Sanyo FW42D25T

[R_J]

Re: Sanyo FW42D25T

What is the top marking on the ic? what is the vcc voltage?

[nomoresonys]

Re: Sanyo FW42D25T

Thanks gentlemen, any way to verify UB101 is not working, like testing QB101 or DB106? QB101 has 170 v on middle pin, 0 v on the other two, DB106 tests good in diode mode, has 170 v on each end.

[lotas]

Re: Sanyo FW42D25T

not sure, is that ic on the primary/hot side? I don't see any ic on the hot side.

Remove the heatsink and you will see UB101 PWM (6pin.).

[R_J]

Re: Sanyo FW42D25T

It is on the primary side. There will be a small driver ic, likely a smd 6 pin, this ic drives a power mosfet that switches the primary of the main transformer to produce the secondary voltages.

[nomoresonys]

Re: Sanyo FW42D25T

not sure, is that ic on the primary/hot side? I don't see any ic on the hot side.

[R_J]

Re: Sanyo FW42D25T

For the primary smps ic to operate it first needs vcc voltage, what do you measure on the vcc pin of the ic?

[nomoresonys]

Re: Sanyo FW42D25T

.

[nomoresonys]

Re: Sanyo FW42D25T

oops I lied, there is 170 volts on 2 pins of the transformer on hot side.

[nomoresonys]

Re: Sanyo FW42D25T

Only getting voltage there, only millivolts or 0 volts everywhere else, no voltage on cold side no voltage on any coil or cap except filter cap no voltage on UL1, UL2 or eeprom, maybe problem with transformer?:

[nomoresonys]

Re: Sanyo FW42D25T

didnt have a 10uf 50v cap handy for the orange cap, threw a 47uf 50v in there.

[nomoresonys]

Re: Sanyo FW42D25T

think the panel didnt crack but its no wonder, was working on a small table thats easy to get around, almost dropped the whole thing off of it. With tv plugged in to power, the only voltage I get is 170 on filter cap and voltage on the big diodes next to it, seems to be no voltage at any connectors, no voltage on UL1 or UL2, guess I'll try switching out a few more electrolytics, my gm328a cap tester tests m pretty good out of circuit but for shit in circuit, no choice but to guess, maybe switch out the 4 green samxon caps.

[nomoresonys]

Re: Sanyo FW42D25T

Thanks R J, I think I messed something up, I switched out those 2 caps, decided to put the screen back on but had a hard time fooling around with it, the whole frame seems to be really flimsy, might of cracked the screen not sure, instead of getting 30 seconds on, now I get nothing at all, not the first time I've gone in reverse trying to fix something.

[R_J]

Re: Sanyo FW42D25T

This is a link to a similar board

[nomoresonys]

Re: Sanyo FW42D25T

Thanks Lotus.

[lotas]

Re: Sanyo FW42D25T

what voltages I should be getting on UL1 and UL2?

3.3v, 1.8v.

[nomoresonys]

Re: Sanyo FW42D25T

ok, I'll change those out, thanks RJ.

[R_J]

Re: Sanyo FW42D25T

I don't believe this power supply has a pfc circuit, I would suspect the small vcc caps in the primary CB107, CB106? (the orange and black ones)

[nomoresonys]

Re: Sanyo FW42D25T

have one of these, had a slightly bulged 16 v 470 uf cap, replaced, tv will work ok for 30 seconds then it blanks out backlight and sound goes out, dont seem to be getting the boosted voltage at filter cap, is 170 when hit power button or in standby, wasn't getting backlights to light with tester, tore down to expose them, they all lit up wondering what voltages I should be getting on UL1 and UL2, in standby I guess, because it doesnt seem to want to stay powered up, maybe its a problem in the pfc section, not sure, any ideas?

[dskall]

Re: Sanyo FW42D25T

Ya read post 10

[Jsikora]

Re: Sanyo FW42D25T

I am hoping someone else has fixed this model as the PS is not available anywhere. Any idea of where to begin looking for problems on the board that would cause not getting 12V to LVDS?