Re: Please help me fix my beloved Panasonic TC-P65ST30
Just a PSA, that I did end up fixing my TV, but DO NOT BUY parts from TV Parts Today or [url]www.tvpartstoday.com[/url] . They sold me a defective PSU board and it took me an extra month of troubleshooting and buying additional parts to figure this out. Pay more and buy from a competitor that actually tests their boards before sending them out.
Thanks again Davi.p for all the help!Re: Please help me fix my beloved Pa... NOT BUY parts
Ren01
Member
Last Activity: 01-06-2022, 12:03 AM
Joined: 08-30-2021
Location: BC
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Plot twist, I ordered a replacement board from TV Parts today and the TV still won’t turn on! New board is exhibiting same issues and I’m stumped!Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
VCC is seeing 143 ohms between it and source pin, but only in one direction so I'm guessing diode....Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
The transformer is also not receiving any voltage on the other side, and that seems to be connected to a relay on another board that I cannot tell if it is faulty. This is going over my head.Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Just a side note, VCC is at 0 volts, and I have confirmed there is 120 volts going to the main power board.
It seems the transformer connected to VCC is also putting out 0 volts :/Last edited by Ren01; 10-24-2021, 06:23 PM.Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
I traced VCC back to these components, do they look bad? In circuit d407 is measuring very high resistance both ways. D404 measures around 200 ohms one way and very high the other. I also can’t read the labels at all....Last edited by Ren01; 10-24-2021, 12:40 PM.Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Thank you for that tip! Using one probe on on the leg of d412 which is shorted with the drain and another probe on the heat sink I’m getting 0 volts DC or AC. Similarly, the source is also 0 volts.
Would this mean the issue is the mosfet isn’t being fed VCC?...Last edited by Ren01; 10-24-2021, 11:37 AM.Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Sorry it took so long to reply, life kept me busy. No short from drain to source and double checked all pins soldered correctly. Not sure I can check the voltage while plugged in with my cheap meter safely. Since drain pin is right above the heat sink, it would be easy to short. I could buy a replacement resistor on my next order instead....Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
So, new mosfet from China arrived with new caps from digikey. Replacements parts were soldered in, but still no power at all
Maybe it's a fuse?...Last edited by Ren01; 09-15-2021, 04:39 PM.Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Thank you!!!...Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Source to ground resistance measures at 0.9 Ohms. My meter when touching the two probes together measures at 0.7 Ohms....Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
The capacitor that blew up was between the source and drain. Could that be it?...Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Definitely don't want a fire! What do you mean by shorted mosfet? When I removed the old mosfet, drain and source was shorted on it. Should I do more than replace the mosfet?...Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
I think I found the resistor you mentioned, but previously you said it wasn't it? Can you please confirm. I've attached the following:
1) The data sheet example circuit showing there must be a resistor attached source, R2
2) The example value of R2
3) A picture of the ceramic capacitor that I think is R2 (can't measure it well resistance too low)
4) A picture of the opposite side of R2 facing the side where the ceramic capacitor blew up showing a slight black mark.
5)...Last edited by Ren01; 08-31-2021, 05:29 PM.Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Thank you! The mosfet originally had no thermal grease or thermal pad, I wonder if that's what caused the failure...
Anyways, the round resistors on the top of the board, (didn't check the surface mount on the bottom) seem to measure fine.
I guess all I can do is wait for the new mosfet to arrive in 2-3 weeks. Thank you again for all the help! I'll report back if the repair is successful or not then....Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Would it be stupid to place some Arctic MX-4 thermal grease (non conductive) between the mosfet and the heatsink?
Sorry, I have so many questions!Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Looking closer at the pcb, I think c411 is in parallel with the ceramic resistor Davi.P mentioned. That would explain the short right?Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
Which capacitor value isn't critical? C404 or c411, thank you!...Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
There is a ceramic resistor beside the blown capacitor around 0.32 ohms. It seems to still be good, but my multimeter is not accurate enough to say for sure.
I had to guess the blown capacitors value by comparing the size of what was left with the rest of the capacitors on the board. Not very scientific haha....Last edited by Ren01; 08-31-2021, 08:19 AM.Leave a comment:
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Re: Please help me fix my beloved Panasonic TC-P65ST30
This diagram from the data sheet has me second guessing c404’s capacitance which I guessed as 471pf and 1kv when it is 100pf 2kv in the diagram :/ someone in a previous YouTube comment said it was 330pf at 1kv...Last edited by Ren01; 08-31-2021, 12:24 AM.Leave a comment:
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