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Old 12-02-2021, 04:35 PM   #20
Join Date: Jul 2017
City & State: Braunschweig
My Country: Germany
I'm a: Knowledge Seeker
Posts: 57
Default Re: Panasonic TX-P50STW50 Power Supply no 5V (was clicking)

I am 100% sure that the 5V should come up without anything connected to the board.
Lets take a step or two back.
Last thursday I had the Powerboard over at may parents place for debugging with my dad who has way more knowledge in eletronics that I have (although he says he never understood modern power supplies).

We had the Powerboard on the desk with nothing but Main connected and finally found the faulty 2.2Ohms resistor. We didnt have the correct resistor at hand so we replaced it with a series of four... I forgot the values, must have been 0.5Ohms. Maybe slightly higher, because I remember we debated if we use 3 or 4.
Once that was in and Power was connected I had 4.6V on the output side of the voltage regulator and on the mainboard connector. And then when I connected 5V to Panel_Main_On, STB5V_ON and F_STB_ON the relay started clicking again.

I have a large box of resistors at my place so I assumed I should have a 2.2Ohm. I unsoldered the 4 resistors in series and took the board home.
After hours of searching through the box I realized I do not have a 2.2 at home either so I used 4 10Ohm in parallel.

Since then there has never been 5V on the output of the regulator.
It frustrates me to no end because I know it has been working and I didnt even change anyhitng (critical) afterwards
Ierwin is offline   Reply With Quote