ones that showed bulging, but still absolutely no sign of life so I am going to replace all the capacitors this time and see if I have better luck.

_____________________________________________________________

Make sure the HDD and the system board is all plugged in to test. It not a good thing to run a switching supply without a load. Look at the pic I have attached and be extra safe. Hope this helps.
Tim FYI you might have to use the magnifier to see the lines

 

[timhbtr53]

It's still small type but it's the test points

 

[unitron]

FYI: I have an HD XL with the 652 power supply.

Can someone sum up the steps involved in testing the various voltages safely under load? I've read through this thread and I'm still a little unclear. Should I remove the power supply board, flip is upside down to locate the rails for testing the different voltages and then make sure it is plugged into the motherboard and HD so it is under load?

...or should I just leave the HD plugged in and test using probes directly into the 14-pin molex connector?

I made the mistake of replacing only C501, C502, C504 and C701 yesterday, as they are the only ones that showed bulging, but still absolutely no sign of life so I am going to replace all the capacitors this time and see if I have better luck.

The power supply needs to be fully, completely, and properly installed and it needs to be plugged into the motherboard.

Take the voltmeter negative lead and either clip it to the chassis on the side farthest (furthest?) away from the power supply if it has a 'gator clip on the end, or it it's a needle probe type, wedge it into one of those "cutouts" with the springy dimpled thing.

Just make sure you have good metal to metal contact.

Have a needle probe on the positive end, set the meter for 0-20 V DC or 0-25 or whatever the lowest setting is that's at least as high as 0-15.

"Backprobe" the plug plugged into the motherboard.

The way the plug segregates the wires (and the metal things on the end of them) from one another helps prevent accidentally shorting 2 of them together with the meter lead tip, and keeps you farther (further?) away from the unshielded power supply itself.

Yellow wire is the 12V line.

Gray wire (on 648 power supplies) is the 7.5V line which doesn't exist on either of the 652/658 power supply models

Red wire is the 5V line.

Orange wire is the 3.3V line.

The multiple red wires are tied together back at the power supply circuit board, so testing any of them is testing all of them.

Same deal with the orange ones.

Test with the hard drive plugged in and with it disconnected, but shut off power to the TiVo before plugging or unplugging the hard drive connector.

The reason to test it both ways is to look for very little difference in the readings, a sign that the power supply is performing its voltage regulation duties properly.

And remember the first rule:

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

The chances of getting readings of exactly 12V and exactly 7.5V and exactly 5V and exactly 3.3V on any one power supply are slim and none, and slim's just about over the horizon.

But they should all be fairly close to their nominal value.

 

[shawn_t]

It looks like my fuse is blown. Anyone know where I can get the correct fuse or equivalent replacement? It says T3AL / 250V on the circuit board. I think it is a 3.15 amp 250 VAC pigtail fuse. The size is 5mm x 20mm.

Thanks,

Shawn

 

[shawn_t]

The power supply needs to be fully, completely, and properly installed and it needs to be plugged into the motherboard.

Take the voltmeter negative lead and either clip it to the chassis on the side farthest (furthest?) away from the power supply if it has a 'gator clip on the end, or it it's a needle probe type, wedge it into one of those "cutouts" with the springy dimpled thing.

Just make sure you have good metal to metal contact.

Have a needle probe on the positive end, set the meter for 0-20 V DC or 0-25 or whatever the lowest setting is that's at least as high as 0-15.

"Backprobe" the plug plugged into the motherboard.

The way the plug segregates the wires (and the metal things on the end of them) from one another helps prevent accidentally shorting 2 of them together with the meter lead tip, and keeps you farther (further?) away from the unshielded power supply itself.

Yellow wire is the 12V line.

Gray wire (on 648 power supplies) is the 7.5V line which doesn't exist on either of the 652/658 power supply models

Red wire is the 5V line.

Orange wire is the 3.3V line.

The multiple red wires are tied together back at the power supply circuit board, so testing any of them is testing all of them.

Same deal with the orange ones.

Test with the hard drive plugged in and with it disconnected, but shut off power to the TiVo before plugging or unplugging the hard drive connector.

The reason to test it both ways is to look for very little difference in the readings, a sign that the power supply is performing its voltage regulation duties properly.

And remember the first rule:

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

The chances of getting readings of exactly 12V and exactly 7.5V and exactly 5V and exactly 3.3V on any one power supply are slim and none, and slim's just about over the horizon.

But they should all be fairly close to their nominal value.

Thanks Unitron,

I'll post my voltages once I get the fuse replaced and have the power supply up and running again!

 

[shawn_t]

Just for reference, here is a picture of the blown fuse

 

[timhbtr53]

Just for reference, here is a picture of the blown fuse

Mouser has them

http://www.mouser.com/ProductDetail...xU2g/1juGqdOFGo22Ydio1RGNkEquAXds1e3CJ2xuoA==

 

[timhbtr53]

Just for reference, here is a picture of the blown fuse

_____________________________________________________________

I think I would run the board for shorts first. Make sure there is no solder bridges anywhere. Check the Bridge Rectifier then all the caps.

