Sony xbr65x900c sound yes, no backlight or image.

[vinceroger69]

Re: Sony xbr65x900c sound yes, no backlight or image.

This video is worth a watch
https://www.youtube.com/watch?v=zK8oNhFaRdM

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Thanks VR69 you

[vinceroger69]

Re: Sony xbr65x900c sound yes, no backlight or image.

Thanks VR69 you

so easy to forget how to test things at times even more so as i get older lol.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

I hear that, I'm sooo glad I didn't go into brain surgery, as fast as I forget things, I would've been turning all my patients into zombies.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

This is the beast I'm dealing with, sj pic: https://www.shopjimmy.com/sony-1-474...-supply-board/

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

BR is ok, in stby I get 165 on main filter cap, with 3-bl-on, 5-stby and 9 power-on jumped, it's 275, with just 5 and 9 jumped it's the same 275, here's a question, I know the boosted pfc is suppose to be around 400 volts, so I wonder if it's only 275 v. because I have a 450 volt main cap in for testing, where the ones I blew up and took out totaled 1140 v. or if I messed up the pfc when they blew up? or if I have to jumper still some other pin to get the boosted pfc voltage? thanks.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Which part number is the pfc transformer? is it T901? thanks.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

It's a a6069h, I think this is the equivalent: https://datasheetspdf.com/datasheet/STR-A6069H.html

Ok, on this IC901 three of the legs read short, beep in diode mode that is, I think only one is suppose to though, trying to figure this out bit by bit, trying to avoid taking the mosfets out of circuit, the designers of this board just HAD to make it as low profile as they could, which means torture for whoever has to deal with those mosfets.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

None of the fets test short from gate to source, in circuit.

[dskall]

Re: Sony xbr65x900c sound yes, no backlight or image.

BR is ok, in stby I get 165 on main filter cap, with 3-bl-on, 5-stby and 9 power-on jumped, it's 275, with just 5 and 9 jumped it's the same 275, here's a question, I know the boosted pfc is suppose to be around 400 volts, so I wonder if it's only 275 v. because I have a 450 volt main cap in for testing, where the ones I blew up and took out totaled 1140 v. or if I messed up the pfc when they blew up? or if I have to jumper still some other pin to get the boosted pfc voltage? thanks.

Trying to remember I had a problem with a TV, I believe was backlight problem. It had low PFC voltage. It had a string of resistors going to PFC controller which were out of spec. Replacing bad ones brought up voltage to 390 and fixed the problem.

Here is thread title. DYNEX DX55L-150A11 Randomly turns off

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Thanks Dskall, that makes perfect sense, I'll try to trace those resistors, I have that one zener diode ZD909 that reads short in circuit but is ok ooc, I'm almost positive that I checked it along with the rest of the 2 legged diodes before the main caps blew up and none read short in circuit.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

A little more on IC901, the BR pin is reading short, it seems wrong??: https://www.semicon.sanken-ele.co.jp...uct=STR-A6069H

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

There's a tiny diode D600 on underside of board that reads 99 both ways, seems strange.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Anyone know what could make the zener 909 read short in circuit but good ooc, I think I can solve this mystery if I can track this short down, pic. in post #85 IC901 tests good I think, 17 v on vcc and I'm getting the 275 same as the main cap on the start pin.

[Diah]

Re: Sony xbr65x900c sound yes, no backlight or image.

Plus when ZD909 is installed it reads short but is ok out of circuit, well .972 one way and 1 the other.

not good

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Ok, thanks, I'm gonna take that pos out and kill it again, LOL.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Crap my bad, it reads 848 out of circuit, there's seven more on the board they read 682, 704, 828, 799, 863, 676, 803 in circuit but don't read short on diode test.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Clipped diode, still getting short across the contacts.

[nomoresonys]

Re: Sony xbr65x900c sound yes, no backlight or image.

Tiny zener, how do I know what to replace it with, is there some tiny writing on it?

[Diah]

Re: Sony xbr65x900c sound yes, no backlight or image.

Crap my bad, it reads 848 out of circuit, there's seven more on the board they read 682, 704, 828, 799, 863, 676, 803 in circuit but don't read short on diode test.

for zener 676 / 704 are acceptable value .. mybe yours DMM drunk !!!