Sony KDL-32EX340 not powering on

[budm]

Re: Sony KDL-32EX340 not powering on

That is means the PFC is working and the STBY power supply is also working since the VCC for the PFC IC is from one of the winding output of the standby power supply. I think he need to choose which board to work on first, the old one with dead STBY, or this one with PFC and standby working, also since he indicated that the 380V on the cap drops down, then he needs to verify that it is not due to PS_ON drop off.
The small red circle is after the fusible resistor R6536 that feeds the B+ from the + of the main filter cap to the two power MOSFET for the 12V-24v SMPS section.
BTW, that big SMD IC in the primary side is the PFC Controller and SMPS IC all in one.

[OldMan]

Re: Sony KDL-32EX340 not powering on

looks like he is getting the 380 between neg of main cap pin (yellow) and the small red circle w/ + next to it on the main power mosfet

This is correct. Main cap is a steady 164V.

What can I conclude from this pertaining only to the newest board which doesn't show open with respect to pin 7 of the IC? I'm pretty much stumped and the shop I bought the board from stands by their word of testing the board prior to shipping.

[budm]

Re: Sony KDL-32EX340 not powering on

You should be getting 380V on the large red circle also since those two red circles are connected through very low Ohms fusible resistor R6536.

[bammbammfran]

Re: Sony KDL-32EX340 not powering on

I agree that the voltage at the main cap and power mosfet pin should be basically identical since the white resistor is only .1ohms

Discharge the board again and Try checking that white rectangular resistor

also while checking resistance
check the red circled pin versus the black circled pins on the capacitor that I had you check for 12 volts

[selldoor]

Re: Sony KDL-32EX340 not powering on

Lost me several times! I did ask him to choose a board to work on and ONLY
refer to that in the thread.
I think given that you at least have standby on the new board going forward
ONLY work on that and try to establish if the mainboard is working ok.
Which I believe is what Budm is saying.

[OldMan]

Re: Sony KDL-32EX340 not powering on

Ok, focusing only on the new board as this seems to have fewest issues.

Budm, what large red circle should have 380V in your picture? I can test but don't want to test wrong spot and short something. Imagine I keep negative on the negative of the big cap still?

Bamm, no resistance on the 12v cap

[budm]

Re: Sony KDL-32EX340 not powering on

Just measure right at the two legs of the big filter cap when TV is plugged in and when the power switch is activated.
When measure the voltage on the secondary side you will use chassis ground as the ground ref point such as the 5VSTBY, 12V output on the secondary side. When work in the primary side, the negative leg of the main filter cap is the ground ref point.

[bammbammfran]

Re: Sony KDL-32EX340 not powering on

Bamm, no resistance on the 12v cap

NO resistance on the cap OR shows as Zero ?
It should build up resistance, or if partly charged may drop and then raise back up
If Zero, it is shorted at the rectifier diode
If not showing Zero, and if using a manual select tester, raise up to the next ohm setting

[renee]

Re: Sony KDL-32EX340 not powering on

please help me to find volts PRI_VCC on C6206 sony G6 power supply