 

[unitron]

Just for reference, here is a picture of the blown fuse

Pretty sure you've got a bad short somewhere.

Order several of those fuses, just in case you only think you've found and fixed the problem.

 

[shawn_t]

I have ordered 10 fuses

I have also visually inspected the board thoroughly and I don't see any evidence of a solder bridge with the capacitors I replaced. I also triple checked that the capacitors I replaced were installed with proper polarity. I will spend more time probing for shorts as well.

Any tips or suggestions on identifying shorts? There are some solder bridges on the board that seem to be there on purpose, but without a schematic I can't be positive. I'll post some pictures when I get home. This TiVo HD XL was in use for years before it went down so I'm assuming the power supply didn't have any bad shorts from the factory.

 

[timhbtr53]

There is a MOV across the input on the AC line make sure it good. There or some diodes on the bottom of the board "look like little zener diodes" check them first. I had one that shorted and it looked like the forth of July every time I put a new fuse in. I don't know if you have any resettable fuses laying around they or cheap but hard to find here lately. Are if you have a variable ac power supply to start up low and work it up to 120. It's only draws about 38w so you don't need much but for god sake make sure your EXTRA careful with live AC around you hands. No matter how much you like your TiVo it's not worth your life. Let me know if you find out if one of the diodes is bad.

 

[shawn_t]

As expected the fuse immediately blew when I replaced it. I removed the MOV and tested the resistance and it is open loop so does that mean it is bad or that the resistance is infinitely high because there is no AC current applied?

I also took a look at the zener diodes and they look ok visually but they are so tiny I can't really remove a lead to test nor do I think I could replace them.

I have always avoided the primary side of power supplies so perhaps it is time for me to get a new power supply. Any suggestions on how I can get one for a reasonable price? Weaknees seems a little too expensive for me because I live in Hawaii so shipping is going to add up. Perhaps eBay or do you guys sell refurbished power supplies?

Thanks

 

[timhbtr53]

As expected the fuse immediately blew when I replaced it. I removed the MOV and tested the resistance and it is open loop so does that mean it is bad or that the resistance is infinitely high because there is no AC current applied?

I also took a look at the zener diodes and they look ok visually but they are so tiny I can't really remove a lead to test nor do I think I could replace them.

I have always avoided the primary side of power supplies so perhaps it is time for me to get a new power supply. Any suggestions on how I can get one for a reasonable price? Weaknees seems a little too expensive for me because I live in Hawaii so shipping is going to add up. Perhaps eBay or do you guys sell refurbished power supplies?

Thanks

_____________________________________________________________

If yes test the diodes on the bottom of the board first. If your not sure how to make sure your on ohms and put the red lead on one side then put the black lead on the other side look at your reading then reverse the leads and see if you have ether high on way and low the other. If you get the same readings both ways it's most probably a bad diode. Also test the one on top side as well. If you was a little closer I could help you out but S&H is going to hurt. If you can't fix it look on eBay I have seen a unsubed for 20 bucks. If you go that route please don't trash the old supply it can be fixed. Do you see any burn marks on the board even a light one? 3amps is about 350 watts being a old ham radio oper it a lot less money to hookup 3 100w bulbs as fuses. If you get the forth of July you or going to have to pull the Xformer and ohm out the input and output check for shorts. Make sure you check the inductor it looks like a resistor but it's green and has 5 bands on it. Check all the resistors as well. They have two Shockley Diodes on the heat sink but I have never seen one fail. Keep in touch and let me know how it goes. Tim in La.

 

[unitron]

As expected the fuse immediately blew when I replaced it. I removed the MOV and tested the resistance and it is open loop so does that mean it is bad or that the resistance is infinitely high because there is no AC current applied?

I also took a look at the zener diodes and they look ok visually but they are so tiny I can't really remove a lead to test nor do I think I could replace them.

I have always avoided the primary side of power supplies so perhaps it is time for me to get a new power supply. Any suggestions on how I can get one for a reasonable price? Weaknees seems a little too expensive for me because I live in Hawaii so shipping is going to add up. Perhaps eBay or do you guys sell refurbished power supplies?

Thanks

A Metal-Oxide Varistor (variable resistor) is supposed to have very high resistance, so high that it reads as if it were "open".

That only changes when there is a "spike", that is, a very high difference in electrical potential, a very high voltage, between the two places where it's connected, which is usually across the AC line.

120V AC actually varies (60 times per second) from 0 Volts up to about 170 Volts and then back to 0 and "down" to about 170 Volts but with polarity reversed from the first half of the cycle.

Only if something, like lightning somewhere vaguely nearby, for example, puts a spike up above say 300 Volts or so on the line does the MOV suddenly become extremely conductive, essentially shorting that higher voltage to ground at which point the MOV becomes very "resistant" again until the next spike comes along. The spikes are much shorter in length than either half of a regular AC cycle.

Generally a spike isn't strong enough to push much current, but the much higher voltage will burn out semiconductor junctions and that's how it does damage.

If you get a strike near enough that you wind up with scorch marks, that's not what I'm talking about, and that's something that the MOV wouldn't have been able to prevent.