Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

[JoeyB]

This is my first request for help here, so I hope I'm following the rules, and my apologies if I err.

My 2010 Panasonic TC-P54S2 plasma TV worked perfectly until one day it suddenly would not turn on. The power light would blink ten times. I tried various would-be fixes, such as (1)unplugging all the cables and letting it sit for a while, and (2)holding the power button down. The service manual said that 10 blinks indicates the power board, the A board, the SC board, or the SS board.

I replaced the power board--no change, still 10 blinks. I replaced the SS board--no change, still 10 blinks. I replaced the SC board, and it still wouldn't turn on, but it changed to 7 blinks. The manual said that 7 blinks indicates the SU or SD board.

This time, I dug out a meter and tested the cables to the SU and SD boards, and they all checked out. Since the SU and SD boards were relatively inexpensive, I ordered both and replaced both--no change, still no power and still 7 blinks.

I am a novice at television repair, and at this point I have no idea how to proceed. Seemingly the SC board was one problem, but obviously I still have another. Any suggestions would be greatly appreciated. Thank you to all who have read this far.

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Crikey, you've been around the block with this one. If only you'd been fortunate to come here first.

Do you still have the original SC board?

[JoeyB]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Yes, I do--

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

A few things may have happened here. I would almost put money the Sc being the original fault. There's a possibility the replacement Sc is also faulty, also a chance the original SD/SU boards were shorted and damaged the replacement SC but generally they survive but i have had one with SD & Sd shorted and it blew up a new Sc board.

I think it would be handy to resistance test the original SD/Su boards too.

How good is your multimeter? Can it get to 6meg ohms ?

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Yes, I do--

On the original Sc board,

measure resistance across the Sc2 connector pins, could show a few hundred K ohms or go 2-3 meg

near the Sc20 connector there is a test pad TP82, measure resistance between that and any gnd pad on the Sc board, could be 1350 -1500 ohms

across C561, also nesr Sc20, small ceramic SMD cap, resistance across that 5.63k.

[JoeyB]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

I'm not sure (about my multimeter). I'll have to check it out tomorrow--it's late here and I need to get to bed. Thanks a lot for the responses!

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Ok, well bummer for me, I'll post up some other checks but a quick check at this point would be to do the SC50 jumper test which involves isolating the SD/SU boards and firing it up but I think it may be useful to gather other evidence to ascertain whether anything else is bad first just in case it was a dud and you can get your money back on it.

So if the old buffers prove good and the replacement buffers prove good then we can assume replacement SC was bad if in fact it proves to be bad.

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

On the original Sc board,

measure resistance across the Sc2 connector pins, could show a few hundred K ohms or go 2-3 meg

near the Sc20 connector there is a test pad TP82, measure resistance between that and any gnd pad on the Sc board, could be 1350 -1500 ohms

across C561, also nesr Sc20, small ceramic SMD cap, resistance across that 5.63k.

Once you have this data, repeat on the replacement board, disconnect Sc20 ribbon and SC2 lead first.

Then on the original SD/SU boards measure the following pins, this is with the boards disconnected from the SC and disconnect the small ribbon that interconects SD/SU boards.

SU41

All are in respect to - Vfg(floating gnd, the metal plate the bolt goes through)
pin 2, or TPSU15 (VFO) 2.2Meg
pin 4, TPSU16 (VSCN-F (TPSC1)) 221K
pin 8, TPSU17 (5V_F) 5.7Meg

SD42

pin 1, or TPSD29 (VFO) 2.2Meg
pin 2, TPSD28 (VSCN-F (TPSC1)) 221K
pin 6, TPSD26 (5V_F) 5.7meg

repeat for the replacement SD/SU set you got

The G20,25 guide will be mostly applicable as the 5081 SC board is used throughout that series. slide 43-44 buffer tests

[vinceroger69]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Just read this post as joeyb has changed a lot of boards already whilst fault finding would it be best to replace all the boards with the original set ones? just incase some of the new boards have intermitant faults etc that his old boards wouldnt of had? or may even be slightly diffrent part numbers etc.

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Just read this post as joeyb has changed a lot of boards already whilst fault finding would it be best to replace all the boards with the original set ones? just incase some of the new boards have intermitant faults etc that his old boards wouldnt of had? or may even be slightly diffrent part numbers etc.

I think establish evidence first before we go ripping things in and out again. SC is most likely suspect and not too hard to prove bad if they've failed in the typical manner.

We could just go straight to Q661 and check for short But I like to see what's happened to the 5v,15v and vsus lines.

[vinceroger69]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

yes true i guess it could cause unnecessary damaage by keep swoping boards around.

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

yes true i guess it could cause unnecessary damaage by keep swoping boards around.

Just reading the first post, his first change was at the SC board swap but 7 blink, pretty much confirms bad SC. From there

a good SC + bad buffers = 7 blink
may now be bad SC + bad buffers = 7 (bad buffers killed good SC)

then replace with good buffers but Sc now bad = 7

or used Sc was originally bad and 7 blink but both sets of buffers should still be good.

If used was supplied bad, get refund and send original to modulinkpts, confirm both sets of buffers good, sell spare set.

All depends on what we can prove but I personally would not mess with that used SC applying power yet.

[JoeyB]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Thanks a lot for the responses, and especially for the troubleshooting guides. I'm just logging in quickly from work now, and will look more closely later.

Thanks again!

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

yep, and i'm logging out of breakfast for work. LOL

[JoeyB]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

I've got a lot of information to sift through here, so I may not post again soon, but I will report back. Thanks again to tw2005!

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

I've got a lot of information to sift through here, so I may not post again soon, but I will report back. Thanks again to tw2005!

Sure, yes it may seem a lot but I'm sure we'll get this on track again and narrow it down. This way we'll be sure .

[JoeyB]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

How do I spot the ground pads? I was hoping they'd be labeled, but no.

Thanks.

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

How do I spot the ground pads? I was hoping they'd be labeled, but no.

Thanks.

for the buffers it's where the large bolts came out of, can't miss the metal plate. pretty sure if you read what i've posted i've stated this .

[JoeyB]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Sorry, I meant on the SC board. I should have been specific. The holes for the bolts look different on it, but I guess it's the same answer. Thanks.

[tw2005]

Re: Panasonic TC-P54S2 plasma TV--won't turn on, originally 10 blinks, now 7 blinks

Sorry, I meant on the SC board. I should have been specific. The holes for the bolts look different on it, but I guess it's the same answer. Thanks.

almost, any point the bolts mount that has metal contact will do except where the buffers mount which is floating gnd not chassis.