Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

[CleanSC]

Gentlemen:

Panasonic TC-P55GT30 with 7 blinks.

Using the 2011 Panasonic pdf, it seems my 7 blinks may be the A board.

Following the flow chart, after unplugging SC20 and C20, I still get 7 blinks. Which means P or A board. Checking the voltage on the next step says Replace A board.

Ok fine. But, everything I read has NEVER yielded an A board for this one.

So I'm here to verify.

I've done the Isolation SC50 check, and I get 8 blinks right after a quick buzz sound and instant shut down.

What's my next step to be sure it's either the SC/SD/SU or just the A board?

Thanks, fellas.

[tw2005]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

sounds a bit weird. are you sure you're pulling the right cables? SC20 is the flat white ribbon at the SC board, SC2 is the power cable from the P board.

Describe to me what you did for the SC50 test. SC2,SC20 connected, sd/su disconnected and there earth screws removed?

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Yep, I'm sure I've pulled the right cables. And I'm glad to see you guys think this one is strange too.

For the SC test I followed the procedure in the Service Manual, and also the one on in the 2011panasonic pdf.

Pull all ground screws on SU/SD and all connectors between each and the SC board. Jump SC50 and power up.

Sharp BUZZ, shut down, then 8 blinks.

If I put everything back together, it goes back to 7 blinks.

SC2 is also not shorted, and there's nothing visually bad on the 3 S boards.

I was at it all day yesterday and checked many things, including presence of the VSUS line which was fine.

I tried doing it the solo way with the manuals but it's not too convincing so I'm here ready to start from scratch.

Let me know what you think I should try next (or first, starting over)

Thanks for the direction!

[tw2005]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Yep, I'm sure I've pulled the right cables. And I'm glad to see you guys think this one is strange too.

For the SC test I followed the procedure in the Service Manual, and also the one on in the 2011panasonic pdf.

Pull all ground screws on SU/SD and all connectors between each and the SC board. Jump SC50 and power up.

Sharp BUZZ, shut down, then 8 blinks.

If I put everything back together, it goes back to 7 blinks.

SC2 is also not shorted, and there's nothing visually bad on the 3 S boards.

I was at it all day yesterday and checked many things, including presence of the VSUS line which was fine.

I tried doing it the solo way with the manuals but it's not too convincing so I'm here ready to start from scratch.

Let me know what you think I should try next (or first, starting over)

Thanks for the direction!

Was this your TV? You saw it working before 7 blinks? Cracked panel any chance? may have blown the buffers and now with bypass SS is detecting panel short?

Try this, leave the bypass in and follow the 8 blink flowchart and see where that leads. I'm thinking you have more than one failure

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

I acquired the tv after the failure. So I never saw it working. Panel looks visibly fine. No cracks that I have seen.

I'll do the bypass again and try the 8 blink chart. To clarify, I unplug/unscrew SD and SU and jump SC50 and trouble shoot as such?

Thanks!

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Tidbit from the manual:

"Note: Disconnecting SC20/A20 on the 2011 models
causes the TV to shut down with 8 blinks instead of
6 blinks like it was the case of the 2009 and 2010
models."

Not sure if that helps here but there it is nonetheless.

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

IGNORE THIS WHOLE POST: I WAS USING THE WRONG MANUAL. See post below. (It did power up during testing, tho)

Okay from the top, second round of testing:

Isolate SD/SU: Now have 6 blinks. (Before I said 8, I may have been confused or the result changed) Same buzz, then shut down.

Flow chart for 6 blinks: Unplug SC20 and C20. Now have 8 blinks.
Flow chart says if blinking, check 15v and 5v on SC board. SD/SU still isolated. Result: Both voltages good. Replace A board. End chart.

Next test: SD isolated. 7 blinks.
Next test: SU isolated. 7 blinks.
SD/SU isolated: 6 Blinks, See above.

Unisolate SD/SU. Back to factory setup. 7 blinks.

7 blinks flow chart: unplug SC20 and C20. Result: 8 blinks.

Follow chart for 8 blinks (SC20 and C20 still unplugged): Unplug SS33. Result. TV POWERS ON. Fans running.

Flow chart says next step is "Unplug the TV. Check for continuity between pins 1 and 2 of connectors SS61 and SS66 on the SS board . (Go to the previous slide to see picture of connectors location). Do not plug in the TV."

Uh, I don't have that connector on my SS board. The flow chart shows a skinny long board, mine is a wider rectangle. SS61 is printed on the board but there's nothing on it.

Hmm... that's not the first mismatching info I see in this manual since it's the ST30 one.

Any help on the next step to take? Is there a GT30 version of this troubleshooting manual? The factory one doesn't have blinking light flow charts like this one.

Thanks all! At least it powered up now, that's a first.

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Holy hell I just found the right manual for the GT30. I've been using the wrong one this whole time. No friggin wonder. Wow I feel dumb.

