Help with Panasonic TC-P42ST30 After Power Surge


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Help with Panasonic TC-P42ST30 After Power Surge

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milkrocks
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Sep 24, 2012, 12:11 PM

Post #1 of 8 (2640 views)
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Help with Panasonic TC-P42ST30 After Power Surge	Can't Post

First off, thanks for your help! I've been working with electronics for many years now but have limited tv repair experience. I was given a TC-P42ST30 that wouldn't turn on after a power surge. I've replace the main board and the power supply. The TV will now power on with either the new PS or the one that came with the TV. All functions of the TV work properly including menus and inputs. The sound work perfectly.

The problem is in the image. The image shown is consistent with the program but the picture quality is terrible. Dark portions are black, light portions are completely blown out. The power supply is putting out 214.9V. This is true for both of the power supplies i have on hand. Adjusting the voltage up or down a bit has no impact on the picture (or at least it remains as terrible).

I'm thinking of buying one or both sustain boards but am not sure if this would correct my problem.

N9ZN
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Apr 18, 2014, 11:21 PM

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Re: [milkrocks] Help with Panasonic TC-P42ST30 After Power Surge [In reply to]	Can't Post

I am having the exact same problems with my TV. It is the same model, replaced the A (main) board to get it to power up and function again but my image is exactly like yours. I did not replace the power board or any sustain boards. I may be headed in that direction soon if I can not get this set working right as is.

Please give this old US Marine a little help here, I need my TV. It is in fact my best friend since I can no longer work and am pretty much home bound most of the time.

flyatyou66
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Apr 19, 2014, 1:33 AM

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Re: [milkrocks] Help with Panasonic TC-P42ST30 After Power Surge [In reply to]	Can't Post

Did you check your ribbon cables to make sure they work? Hold a flashlight to the bottom side and move it back and forth while watching top side. This will show any defects on the cable. You can also do a continuity test with a multimeter.
If that is good i would start looking at the t-con board for failure..It handles the colors plus puts them in there proper place, and gives you a good picture. Check if there is a smd fuse on the board

jts1957
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Apr 19, 2014, 2:39 AM

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Re: [flyatyou66] Help with Panasonic TC-P42ST30 After Power Surge [In reply to]	Can't Post

Quote

plasma tv's have 'tcon' boards? Shocked

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Apr 19, 2014, 2:50 AM)

xgc12
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Apr 20, 2014, 2:51 PM

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Re: [N9ZN] Help with Panasonic TC-P42ST30 After Power Surge [In reply to]	Can't Post

Need to take some readings on the boards to see if they are within value. Do you own a multimeter and feel comfortable taking voltage on a couple of boards?

Owner Atlantic Audio & Video
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N9ZN
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Apr 21, 2014, 9:48 AM

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Re: [xgc12] Help with Panasonic TC-P42ST30 After Power Surge [In reply to]	Can't Post

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Need to take some readings on the boards to see if they are within value. Do you own a multimeter and feel comfortable taking voltage on a couple of boards?

I agree values are essential when repairing anything electronic.
As it looks for now I need to swap the FLASH IC's, one or two of them, so the values for my set for my TV are re-established on the replacement board that came out of a different model and size TV set.
I have also ordered another replacement board made specifically for my model of TV, never hurts to have a spare handy for the next time lightning come through the cable box. Sadly that happens a lot in Tampa, Fl.

I have yet to confirm this but I believe my problems come from using a main board from a different model and SIZE TV. The FLASH settings on the replacement board are not correct for my Plasma Panel and the data copy function Panasonic provides for board replacement does not copy and re-write this information.

I will try to remember to come back and confirm this information, just in case anyone else has this problem and find this post while searching. I would bet, if the OP came back to comment, that he/she also used a replacement board from a different size or model of TV set. I have noticed on Ebay many sellers have told buyers main boards from various sets will also work with their set, sadly this information may not always be correct including when the manufacturers part number is the same for both main boards. I forgot to check for compatibility when I got the replacement board and went by mfg. part number leaving me also guilty of this error.

(This post was edited by N9ZN on Apr 21, 2014, 9:56 AM)

xgc12
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Apr 21, 2014, 9:08 PM

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Re: [N9ZN] Help with Panasonic TC-P42ST30 After Power Surge [In reply to]	Can't Post

Do you happen to have the part number for the main (A) board that you installed? I am only aware of one main board that will work with your 42" panasonic. As far as flashing ic's, are you talking about flashing the eeprom on the mainboard?

Owner Atlantic Audio & Video
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N9ZN
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Apr 22, 2014, 2:05 AM

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Re: [xgc12] Help with Panasonic TC-P42ST30 After Power Surge [In reply to]	Can't Post

The non standard replacement board i am using is from a 65 inch Panasonic model TC-65PST34. The Mfg. board part number is of this board is TNPH09121A with a suffix of "AH" and a Panasonic part number of TXN/A1NXUUS. The reason I tried this board is because only the Mfg Part number suffix differed from my original main board having a suffix of "nil". Both boards have the same identical Mfg. board part number TNPH09121A.

Just to be sure all is well with my TV I recently ordered another replacement main board, Panasonic part TXNA1PEUUS, for my specific model of TV a TC-P42ST30 built for the United States. My plans are to use the correct main board installed in the set except for a period when I will test and verify the use of the non standard board from the 65 inch TV after IC's have been swapped onto it from my original main board that was damaged by lightning. The IC's I am swapping are the flash IC's near IC 9300 and IC 8000 control circuits, IC 9304 is one of those chips that will be swapped and I do not recall off hand the numbers of the others. I will be doing them one at a time, testing after each swap, and stop when testing is verified as good/normal for the TV. I DO NOT PLAN TO FLASH ANY CHIP, INSTEAD I AM SWAPPING CHIPS PREVIOUSLY FLASHED FROM THE BAD MAIN BOARD TO A GOOD MAIN BOARD.

You can locate the placement of the chips I will be swapping by looking at the main "A" board, block diagrams for the TV-P42ST30 or TC-65PST34 in the television repair manual for these sets.

Hope this clears up my plans for you, if not let me know and I'll be happy to try to explain differently.

(This post was edited by N9ZN on Apr 22, 2014, 2:09 AM)

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