Philips 23PFL5522D/12 PSU problems

[sparkydz]

Hi there,

My Philips TV (23PFL5522D/12, chassis LC7.2E LB) has just packed in again. PSU makes a ticking noise even standalone outside ot the TV. It's my own fault - although I ordered a full set of caps (or almost), I decided that the less soldering I did, the less chance there was of messing things up. BAD DECISION! OK, this time I've changed the rest in the bad-boys corner, but noticed that one of the SMD zeners was fried. I've desoldered it, but don't know what it's value was. I checked the SM I got from Elektrotanya for this chassis, but the PSU doesn't match. Photos of my kit below. My questions:

1. What is the value of zener ZD203? and can I use a radial one for easier soldering?

2. The original caps were CapXon GF and GL series which I replaced with Panasonic FM/FK series. Is this OK?

3. I've only replaced the caps on the far right of the photo (surrounded by a heat sink. I guess I should change the others too (excepting the large Rubycon), but one of them was siliconed to the board and its value unreadable. It's at the top, more or less in the middle in the photo (and looking a bit of a mess where I've tried to scrape away the silicone), is a 50V and labelled C23 on the board. Anyone know what its value is? I could desolder it and measure the capacitance, but that would assume it's OK.

Thanks for any help you can give me!

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

Hello again,

I've still not got managed to sort things out, but have a couple of ideas:

- Not sure about my FK series Panasonic caps. Are these ESR, or should I replace them with FM or FR series?

- The zener has a wide red band, a narrow red band and a narrow green band. Looking it up on the web suggests 15V, but it's on the end of the 5v supply circuit. What appears to be an identical circuit next to it gives 5.80 -5.92V when powered up ... so it must be ~5.8V zener, right?

Can anyone help me out?

Mike

[budm]

Re: Philips 23PFL5522D/12 PSU problems

Is the band (Catohde) side connected to the +5V power supply out put and the Anode side is connected to ground? If it is, it is just a safety clamping Zener Diode in case the +5V loses its regulation, the Zener will scarifies itself and shorted out, the Zener voltage is usually 6.2V 1/2W.

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

Thanks for your quick reply!
Yep, that's it, but there's something odd with the measured voltages.

- The dead zener was between "Gnd-audio" and "-Vaudio", but I get a constant 0V across it.

- The other (still ok?) zener is between "Gnd-audio" and "+Vaudio", and here the voltage switches between 0V and about 5.8V with every ticking noise. What might be causing this? Could it be the FK series caps aren't low ESR? Or something's toast further upstream?

-- Mike

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

A bit more info - I think audio voltages should probably be + and - 12V, so I don't know why I'm only getting 5.8V.

[budm]

Re: Philips 23PFL5522D/12 PSU problems

for 23" TV I will doubt very much that they will use bi-polar (+/-) power supply for the audio (typical op-amp uses +/- PS).
You may have to try to locate the service manual for this TV.

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

Hmmm, got the service manual from ElektroTanya, but the 2 versions of PSU are _nothing_ like mine, so it's pretty unusable. I tried Philips and Delta, but both were (as expected) unhelpful. I'll see if I can guess what the PSU gives by looking at what the other boards use...

[mr2013e]

Re: Philips 23PFL5522D/12 PSU problems

i think zd203 and zd202 same diode.

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

Just noticed a bit of text half hidden by a heatsink - see blurry photo. Looks like the audio is bipolar and 12V after all, so the zeners are 15V. I guess the 'good' one just isn't getting enough time to get up to 12V before the 'bzzzzzz-tick' shutdown.

When I recapped, most of my new caps were Panasonic FM, but some were FK. My guess is that the FKs are not low enough ESR. Will change for FM or FR and post my results. Fingers crossed...

-- Mike

[budm]

Re: Philips 23PFL5522D/12 PSU problems

Wow, this is the first time I see TV power supply with +/- 12VDC outputs.

[mr2013e]

Re: Philips 23PFL5522D/12 PSU problems

so you can measure +-12volts on zd202 and zd203.???

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

Can't measure much yet : zd203 is dead and has been removed, and as I said earlier I only get up to about 5.9V on zd202 before the PSU shuts off and retries. I'll retest and report on my findings when recapped and (hopefully) working.

-- Mike

[mr2013e]

Re: Philips 23PFL5522D/12 PSU problems

are you sure this output of power supply is for sound.(zd202 zd203)

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

Yep, it supplies the -Vaudio and +Vaudio pins (I think I said this before).

-- Mike

[mr2013e]

Re: Philips 23PFL5522D/12 PSU problems

then remove -+12v socket in power board and measure volts on zd202 and zd203

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

That's what I've been doing - the PSU is completely disconnected from the rest of the TV. Only the 230V supply is connected.

-- Mike

[mr2013e]

Re: Philips 23PFL5522D/12 PSU problems

then recap with PANASONIC .and use 12volt zener for zd203.

[sparkydz]

Re: Philips 23PFL5522D/12 PSU problems

Can anyone tell me if the Panasonic FK caps are likely to be causing me problems (related to ESR)? I can try replacing them again with FM or FR series, but it would be nice to know if it's worth trying. And for the smaller caps that don't exist in FM/FR (eg 1uF) what should I use? FC?

[budm]

Re: Philips 23PFL5522D/12 PSU problems

FK should be fine.1uf does not have to be low ESR, but should be 105C rating.

[mr2013e]

Re: Philips 23PFL5522D/12 PSU problems

panasonic caps have so much life time under stress.good quality indeed