Philips 32PFL3504D/F7 black screen

[Gorrillasnot]

I'll start off by saying I'm a total newb when it comes to TVs and my tools are limited. I have a 40w soldering iron and a cheap centech digital multimeter (harbour freight special)

According to the owner that was about to throw away the TV before I asked if I could have it the TV got fried during a thunderstorm last summer.

When plugged in there is a white led that lights up on the bottom left corner but nothing happens when pressing the power button.

I don't have pics of the boards yet but there are some in another thread here https://www.badcaps.net/forum/showthread.php?t=12126

I'm probably in way over my head but where would be a good place to start testing?

thanks

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

Here are some pics of the boards.
Where do I check to see if the power supply is working?
Most guides I've read show a big plug with several wires with labels on the board such as 12v, 3.3v etc. but I don't see such a plug on my board.
Also how do I check voltage at the big cap on the power board?

thanks

[selldoor]

Re: Philips 32PFL3504D/F7 black screen

Pictures are not quite good enough for trouble shooting -
An overall picture showing how all the boards are connected would have helped.
In pic 5 is the Black and white cable the mains in and does the Black and red feed to the
inverter board - pic2.
Have you tested that first glass fuse

You dont have the connector because unusually the power supply seems to be on the same board as the main board

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

Sorry for the bad pictures. My camera is a crappy point and shoot.

Yep the black and white is a/c and the red and black goes to the inverter board.
Is that (the red and black wire) where to test the volts for the big cap?
edit: With the tv plugged in I checked the voltage at the red and black wire and it is 163.5v.

Yep the glass fuse is good and I am getting a white led light that comes on (standby?)

I see various jumper wires on the board..since there is no connector are there certain jumper wire locations that could be checked?

thanks

[selldoor]

Re: Philips 32PFL3504D/F7 black screen

Well if you look at the back of the board and the red and black connect to the
big cap then yes you can just measure there.
I was going to suggest you did that anyway.
HIGH VOLTAGE so take care and dont touch any part of the board with your hand.
it is faulty so who knows what is at what voltage.
Set you meter on volts DC 600 and probe red to red and black to black.

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

I get 163.5v at the red and black wire. I get 167.4v at the large cap as measured from that backside of the board.

[selldoor]

Re: Philips 32PFL3504D/F7 black screen

That is near enough- I cant do more than suggest you do the tests mentioned in the other
post you flagged up - his pics are no better than yours so I cant see where to point you.
Download and follow the test points on the service manual. Bear in mind that the inverter
board may be the problem.

There are usually fuses on the inverter board but I cant see it clear enough - there also appears to be a hot (brown spot) but can tell really and we dont know what is on the other side.

Good light (withoutflash) is what is needed for good pics - just looked at your weather has a full sun on the pic but says mainly cloudy and getting worse next few days.

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

here are some more pics of the inverter board. I hope they are ok?

Since I am getting around 167v from the big cap and out of the black and red wire does that mean the PSU board is probably ok?

[selldoor]

Re: Philips 32PFL3504D/F7 black screen

Since I am getting around 167v from the big cap and out of the black and red wire does that mean the PSU board is probably ok?

Not really - you would still need to establish the secondary voltages are ok.
3v 5v and 12v probably as you say having a led lit suggests at least the 3 or 5 is ok.
I am guessing it tells you in the service manual where to test for them.

[newtothis]

Re: Philips 32PFL3504D/F7 black screen

can you take a pic of the entire back of the chassis so we know what is going where.

thanks

[selldoor]

Re: Philips 32PFL3504D/F7 black screen

When you said thunderstorm I was thinking lightning strike/ power surge but wonder if it is water damaged?

[budm]

Re: Philips 32PFL3504D/F7 black screen

Diagrams: Not sure if it is the same chassis (chassis FL9.1) as yours or not.

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

selldoor: The previous owner said there was a lightning strike then the screen went blank and she heard a sizzling noise.
Also the TV came from a pretty bad environment. The previous owner is a chain smoker and has a bunch of cats. To make things worse it had been stored in a damp unheated building for the past year or so. (note the rust on tuner).
The TV is probably not worth fixing but it was the only free one I could get to practice on so I figured why not give it a try.

newtothis: Attached is a pic of the back of the chassis.

budm: Yep my chassis is FL9.1. thanks for the diagrams.

everyone: Is there an order to the voltages I should check. I mean after testing the volts at the main cap which was around 167v what voltage should I check next?

thanks

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

I found a diode at location D637 (circled in the pic) on the power board that I think is bad.
I set my multimeter to diode mode and it gave a reading of 037 then I reversed the test leads and again it measured 037. That would indicate the diode is bad since I got a reading both ways right?

I looked the diode up in the manual and it says it is a Schottky Barrier Diode SB160 part# NDWZ000SB160.

Is it likely that 1 diode is the whole problem?
where would be a good place to purchase 1? I see on ebay the cheapest is 12.99 + s/h for qty 25 (us dealer) Would radio shack carry them?

thanks

[selldoor]

Re: Philips 32PFL3504D/F7 black screen

selldoor: The previous owner said there was a lightning strike then the screen went blank and she heard a sizzling noise.

perhaps the cat got struck by lightning that would sizzle

You will need to remove the diode and test off board.

Did you not find this? in the other post or is your board different
"On page 41 of the service manual, there is a very nice schematic with voltage test points. "

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

Removed the diode and got a reading (think 180 something) 1 way and a 1 the other way. Looks like the diode is good. I guess its back to the drawing board.

I will check out page 41 of the manual.

I have possibly a stupid question. The test points would be on the bottom side of the board right? Would it be fairly safe to unhook everything from the power board, flip it upside down on a wooden table, plug the AC cord in, and run through the test points?
And lastly does the inverter board need to be connected to the mainboard when testing?

thanks

[selldoor]

Re: Philips 32PFL3504D/F7 black screen

No not a stupid question - the stupid ones do what you suggest on a metal bench


Sometimes it is better of you can have it all connected as some voltages are unregulated and run out of true if a load is missing.
On a system with separate main and power they have to be connected to test secondary voltages as the power supply wont start without the main.

Some systems recognise a disconnection as a fault and close down.

At this point you are probably ok without the inverter if its difficult- depending on the results you can always do it again with it. You might have to do that anyway if the inverter board is pulling the system down.

Many of us use sheets of card between the various boards to keep them connected but apart if you see what I mean.

Another thing to watch is that sometimes extra ground connections between
boards are required. We have had good repairs that didint actually work until
the boards were firmly screwed back onto the frame.

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

thanks for all the help guys.
I never did get the TV fixed.
I ended up getting a different (cleaner) TV to practice on. One that wasn't struck by lightning, cat hair and nicotine incrusted, or stored in a damp room.

anyways thanks again guys

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

Out of boredom and with nothing to do I am back to tinkering with this TV.

I never could find the problem with the original power board so I bought a PSU/main board off of ebay.
Once I received the board I noticed it looked different then my original board. It has 2 extra connectors (see pictures).

I got to looking and the board number I used for my ebay search BA94F0F0102 4_A was the same, but the numbers on the white stickers were different. Original board says A91F2-MPW and ebay board is A94F1-MPW.

Needless to say I tried the new board and my TV still doesn't work. Are these boards interchangeable?

thanks

[Gorrillasnot]

Re: Philips 32PFL3504D/F7 black screen

bump