Philips 32PFL5322D/37 power supply repair

[budm]

Re: Philips 32PFL5322D/37 power supply repair

From what I can see, this power supply has PFC circuits, and from what it sounds, the primary DC voltage did not switch to higher level when the it is on, if you measure the DC voltage on that large cap 120uf 450v when it is plugged but not being told to tun on, the voltage on that cap should be around 170vdc, when the TV is commanded to turn on ,the voltage is kicked up to about 400vdc. There should be an IC for the PFC controller on the bottom of the board. Notes: next to the large cap above it is a large inductor for the PFC.

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair

The large cap has 163V when the power supply is in standby mode, and 161V when I turn it on with a resistor. Sounds like the PFC is not turning on. Could this be causing the low output voltage?

In other news, I traced R526, it is connected to the optocoupler that is connected to U651 regulator on the secondary side. Paging Mr Bill back to the thread, if he can measure the resistor on his supply and let me know the value it may help diagnose.

[Th3_uN1Qu3]

Re: Philips 32PFL5322D/37 power supply repair

The large cap has 163V when the power supply is in standby mode, and 161V when I turn it on with a resistor. Sounds like the PFC is not turning on. Could this be causing the low output voltage?

Yes, definitely.

[budm]

Re: Philips 32PFL5322D/37 power supply repair

See example of the PFC controlled SMPS diagram.

[tom66]

Re: Philips 32PFL5322D/37 power supply repair

You probably have a shorted diode on the output of the PFC circuit, or a failed PFC controller. I think a shorted diode would cause a fuse to blow; but I'm not sure.

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair

Tom66, no shorted diodes that I can find, there are 3 that come directly off the inductor that budm referred to as the PFC inductor, D065, D064, and D080. All 3 read 550 mV in one direction and open circuit in the other.

The PFC controller is an L6562D. There is an apparent short between GND and ZCD, which reads 14 ohms in each direction. Looks like another shorted chip, I'll pull it tonight and test out of circuit.

[budm]

Re: Philips 32PFL5322D/37 power supply repair

Here is the Datashett for the L6562D, more likely the Chinese will just copy the application notes on how to hook it up, it should be closed to what you ave in your P.S.

https://cdn.badcaps-static.com/pdfs/...3407e8de8a.pdf

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair

Pulled the PFC controller and sure enough, still reads 14 ohms. At least they are cheap, $1.51 on digikey. And it will be here in 2 days, woop woop. I'll report back after I get it installed.

[budm]

Re: Philips 32PFL5322D/37 power supply repair

Chek the MOSFET that is driven by this IC and related parts around this IC before installing the new IC.

[Mr Bill]

Re: Philips 32PFL5322D/37 power supply repair

Looking on the primary side, I don't see anything immediately obvious. The only thing I can see is resistor R526. According to the color code, it should be 1.6k ohm, but on my meter reads 0.99k ohm. This may be nothing as there were other resistors that did not follow the standard color code.

Any other places to look?

I'm getting .996k ohm for R526 on my supply

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair

budm: I checked the MOSFET that is mounted right next to the IC, and it tests good. Also checked the surface mount diodes and they all appear to be working properly.

Mr Bill: Thanks for the update! Guess it was another wonderful non standard coding.

The IC is on order, should be here Thursday as I hit the digikey cutoff time and I already have the shipped notification.

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair



IT WORKS!!!!

Installed the new PFC controller, and it fired right up! Thanks so much for all the help you guys, I couldn't have done it without your help!

I'd especially like to thank, in no particular order:

PlainBill
retiredcaps
tom66
Th3_uN1Qu3
Mr Bill
budm

You guys are awesome!

[budm]

Re: Philips 32PFL5322D/37 power supply repair

Thanks for the feedback, I am sure it will help out other people in the future as well.

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair

It doesn't work!

Well to be more precise, it worked for about 10 minutes. I saw a bright spark, then the fuse blew. Gah! I'll post back after I get the supply out and look at it.

[budm]

Re: Philips 32PFL5322D/37 power supply repair

Check the DC voltage on that large cap again when you figure out what blew up, it may have gone too high or you may have had bad MOSFET that may check OK iwht the Ohm meter but will break down when it actually seeing 400vdc. I use curve tracer to truly test the break down voltage of the high voltage devices.

[Agent24]

Re: Philips 32PFL5322D/37 power supply repair

Judging by the position in the circuit, it's definitely 1 ohm. Not sure what the last violet band is doing there, but brown black gold gold is 1 ohm 5%.

If the violet band is tolerance, it means +/-0.1% and if it's referring to temperature coefficient it's 5 ppm/Kelvin

I'd say temperature because the 2nd gold band is likely the tolerance.

(http://en.wikipedia.org/wiki/Electro...de#Color_bands)

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair

After looking over the board, it looks like everything is intact. Aside from a nice scorch mark under the bridge rectifier, everything looks good. No shorted mosfets, no blown diodes, etc.

Under the bridge rectifier is another story. It isn't shorted out, but between one of the AC legs and the + leg there was a nice burn. I think it arced between those two and that's what tripped off the fuse.

Now a few pages back I mentioned how I was getting some burning that was between those same two leads. Before I just cleaned it up real good with some rubbing alcohol as there was a nice layer of flux. I'd like to clean up the rectifier connections so this can't happen again. Unfortunately the last owner really made a mess of these connections. It looks the pads are starting to lift. Attached is a picture of how they look now, if you think of the connections from 1-4 from the left to the right, the spark was between 3 and 4.

I think connection 4 looks good, the others need some work. Any tips on how to fix them? 1 and 2 are the pads that were lifting off.

Edit: when cleaning the connections with rubbing alcohol I noticed it arced bad enough to pit the circuit board a little. Nice.

[budm]

Re: Philips 32PFL5322D/37 power supply repair

What I do is to remove the solder, then scrape off the green coating on the PCB to expose the copper layer, the n wrap small piece of wire arounf the pin and solder the wire on the leg and the other end of the wire will be soldered to the exposed copper. It sounds like it did not have good connection on the old joints. Make sure to clean off any solder residues, carbon marks, etc. real well, also make sure there is no solder splatter from the previous works. Ohm thing out when you are done.

[rpgruss]

Re: Philips 32PFL5322D/37 power supply repair

This has to be a bad joke or something...

Got the bridge connections all cleaned up, put it back in the TV. It ran a bit longer this time, about 20 minutes or so, long enough for me to program a universal remote and set up the channel list. Then it turns off, starts blinking good old 8 blink error code.



Take the power supply out, reconnect my turn-on resistor, and check the outputs. There is 25.5V on the 24v rail, but the other outputs they are at 0V. Now I know from my previous experience the 24v rail discharges very slowly, after 5 minutes of power off it was at 23.3v.

However, if I let the power supply sit for a couple of minutes, then turn it back on, the voltages appear, if only for a brief amount of time.

There are no shorts in the PFC chip. When mains power is applied with the turn on resistor in place there is a steady 406V across the main capacitor.

What gives?

[budm]

Re: Philips 32PFL5322D/37 power supply repair

The PFC Voltage Booster circuits is for the 24vdc. Are you still getting the 5v stby? Your PFC is working otherwise will not get that 400vdc.