Toshiba 46RV530U TAC0802 has no voltage at main filter cap

[triplefour]

so i got this TV from the recycle place for 15$ and i noticed that i dont see any voltage at the main filter cap, and of course no voltage anywhere else either. there are 2 fuses, they are both good but i see no voltage on them. i see 120v AC right where the plug connects to the board but at the components right around there (a couple capacitors and a resistor) i dont see anything. not sure what else to check.

correction: i guess i AM seeing voltage at the main filter cap but only like 1.5v
and im seeing max 2v on any other components.

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

This PSU is in two parts - a SUB power board for standby usage mainly, and a MAIN power board.
What do you measure on AC volts across yellow wires going to upper power board in this pic?
https://www.badcaps.net/forum/attach...0&d=1409557915

[triplefour]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

ahh yeah i thought there was something weird about this PSU being in 2 pieces...
so i get 124VAC on those wires...

and i get 150VDC on the filter cap on that board.

and im seeing 3.8v on everything thats supposed to be giving me 5v, 12v, 18v or 24v

so im not getting 5v standby for some reason...

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

OK, see if the 3.8V rises to 5V when you unplug the connector going to the main board.

[triplefour]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

now its 11v on everything...even on the pins labeled ground...
im using the negative leg of the main filter cap as ground ref.

i plugged the motherboard back in but its still 11v everywhere.. idk what happend to the 3.8 and why anything that should be a ground is reading 11v!

also i noticed the main filter cap is still at 86v after being unplugged for 10 minutes

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

im using the negative leg of the main filter cap as ground ref.

When measuring output voltages you use the CHASSIS as your ground reference only.

[triplefour]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

ahh dang..u dont think i messed anything up by doing that do u?

[triplefour]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

ok well i have the board unscrewed from the chassis so i could flip it over to take measurements, so i used one of the pins labeled gnd on the connector as the ground reference and i come up with 0v on everything. the little bridge going to the other board, and the connector going to the main board...

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

No, but you will have to measure again.

[triplefour]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

i did measure again and everything is 0

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

OK please provide a close and in focus image of the top sub power board. Need to be able to see component ref numbers like C123.

[triplefour]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

i really need to get a better camera... if this still isnt good enough i can try harder

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

Need the top side too.

[budm]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

The main power supply will not get AC feeding the bridge until the main board turns on that black relay of the main power supply board, the relay is by the two yellow wires.
http://www.shopjimmy.com/toshiba-750...wer-supply.htm

http://www.shopjimmy.com/toshiba-750...wer-supply.htm

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

Yes, I think the sub power supply (yellow wires) runs all the time, main power supply switches on when relay is turned on.

[budm]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

He needs to find out if he can hear the relay clicks on or not, if not then he needs to find the PS_ON pin and verify the DC voltage when TV is OFF and when power switch is activated.

[tom66]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

No output from sub supply at the moment, it appears, so I think that is where to look for the fault.

[budm]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

Ok, I see that now in post 3.

[triplefour]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

i was using the wrong ground ref in post#3
when using GND pin as ground i get zero volts on all other pins (the connector going to the mainboard, and the bridge connecting the two power boards)

i cant seem to find any pin that says PS_ON
a lot of the connectors are unlabeled.

gotta try find a service manual or schematic?

the shopjimmy pictures are better than i could ever take with my camera....

too bad they dont have the underside of the bigger PSU board

[budm]

Re: Toshiba 46RV530U TAC0802 has no voltage at main filter cap

How about on that 5V1 on that small black connector?

P/N of Q880?
"and i get 150VDC on the filter cap on that board." This voltage at the two legs of the main filter cap seem low also, at 124VAC input to the bridge, I would expect at least 170VC.