RCA L32HD41 No power when inverter is connected

[philliesfan30m]

The power supply chirps around the transformer when the inverter is plugged in and i get no power at all on the secondary side except a small amount of pulsing voltage that coincides with the chirping but with the inverter disconnected i get all the proper voltages on the secondary side and the tv powers on and off like it should. So i am thinking the power supply isn't driving the transformer properly when it has a load or a short but i checked the caps,diodes,resistors, etc. and i can't seem to find a faulty part or parts that is causing it to shut down when trying to power the inverter. i don't get a flash of backlights and i did check the inverter board also and the fuse is ok and everything checks ok too. so i am sure it is something on the psu but am having a hard time finding it. thanks in advance for any help.

[budm]

Re: RCA L32HD41 No power when inverter is connected

Can you upload good clear pictures of the inverter board?

[philliesfan30m]

Re: RCA L32HD41 No power when inverter is connected

pics of inverter board from left to right looking at is as if it was connected. those 2 different caps are like that on other boards as well. the board was never touched as far as i know.

[CapLeaker]

Re: RCA L32HD41 No power when inverter is connected

Did you check the inverter board for a short? Sounds like the power supply shuts itself down, when the inverter board is connected.

[budm]

Re: RCA L32HD41 No power when inverter is connected

Just the inverter board by itself, check the resistance on the two legs of the those two filter caps to see if it shows low resistance, also check the resistance between the S and D of those 4 power MOSFETs.

[philliesfan30m]

Re: RCA L32HD41 No power when inverter is connected

well the 2 caps show just continuity it should be higher than that. with the 2 leads together i get about 1.5 ohms and between the leads of the caps is about the same 1.6ohms. 2 mosfets read the same between s and d 1.5 ohms and the other 2 read 95 kohms and 117 kohms those readings are from closest to the connector to furthest away.

[budm]

Re: RCA L32HD41 No power when inverter is connected

You have bad MOSFETs, the resistance between the two legs of the cap should in the 1000's Ohms range. Remove the suspected MOSFETs and test them off the board. all 4 should be replaced at the same time if you do find the bad one.

[philliesfan30m]

Re: RCA L32HD41 No power when inverter is connected

so you as saying remove all 4 and replace all 4 but when i remove them check them so i can find out which 1 or 2 or all are bad to use for someone else in case they run into the same problem? just for reference that board is a SSI320_4UA01 made by samsung which i saw was in a bunch of different brands and models.

[philliesfan30m]

Re: RCA L32HD41 No power when inverter is connected

i will do that and report back when tested off the board and thanks so far for the info it is greatly appreciated!

[budm]

Re: RCA L32HD41 No power when inverter is connected

Remove the suspected bad one first, if they are bad then I would replace all 4 at the same time plus the two caps. The 4 MOSFETs are set up as a bridge drive.

[philliesfan30m]

Re: RCA L32HD41 No power when inverter is connected

the mosfets on the board are could i replace them with these? they are both off inverter boards and seem to have the same or close to the same parameters and limits but i would like to know your opinion. if not i have other boards that i would rather salvage off rather than buy if i can.

[budm]

Re: RCA L32HD41 No power when inverter is connected

The sub will run hotter due to higher Rds and a lot poorer thermal resistance (Ja (Junction to Ambient) of the sub is 62.5 deg. c/W instead of 40 deg. c/W on the original). You can try them for testing.

http://www.daycounter.com/Calculator...lculator.phtml

[philliesfan30m]

Re: RCA L32HD41 No power when inverter is connected

ok thanks for the info. when i get them off the board and test them i will use one or 2 of those as a test piece to see if i can get it working. will report back with findings. i just wanna say thanks because i have seen you have helped solve a lot of troubleshooting with people here me included and you are very patient with people that don't have the knowledge of electronics like you do!

[philliesfan30m]

Re: RCA L32HD41 No power when inverter is connected fix

i replaced q106 + q107 and that got it to come back to life. Now i am gonna replace all 4 with the proper mosfets and replace those 2 caps like you suggested. Thanks again for the help i would still be troubleshooting the psu if you wouldn't of helped. And if anyone else has the same problem they now have a fix as well.

[budm]

Re: RCA L32HD41 No power when inverter is connected

Great news and thanks for the follow-up on the repair.