42PFL7406 No Power

[trunks81]

Re: 42PFL7406 No Power

Hello

this are the part numbers of those parts

Q601 = K3530
Q801 = Cannot read
Q701A = K4A60DA
Q701B = K4A60DA
IC601 = 2QS02G
IC801 = 1608B
IC701 = DDA009
IC901 = DDA010
IC902 = S101202D

[trunks81]

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

Changed both IC and problem is still the same

[dick_barton]

Re: 42PFL7406 No Power

What voltage do you have across C908 and also at the FB pin 2 of IC901 and are they steady

[trunks81]

Re: 42PFL7406 No Power

On pin 2 of IC902 iam getting 0V to 0.23V
On C908 iam getting 13v to 19v
Also i found that ZD904 is low in diodemode 0.0029 in both directions
When soldered out iam getting 0.69 and reverse 2,7

[dick_barton]

Re: 42PFL7406 No Power

It looks like your pfc circuit is switching on when the voltage across C908 reaches 18V and then stopping when the voltage falls which would be the reason your secondary voltages are oscillating.

It does look like a short but is it the zener or R902 since that is across ZD904. You could lift one end of ZD904 to test it or it could be a short on the IC pin to ground.

CS is the current source pin which would have a low value resistor (R902) attached to it and hot ground.

[trunks81]

Re: 42PFL7406 No Power

When ZD904 soldered out iam getting 3ohm in R902 also when soldered out it is 3ohm marking on the resistor is 47Y

[dick_barton]

Re: 42PFL7406 No Power

47Y is 47 ohms according to http://kiloohm.info/eia96-resistor/47Y

Are you certain it's 47Y since that seems to be a high value resistor as a source resistor.

[trunks81]

Re: 42PFL7406 No Power

iam confused.. according to the same site it is an 3.01 ohm
Please see picture in previous post for resistor

[dick_barton]

Re: 42PFL7406 No Power

I stand corrected it is 3.01 ohms.

[budm]

Re: 42PFL7406 No Power

I forgot about this thread, too busy with the 37" & 47" threads.
So at this point if you run the power supply board by itself and force it on, is the PFC boost Voltage staying on?

[trunks81]

Re: 42PFL7406 No Power

I connected pin 1 and 2 on 1M95 (CN4) with an 1K Resistor
And on

C800 = 313VDC
C908 = 17.21VDC

[budm]

Re: 42PFL7406 No Power

I connected pin 1 and 2 on 1M95 (CN4) with an 1K Resistor
And on

C800 = 313VDC
C908 = 17.21VDC

The PS-ON (STANDBY) for this Philips power supply is Active Low, so you need to Ground pin 2 (STANDBY) of CN4 to Ground pin 3, 4, 8, or 14 using 100 Ohms resistor or so to turn on the power supply.

[trunks81]

Re: 42PFL7406 No Power

does it really need to be an 100ohm ? because i dont have it right now

When stubborn using an 1K iam getting

C800=407
C908=17.30

[dick_barton]

Re: 42PFL7406 No Power

What are the values of R959 & R960.

For standby: - do you have a couple of resistors you could put in parallel. e.g. 2 x 1K in parallel = 500 ohms

[trunks81]

Re: 42PFL7406 No Power

Both resistor measure oke, measured them in circuit

R959 = 01D = 100kohm
R960 = 69B = 5.11kohm

[dick_barton]

Re: 42PFL7406 No Power

Looking at those values I think it's safe enough to short standby to ground.

[budm]

Re: 42PFL7406 No Power

I suggest using resistor just in case OP ground the wrong pin on the connector by mistake if he jumps directly, OP can jump STANDBY pin to ground directly with no problem, I am just afraid that OP will make mistake and ground the wrong pin.

[trunks81]

Re: 42PFL7406 No Power

ive used an 1K instead of 100ohm.. and that seems to work also

[budm]

Re: 42PFL7406 No Power

So is the PFC Boosted Voltage present then?

[trunks81]

Re: 42PFL7406 No Power

does it really need to be an 100ohm ? because i dont have it right now

When stubborn using an 1K iam getting

C800=407VDC
C908=17.30VDC

This is what iam getting with 1K present