42PFL7406 No Power

[trunks81]

Hello

ive got an PFL7406 with power supply DPS-139AP looks like the PFC Boost wont start.
When Power supply connected to the mainboard iam getting these readings from the rectifier voltage changes from 290V to 315V and over the filter cap iam getting 390V to 410V
All the caps on the board have an good ESR tested with an Peak ESR 70

[budm]

Re: 42PFL7406 No Power

Hello

ive got an PFL7406 with power supply DPS-139AP looks like the PFC Boost wont start.
When Power supply connected to the mainboard iam getting these readings from the rectifier voltage changes from 290V to 315V and over the filter cap iam getting 390V to 410V
All the caps on the board have an good ESR tested with an Peak ESR 70

The PFC Voltage booster is working otherwise you will not have that 390V to 410V on the main filter cap, 410V is in the high side, the PFC boosted Voltage is in typical range of 380 ~ 400V, so is your meter is accurate?. BTW, the PS-ON from main board is also OK otherwise the PFC will not be running right now.
How about other Voltage on the power supply connector that goes to the main board?

[trunks81]

Re: 42PFL7406 No Power

Hello

Meter iam using is an UNI-T UT181A never had any issue with this one !
Also on connector to the mainboard iam getting weird readings.

3V3 = Jumping all around from 2.9V to 4.5V
12V = Also jumping around from 3.2V to 5.9V then OL.
24V = Jumping around from 19V to 25V

[budm]

Re: 42PFL7406 No Power

Are you getting steady 3.3V at 3.3VSB at pin 1 of connector CN4 per schematic?

[trunks81]

Re: 42PFL7406 No Power

Hello Budm

No that is also jumping around from 2.9 to 4.5V
Measured it multiple times

[budm]

Re: 42PFL7406 No Power

Disconnect the cable between power supply board and the main board to see if the 3.3VSB is steady or not, BTW it is important to use the correct name for the pin.

[trunks81]

Re: 42PFL7406 No Power

When mainboard is disconnected 3.3VSB is steady

[budm]

Re: 42PFL7406 No Power

So it can be weak 3.3VSB power supply or the main board is loading down the power supply too much and causes the 3.3VSB to go into shutdown/restart loop.
You can check the capacitance and ESR of the caps C908, C910 in the hot side of the 3.3VSB section (SCHEMATIC PAGE 1), or just replace them if you do not have EER meter.

[trunks81]

Re: 42PFL7406 No Power

Hello

Tested both caps and the look fine

[thommyX]

Re: 42PFL7406 No Power

Do you have an error code? Blinking LED?

LG Thomas

[thommyX]

Re: 42PFL7406 No Power

IC901 is a DDA010 and IC902 is an ST9S101 / IN1M101.
If the brown out is faulty, you have fluctuating tensions.


LG Thomas

[budm]

Re: 42PFL7406 No Power

Hello

Tested both caps and the look fine

OK, so What dc Voltage do you have on the main filter cap when cable between main board and the power supply board is not connected? about 325VDC?
BTW, what are the rating for those two caps as printed on the body? 10uf an100uf?

[trunks81]

Re: 42PFL7406 No Power

OK, so What dc Voltage do you have on the main filter cap when cable between main board and the power supply board is not connected? about 325VDC?
BTW, what are the rating for those two caps as printed on the body? 10uf an100uf?

When i measure the filtercap and the rectifier they both are 314VDC
This when M/B not connected, Also the caps are 10uf 50v and 100uf 50v

IC901 is a DDA010 and IC902 is an ST9S101 / IN1M101.
If the brown out is faulty, you have fluctuating tensions.

What do you mean by if the brown out is faulty ?

[thommyX]

Re: 42PFL7406 No Power

"IN1M101 provides a precise comparator to detect the rectified AC voltage that can protect the sps when the AC voltage is low." He is a brown out IC. In many cases Delta power supplies break with this IC, both of which I have mentioned.
Always check Q701A and Q701B with this power supply and with Error 3, IC601, R611, R610, R607, R605, D602, R609, C601, Q601 and ZD902.

LG Thomas

[trunks81]

Re: 42PFL7406 No Power

How can i check i IC901 and IC902 are defective ?

[trunks81]

Re: 42PFL7406 No Power

Do you perhaps have the part numbers of Q701A and B ?

[budm]

Re: 42PFL7406 No Power

BTW, what is your TV chassis number?

[trunks81]

Re: 42PFL7406 No Power

Hello number is Q552.2ELA

[budm]

Re: 42PFL7406 No Power

Hello number is Q552.2ELA

OK, I am searching for the schematic that shows the P/N of the IC's, Transistors, etc. for that power supply board.
Can you read the P/N as printed on the IC's, MOSFET's ,and such?

[thommyX]

Re: 42PFL7406 No Power

hope it helps

LG Thomas