phillips 32pfl4507/f7 squeal like a pig

[CraigR]

This philips came in dead and I found on the power board the fuse blown then checked and a mosfet was bad and a diod shorted etc... so I got a repair kit and replaced
F601
Q602
Q601
Q501
Resistor R611
Resistor R501
Diode D608
Diode D607
Diodes D601,D602,D603,D604

After reinstalling the board I plug it in and get a very loud squeal and still no power. If I unplug the cable to the main it goes away. That cable looked good on the contacts. Would I also have a bad main???

[martino]

Re: phillips 32pfl4507/f7 squeal like a pig

No,still a short on the power board,but the mainboard turns on the power supply,hence why it only squeels then.
In short bursts you should measure what voltage is missing when it squeels.Your short will be in the missing voltage section

[CraigR]

Re: phillips 32pfl4507/f7 squeal like a pig

D608 was replaced but reads shorted (in circuit) but ok once removed. I really don't want to plug it in again with all the new parts if something is still shorted.

[R_J]

Re: phillips 32pfl4507/f7 squeal like a pig

check the diodes in the secondary, d650, 651 and the other 2, I can't make out the numbers. It seems like the primary is working and having a short in the secondary would cause the squeal.

[CraigR]

Re: phillips 32pfl4507/f7 squeal like a pig

I did that before posting and none are shorted. D653 and D654 are the other 2.

[kc8adu]

Re: phillips 32pfl4507/f7 squeal like a pig

its likely a shorted mlcc on one of the converters.
looks like there are 3 on that board.common on funai sets.

[CraigR]

Re: phillips 32pfl4507/f7 squeal like a pig

Just to be clear you're talking about what I have circled in this picture. Correct? If so none are shorted.

[R_J]

Re: phillips 32pfl4507/f7 squeal like a pig

are you getting any secondary voltages? Did you try disconnecting the cable going to the led backlights?
There could be a problem with the backlight circuit on the back of the board.
Did you check for shorts accross the secondar voltages, ie: accross c650, You could have a shorted component in the circuit that is supplied by one of the secondary voltages (backlight inverter ic or fet)

[CraigR]

Re: phillips 32pfl4507/f7 squeal like a pig

Unsure on voltage as I unplugged it right away so not to make it worse. I have disconnected all the cables except the main to the power board and still squeals. I also checked the cable to make sure nothing is crossed.

[CraigR]

Re: phillips 32pfl4507/f7 squeal like a pig

UPDATE: it turned out to be on the main board caps C3102, C3103, C3105 working again!

[jackal68]

Re: phillips 32pfl4507/f7 squeal like a pig

UPDATE: it turned out to be on the main board caps C3102, C3103, C3105 working again!

I'm trying to fix the same issue on the same board, my fuse didn't blow but I have a whinning noise coming from the powerboard when the mainboard is connected (no noise when not connected). I suspect the mainboard but not sure what the values of the caps are.

do you know what the values for the 3 capacitors are?

thanks for any help you can provide.

[Maalobs]

Re: phillips 32pfl4507/f7 squeal like a pig

You have the service manual available to download from this page:
https://www.electronica-pt.com/esque...ileinfo/22650/

If you search for those names in the PDF, you'll find that they are all marked as "4.7".
In microFarad I guess, since other capacitors are marked as 0.015, which would mean 15 nanoFarad if the expected unit was microFarad, and that sounds unreasonably low.

[freak]

Re: phillips 32pfl4507/f7 squeal like a pig

UPDATE: it turned out to be on the main board caps C3102, C3103, C3105 working again!

I just had this exact problem and those caps were bad for me as well. Curious how you found which ones were bad. I checked them on board with a cheap dvm with cap mode and they showed OL while the others gave me a value. Popped them off and the TV works. Looks like they are filter caps so I assume that's why it works without them. Gotta order new ones now.