Philips 37PFL5322D/37 Chirping from psu

[dafrizzy]

Re: Philips 37PFL5322D/37 Chirping from psu

Found this same tv in the trash almost a year ago. It worked fine until last month but then began turning off randomly before finally going out tonight for good. This thread has been a huge help. Thanks and hopefully these repairs work!

[Bignew]

Re: Philips 37PFL5322D/37 Chirping from psu

My TV started chirping like a bird yesterday. how difficult is it to replace the diodes? Is soldering involved or is it plug and play?

Thanks

[philliesfan30m]

Re: Philips 37PFL5322D/37 Chirping from psu

soldering is involved.

[Bignew]

Re: Philips 37PFL5322D/37 Chirping from psu

soldering is involved.

Oh boy, thanks

[lizzrd]

Re: Philips 37PFL5322D/37 Chirping from psu

I also have this Philips LCD, really liked it until yesterday. After finding this site and this thread, i am thinking of replacing these caps with the Panasonic FM series.
I do have a question about the 2-3 diodes mentioned on the first page next to the transformer. There is a link to one of them, but i am not sure yet if they are all the same ?
Thanks for anymore info or instructions...

[lizzrd]

Re: Philips 37PFL5322D/37 Chirping from psu

Rereading the thread and checking the pic, one is different. Mr.Bill said he replaced diodes, 2, next to the transformer, location zd902 and zd904.
budm has a link to the 'one' Bill replaced, a snubber circuit? So this is where i am confused. I would like to do all three if i could get another diode part #. Would that be the thing to do ? , again thanks in advance.

[lizzrd]

Re: Philips 37PFL5322D/37 Chirping from psu

I have my board out and ready to order some parts. I guess i am still looking for clarification on the 3 diodes... zd902 + zd904 next to the transformer are P6ke zeners.
I cannot read or find info for the one at position D925 ? is this a zener diode also ?

[ktgohdt125]

Re: Philips 37PFL5322D/37 Chirping from psu

I have my board out and ready to order some parts. I guess i am still looking for clarification on the 3 diodes... zd902 + zd904 next to the transformer are P6ke zeners.
I cannot read or find info for the one at position D925 ? is this a zener diode also ?

D925=UF1007 (UF1007. 1.0A ULTRA-FAST RECTIFIER)

here i attach a 37" to 47" PFL series of service manual look from pg 57 to 63

hopes this help those who need it.

regards
ktgoh

[lizzrd]

Re: Philips 37PFL5322D/37 Chirping from psu

I can not say " i can read an electrical circuits' drawings" , but thanks for your reply.
I google that uf1007 and found nothing like it at Dig-it-Key... ?

[stj]

Re: Philips 37PFL5322D/37 Chirping from psu

uf4007

[lizzrd]

Re: Philips 37PFL5322D/37 Chirping from psu

Thanks for your replies and help...

[budm]

Re: Philips 37PFL5322D/37 Chirping from psu

Digikey, UF1007:
http://www.digikey.com/product-detai...DITR-ND/248654
Mouser:
http://www.mouser.com/ProductDetail/...XLfVE5J3hj8Q==
Spec:


UF4007 will work

[lizzrd]

Re: Philips 37PFL5322D/37 Chirping from psu

well, a bit disappointed, had a guy at the PC repair shop solder in the two P6KE diodes next to the transformer (ZD902 + ZD904) and the other
UF1007 in the D925 spot.
He also replaced the 3 large caps. with newer FM series. He did not replace the large cap that is by itself. It did not look bad like the others, but he said it was different ? I guess i thought all the caps circled were the same and ordered 4. His work looked good.
So, the tv came on, no chirp, no picture , but it had sound.
Any thoughts on my next move ? I almost bought an iron to do this but did not want to screw up my board. I do have a Sunpro multi-meter...

[lizzrd]

Re: Philips 37PFL5322D/37 Chirping from psu

what if i replaced the pin plug?, the one with all the little wires,
onto the wrong set or bank of pins ?
i am talking about the two rows next to the 'Badcaps' in the first pic...

