Phillips 42PFL3704D/F7 Dead

[landyboy]

Phillips 42PFL3704D/F7 Totally dead. Check main fuse its good. I have 90vac at the fuse. No DC voltage present. With set on there is 30vac at all 4 pins of the bridge rectifier. It seems everything I test on the hot side has 30vac. Not sure where to start on this one.

[tom66]

Re: Phillips 42PFL3704D/F7 Dead

2nd pic
https://www.badcaps.net/forum/attach...4&d=1376511088

Big orange cap near bridge rectifer, on volt DC range, what do you see?

[budm]

Re: Phillips 42PFL3704D/F7 Dead

Make sure to use the negative leg of that large black filter cap as the Ground ref for the voltage measurement in the primary section, not the chassis. To measure the incoming AC you will use AC meter on the White Neutral wire where the AC power cord is and the Main AC fuse. You are reading 90VAC because you are using the chassis as the ref point.

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

2.7VDC across large orange Cap

[tom66]

Re: Phillips 42PFL3704D/F7 Dead

Is input fuse good?

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

Yes 0.2 ohms

[tom66]

Re: Phillips 42PFL3704D/F7 Dead

Hmm, OK. I'd suggest you remove the bridge rectifier from the circuit and test it out of circuit.

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

Fh1602 tests 480k ohms is that correct?

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

FH1602 is a large plastic fuse? in the main area. Should the be 0 ohms as any other fuse?

[tom66]

Re: Phillips 42PFL3704D/F7 Dead

Where is that device?

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

it does exist, there was a designation on the underside of the board of FH1602 so I thought there was another fuse but it is actually the noise suppression cap. I guess my next move is to desolder bridge rect and test.

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

doesn't exist sorry

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

Bridge Rectifier test ok

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

Underside Pic

[tom66]

Re: Phillips 42PFL3704D/F7 Dead

OK, in the holes of where the bridge rectifier was test voltage between the two middle pins, volts AC.

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

Across the two middle pins set to VAC 0volts

[budm]

Re: Phillips 42PFL3704D/F7 Dead

You are not going to get any AC on the two pins of the bridge until the main board sends the signal to turn on the BLUE power relay. Need to check the STBY power supply section first.
What is the chassis number?

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

I did that test with the PSU isolated

[tom66]

Re: Phillips 42PFL3704D/F7 Dead

AH! I did not notice the relay. It looked like an X-cap. But I did not know why there was an X-cap to ground...
Good catch Bud.

[landyboy]

Re: Phillips 42PFL3704D/F7 Dead

Q1601 1.55m 3.1k 1.82m
Q1602 1.56m 32.1ohms 1.82m