TC-P55GT30; test SU/SD board procedure

[Logan_c]

I am getting my SC board repaired, however I would like to know the procedure to test the SU/SD buffer boards so that I don't end up frying the SC board.

I did the continuity short test down all 10 (5 ribbon connectors per board) on both sides, and originally I had a short (replaced the IC601/2), and since then I no longer get a short when I do the same test, however is there more/other test I should do on those buffer boards?

[tw2005]

Re: TC-P55GT30; test SU/SD board procedure

I am getting my SC board repaired, however I would like to know the procedure to test the SU/SD buffer boards so that I don't end up frying the SC board.

I did the continuity short test down all 10 (5 ribbon connectors per board) on both sides, and originally I had a short (replaced the IC601/2), and since then I no longer get a short when I do the same test, however is there more/other test I should do on those buffer boards?

good job if you just did a buffer rebuild. Done a couple myself, very satisfying also very challenging. was it the SU top 2 chips?

[Logan_c]

Re: TC-P55GT30; test SU/SD board procedure

tw2005,

It was the top two chips indeed! I work with electronic repair techs as part of what I do, so they did the replacement.

Because I had attempted a repair with a shopjimmy kit on my SC board, and it was unsuccessful, I sent it off to someone for a repair, plus an additional charge because it no longer had the original components. The shopjimmy kit had a bunch of diodes, IGBTs and an IC or two for the SC board and those were different than the original components. I bet there were other bad parts on the SC board and I don't have the chops to test for that, so off it went.

Since I'm about $150 into this repair I really don't want to plug the SC board in and have the tv not work. Hence my concern with testing the SU/SD boards.

I'm not sure what's left to test before i power the set up. Or what is left to be wrong if it doesn't work so I am open for other ideas.

[tw2005]

Re: TC-P55GT30; test SU/SD board procedure

tw2005,

It was the top two chips indeed! I work with electronic repair techs as part of what I do, so they did the replacement.

Because I had attempted a repair with a shopjimmy kit on my SC board, and it was unsuccessful, I sent it off to someone for a repair, plus an additional charge because it no longer had the original components. The shopjimmy kit had a bunch of diodes, IGBTs and an IC or two for the SC board and those were different than the original components. I bet there were other bad parts on the SC board and I don't have the chops to test for that, so off it went.

Since I'm about $150 into this repair I really don't want to plug the SC board in and have the tv not work. Hence my concern with testing the SU/SD boards.

I'm not sure what's left to test before i power the set up. Or what is left to be wrong if it doesn't work so I am open for other ideas.

Well there's probably a few ways to go about it but I'd just go diode mode and check there's no shorts between te gnd plates and the outputs keeping in mind there's pins on both sides of that latch.

Check for no shorts and also you'll find if you have it in diode onw way should give a reading around 0.7 you could check each pin has a reading just in case a leg has not soldered but I guess you probably covered the IC with sealant by now.

That's all I've done and it's proven to be reliable, even found a pin not soldered this way.

[Logan_c]

Re: TC-P55GT30; test SU/SD board procedure

I got my SC board back from being repaired and the good news is that I have a picture. However I have two black horizontal lines that seem to stem from the 2nd from the bottom ribbon cable.

Those 10 ribbon cables are very finicky to insert and seat properly and many times I would have many, many black lines, then I would reset the cable and sometimes more black lines, sometimes less. Eventually I reset enough ribbons that I had just the two black lines left, both very near each other. I retested the SD board, running my voltmeter ohm and continuity and could not find a short.

The two black lines appear to be at the ribbon cable's first and last scan lines. This is also the 9th one down, right behind the volume/channel selector. I finally removed that volume selector unit to get better access to the ribbon connector.

Any thoughts on what may be the problem? Or what to test?

[syaoran123]

Re: TC-P55GT30; test SU/SD board procedure

Seems like you are not seating the ribbon cables correctly. I never had a problem reseating them.

[tw2005]

Re: TC-P55GT30; test SU/SD board procedure

I got my SC board back from being repaired and the good news is that I have a picture. However I have two black horizontal lines that seem to stem from the 2nd from the bottom ribbon cable.

Those 10 ribbon cables are very finicky to insert and seat properly and many times I would have many, many black lines, then I would reset the cable and sometimes more black lines, sometimes less. Eventually I reset enough ribbons that I had just the two black lines left, both very near each other. I retested the SD board, running my voltmeter ohm and continuity and could not find a short.

The two black lines appear to be at the ribbon cable's first and last scan lines. This is also the 9th one down, right behind the volume/channel selector. I finally removed that volume selector unit to get better access to the ribbon connector.

Any thoughts on what may be the problem? Or what to test?

patience, persistence and focus are the only tools you need.

Don't get sucked into running the TV and adjusting or else

[Logan_c]

Re: TC-P55GT30; test SU/SD board procedure

Can it be assumed that there are 1080 horizontal lines on the panel, and I can then count up how many lines from the bottom to know exactly which ribbon cable is at fault?

If there are no shorts can it be assumed that the issue is soley not being seated properly, or could there be some other issue?

[tw2005]

Re: TC-P55GT30; test SU/SD board procedure

Can it be assumed that there are 1080 horizontal lines on the panel, and I can then count up how many lines from the bottom to know exactly which ribbon cable is at fault?

If there are no shorts can it be assumed that the issue is soley not being seated properly, or could there be some other issue?

The lines will line up directly to the offending ribbon, no need to count anything.

If the buffer was shorted the TV would be off and 7 blinks , and potentially damage the SC.

These can be hard to get right especially in the really thin models. Touch wood I've not had to touch the sd/su on one of those yet but I would struggle.

[Logan_c]

Re: TC-P55GT30; test SU/SD board procedure

Could it be possible that the ribbon cable is damaged. This is that cable that is difficult to get to as it is positioned behind the volume controller. I did make several attempts at reseating this before finally removing that part to get better access. If I had damaged the cable would the lines be the result, or are horizontal lines always caused by poorly seated ribbon cables?

[tw2005]

Re: TC-P55GT30; test SU/SD board procedure

Could it be possible that the ribbon cable is damaged. This is that cable that is difficult to get to as it is positioned behind the volume controller. I did make several attempts at reseating this before finally removing that part to get better access. If I had damaged the cable would the lines be the result, or are horizontal lines always caused by poorly seated ribbon cables?

lets hope not. If you've torn it or damaged it then game over.

You should be able to see if it is, Compare the alignment to the ribbon next to it.

Keep trying. How do you have the TV positioned? Is it awkward to work on or is it laid flat on a table and you're sitting down?

[tvtimmy]

Re: TC-P55GT30; test SU/SD board procedure

Keep at it! Make sure you unplug it before re-doing them. Re-fit them, turn it back on and check. I have had pretty good luck with su/sd boards, and had a bitch of a time with the 42" models that have an all in one SN board.