The flow charts are totally different so let me redo everything from the start:

GT30 7 blinks:

Vsus and VDA Short? No.
Check:
IC724 (VF_5V) = 472 ohms
TPSC1 (VFO) = 5 ohms

Are those numbers ok? The manual doesn't state exactly what "low" resistance is.

Assuming they are OK and you go "no short" on the flow chart:

Isolate SD/SU and turn tv on:
TV on? No. ---> Replace SC Board

If those numbers are bad then they go into seeing if it's SD, SU, or SS or all three SD SU SC.

So now, there you have it. Cut and dried SC board? Shall I test the D and U boards or anything else before I have the SC board fixed?

Thanks, all! Sorry for the confusion at the start. Ready for the next step.

[tw2005]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

TPSC1 (VFO) is shorted, next step would be isolate the sd and su from the SC ansd see if still shorted, if so the SC is shorted but you should still test the Sd/SU for short as they can go and then take out the SC.

What I'm not getting is since obviously there is a short on that side, why did you get 8 mblink with sc50 jumpered and sc2,20 connected.

feel free to upload the manual you used for everyone else.

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

I isolated SD and SU in the before test and no power again. So it points to SC board.

I got 8 blinks when I isolate SD/SU and unplug SC20 and C20. not SC2. C20, a ribbon on the bottom C board. This is a test for ST60, a result of my mistake of using the wrong manual. Shouldn't even apply to this set.

I've uploaded the manual below. I was assuming I was working with a manual that everyone else on here was using for this common issue but if not, great! I've contributed something. It's for VT30 and GT30.

So to be sure, VFO is measured off the legs of the big blue resistors? (They all read the same 5ish ohms.)

I followed the chart, unplugged the SU board and VFO went up to 400k ohms and dropping.

Says to replace all three because if SU is bad, the others are likely too.

Is there a definite test for these, and for the panel? Or is that it, send the boards off?

[tw2005]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

that's a guide i don't have. had the st30. yeah replace all 3 if Panasonic are paying under wty but not so sure it's essential. Could be just a precaution on their part for those techs who get it wrong and blow another SC board.

I've always gone about it like this. perform the sd/su isolation sc 50 test.that determines if the SC is bad .

Procedure:
1. Remove the 4 VFG screws from the SU and SD
boards. (See picture on the left side.)
2. Remove SC41, SC42, and SC46 from the SC
board. Also remove the ribbon cable between
the SU and SD boards (SU11/SD11).
3. Install the SC50 Jig or just jump pins 1 and 2 of
connector SC50 on the SC board.

If it powers with no blinks then sc is good , buffers need checking otherwise sc is bad and buffers still need checking.

SU41 pin 8 is Vfo

pin 2 is Vf5v

SD42

pin 1 Vfo
pin 6 Vf5v

isolate sd46,sd42 su41 from the sc board and at the buffer board connectors check resistance of the above with respect to the Vfg(gnd) plates on those buffer boards. usually Vfo will show short when a buffer fails. Sounds like the SU is shorted and I expect the 5 ohms.

If sc and su are bad then it may be just as safe to get that last board.

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Isolation test: Failed. 6 flashes.

SU41 VFO: 1.6 ohms

SU41 VF5V: 577 ohms

SD42 VFO: 786k ohms

SD42 VF5V: 580k ohms

Panasonic isn't paying for anything. I am. I purchased this set broken from the original owner.

Thanks! Looks like we're getting closer!

[tw2005]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Isolation test: Failed. 6 flashes.

SU41 VFO: 1.6 ohms

SU41 VF5V: 577 ohms

SD42 VFO: 786k ohms

SD42 VF5V: 580k ohms

Panasonic isn't paying for anything. I am. I purchased this set broken from the original owner.

Thanks! Looks like we're getting closer!

Ok, well if you have 6 blinks and sc50 was jumpered it's shot the SC, SU is shot and SD may be ok but Vfo is about half I expected but then i don't know what these should read but a 2010 board is about 1.8mohm for vfo - gnd.

You may have to go all 3 to be safe

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Sounds fine to me. For a set this nice and large it's worth just getting all three done to assure the repair.

What's the favorite repair outfit in the US? Moduslink? They are having a sale and all three boards SC SU SD cost $142US to fix.

I reckon that's not a bad deal at all.

Any other options out there?

Firmware upgrade is called for after the board repair, is that done thru wifi on this tv thru the OSD?

Thanks, fellas! So far on this site I've saved a handful of displays from the heap! Looks like this is another.

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Sent all three boards (SC, SD, SU) to Moduslink.

136 bux later, the TV fired up and is working great!

New screws, new firmware, dusted out cruddy fans.

Thanks, all! Another success story.

I bought this TV for $100. $236 all in after repairs. Not bad! Will be a great bedroom set.

[CleanSC]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Forgot to mention, now that it powers on, I got 4600 hours and 1500 power cycles on this unit.

About average for the age. Think I did pretty well. Should provide good service for quite a while.

[electronicsurplus]

Re: Panasonic TC-P55GT30 7 Blinks Diag Points to A board?

Great Job tw2005

Cheers