[orgwood]

Re: Philips 37PFL5322D/37 Chirping from psu

I need your help. I grew up learning linear PS design but never switchers. I know about PWM so I assume it has something to do with that. Here's where I am with this particular problem...
I replaced all caps and the 3 diodes with a kit I bought from a reputable seller. Still ticks but doesn't sound like a chirp to me. Replaced the 2 diodes in the 12VDC rail...BTW I found a schematic online for this PS so I'm able to deal with section testing. I'm uploading it...mine's the 37". These seem to be used on Magnavox sets too, maybe others.
I measured the 2 rails and only the 12VDC is working. I put my Oscope on both sections -luckily they are very similar in design and I have almost a sine wave across both zener sections going into the FETs. I pulled the output diodes from the output transformer for the 24VDC section and tested them with the MMeter diode range and the look good. So I went back to the main DC rail that feeds both sections and of course its working since the 12VDC section works. Then I pulled some of the middle diodes for testing and they seem okay. I'm pretty certain the ticking noise is coming from the 24VDC output transformer T905 but I can't believe it's bad since I think they are pretty durable. Do bad output caps cause it to short? ANY way to test it with an ohmmeter or Oscope in circuit.

[budm]

Re: Philips 37PFL5322D/37 Chirping from psu

12V is an always on power supply, the 24V is the switched supply that has to be turned on by the command signal at the STANDBY pin, it needs about 3VDC and secondary side GND at that pin. to turn on. This signal is also used to turn on the PFC Voltage booster which will boost the DC Voltage on the main filter cap form 165VDC to >360VDC.
You should disconnect the load to the 24VDC output for now.

[orgwood]

Re: Philips 37PFL5322D/37 Chirping from psu

Thanks budm, I will give that a go tomorrow to see if the 24VDC comes alive with a standby signal. Would that main filter cap be C907 270uF 450V? I'll check it tomorrow. But is that ticking normal when the 12 & 24VDC are disconnected?

[budm]

Re: Philips 37PFL5322D/37 Chirping from psu

"But is that ticking normal when the 12 & 24VDC are disconnected?" Ticking is not normal.
So were you testing the power supply board with the main board connected to the power supply?
If you do, then the STANDBY may be present, you should check the Voltage at the STANDBY pin to see if it goes from <1 V to > 2.5VDC when power switch is activated. If it does then check the Voltage on the main cap since the 24VDC needs that booted Voltage to function.
If you disconnect the load on the 24V line and it stops clicking, then it can be that too much load is on the 24V due to problem in the inverter boards so the 24V goes into start up/shutdown cycle.

[orgwood]

Re: Philips 37PFL5322D/37 Chirping from psu

All I've got is the PS board here so no main board is connected....the set is at my son's about 20 minutes away. I don't even have the power switch here so I'm just going to provide the 3VDC through a resistor. I see it activates the base of an NPN with a 4.7K in series so I'll just take it to the 12VDC. Thanks again for the VERY fast replies...it's exactly what I needed to get me going forward with this.

[orgwood]

Re: Philips 37PFL5322D/37 Chirping from psu

"But is that ticking normal when the 12 & 24VDC are disconnected?" Ticking is not normal.
So were you testing the power supply board with the main board connected to the power supply?
If you do, then the STANDBY may be present, you should check the Voltage at the STANDBY pin to see if it goes from <1 V to > 2.5VDC when power switch is activated. If it does then check the Voltage on the main cap since the 24VDC needs that booted Voltage to function.
If you disconnect the load on the 24V line and it stops clicking, then it can be that too much load is on the 24V due to problem in the inverter boards so the 24V goes into start up/shutdown cycle.

Well, I've got bad news and some news not so great. The bad news is that my Oscope wasn't free floating so I blew out the AC line circuits trying to read the HOT side waveforms. I believe I can fix those bad traces though and I had a spare BD installed when it happened so I think I can put the original one back in. Before that happened, I was able to watch the 24VDC rail rise to around 10VDC when I biased the standby pin ON using a 4.7K resistor to the 12VDC rail. It seemed like it ticked a lot faster while this was happening. I will try to fix the traces tomorrow and have another go at it. Since these boards are scarce, I wondering about putting in a 12VDC PS constantly on and adding a 24VDC separate one and do a manual turn on. Once on, the remote should do everything but control power. Do you happen to know the specs on the amps for both rails? I've got some LCD switchers I think could work but they may not have enough output capability. If I can get the 12VDC rail working, I might just try to put in an extra 24VDC PS just to get this set running for my son. Any thoughts? Thanks, Dave