Philips 42PF7320 plasma, strange problems

[tom66]

Re: Philips 42PF7320 plasma, strange problems

The voltages look fine -- I don't think the problem is with the PSU.

[DPark]

Re: Philips 42PF7320 plasma, strange problems

Finally had some time to mess with this TV again. Model: 42PF222A/37 Power Supply: 44-00101B.
It will power on for about 5-10 minutes, but then shuts off after a couple of relay clicks. 5-blink error code when this happens.
All voltages seem to check out fine with the new meter I have when the power is on. The only one that seems to be more than 10% off is SND_P.

Factory Specs / Actual Reading
Va=70 / 70
Vsc=206 / 206
Se=86 / 86
Vset=195 / 194.2
5v2=5.2 / 5.17
5vsw=5.2 /5.15
8v6=8.6 / 8.64
12v=12.5 / 12
SND_P=18v / 20.2

Anyone have any suggestions on what else I should check or replace? I could just buy a refurb board for less than $50 but what fun would that be?

[retiredcaps]

Re: Philips 42PF7320 plasma, strange problems

On some panels Vset is measured as Vs+Vset so subtract Vs from it to get actual Vset.

@DPark, what is your Vs+ reading?

If your multimeter is working correctly, then we need to know the Vs+ reading.

[retiredcaps]

Re: Philips 42PF7320 plasma, strange problems

I tested the multimeter at the 5v location retiredbadcaps sugggested. All seems normal.

Multimeter at 600 - 4-5 (fluctuates) on the display
Multimeter at 200 - 5.1 on the display
Multimeter at 20 - 5.13 on the display

My interpretation of your readings above is that your multimeter is defective when using the 600V range.

At 600, it should show steady/solid 5 because your standby voltage is a steady/solid 5.13.

When it is fluctuating between 4-5, the "4" reading suggests it can be between 3.51 and 4.49.

I suggest borrowing or using another multimeter to redo the vset reading.

Here is a link to your multimeter



As you can see on page 8, when it is set to 600V DC range, there is only one digit of resolution so it should show a steady/solid 5V.

[DPark]

Re: Philips 42PF7320 plasma, strange problems

I tried the black probe (with red on the vset pin) to the pin connector ground as well as on the board at different points and it seems to range between 480-530V. Even the two ground pins in the same connector seemed to measure different amounts!

I tested the multimeter at the 5v location retiredbadcaps sugggested. All seems normal.

Multimeter at 600 - 4-5 (fluctuates) on the display
Multimeter at 200 - 5.1 on the display
Multimeter at 20 - 5.13 on the display

[retiredcaps]

Re: Philips 42PF7320 plasma, strange problems

3) Measure the 5V standby rail with it set on 200V DC. It should read something like 5V.

Whoops, just noticed my error in cut & paste above.

The "correct" #3 is

3) Measure the 5V standby rail with it set on 600V DC. It should read something like 5.0V.

[retiredcaps]

Re: Philips 42PF7320 plasma, strange problems

To make sure your multimeter is working properly, try the following test.

1) Measure the 5V standby rail with it set on 20V DC. It should read something like 5.00V.

2) Measure the 5V standby rail with it set on 200V DC. It should read something like 5.0V.

3) Measure the 5V standby rail with it set on 200V DC. It should read something like 5V.

4) Report your findings for all above.

If your multimeter is not working correct, which is possible, borrow/buy another one. In addition, if you want help fixing the one you have, start a new post and I'll make suggestions on what could be wrong.

PS. One retiredcaps' bonus point for a picture of your multimeter.

[retiredcaps]

Re: Philips 42PF7320 plasma, strange problems

Still have about the same results.

Try putting your black probe on the connector pin marked GND (just below Vset).

[DPark]

Re: Philips 42PF7320 plasma, strange problems

Ok, I briefly had a chance to get back to it tonight. I changed out the battery to the multimeter. Still have about the same results.

[DPark]

Re: Philips 42PF7320 plasma, strange problems

Thanks for the info. I haven't been able to get back to the TV project for a little while, but I will try the suggestions and I'll keep you updated.

[tom66]

Re: Philips 42PF7320 plasma, strange problems

And, your meter may be set to VAC?
On some panels Vset is measured as Vs+Vset so subtract Vs from it to get actual Vset.

[retiredcaps]

Re: Philips 42PF7320 plasma, strange problems

Show us a picture of your multimeter.

Some multimeters have low batteries and give incorrect readings, but there is no indication of the low battery indicator on the lcd screen.

[DPark]

Re: Philips 42PF7320 plasma, strange problems

I don't think I'm measuring it wrong. I have the black probe touching the chassis and the red wire going to the little solder spot where it says "vset." Then, I turn on the power. What could I be doing wrong?

[tom66]

Re: Philips 42PF7320 plasma, strange problems

Vset should be very close to Vs (180~210V), not guaranteed to be exact, but very close.
A 560V Vset would burn your Y-main and buffers, so you're probably measuring it wrong...

[retiredcaps]

Re: Philips 42PF7320 plasma, strange problems

After checking some voltages and matching them up with the sticker on the upper right of the chassis, everything seems normal except the Vset reading was 560v instead of the 195v it should be at!?

Tom66 is the plasma expert, but I can't ever recall seeing a post where voltage is 560V DC. If that reading is correct, then I would have expected many capacitors to go .

[DPark]

Re: Philips 42PF7320 plasma, strange problems

I forgot to mention that the power supply is the one in this thread. (LJ44-00101B) The TV is a similar model (42 PF 7220A/37B).

[DPark]

Re: Philips 42PF7320 plasma, strange problems

Hi there. First off, I've learned a lot from reading these forums and I wanted to to thank all the people who contribute to this site. I'm pretty new to TV repair and have had some luck in finding simple capacitor swap out jobs.

Now, here's my problem. I have a Philips 42" with a 5 blink red led code. The TV will power on for about 10 minutes (time varies) and then there will be a crackle and it will shut off with a 5 blink led. If you unplug it and give it some time, it can be reproduced, but not always.
I have visually inspected all the caps on the board (ESR meter on the way since I seem to be getting more involved in repair) and have found none to be bulging or domed.
After checking some voltages and matching them up with the sticker on the upper right of the chassis, everything seems normal except the Vset reading was 560v instead of the 195v it should be at! Hmm... I have a feeling that this has something to do with the problem.
What could be causing this? What is my next course of action in troubleshooting this board at a component level?

[homerging]

Re: Philips 42PF7320 plasma, strange problems

There are number of larger 16mm diam. Samxon KMOD caps that may need replacing (680uf 100v, 47uf 350v, 100uf 160v). What I am not clear on is are there special requirements for "filter" caps or live vs cold (dc?) if these are those? Or are the likes of Rubycon ZLJ or Panasonic EE likely to be fine so long as they match ESR and ripple current specs?

[homerging]

Re: Philips 42PF7320 plasma, strange problems

Should be fine. Samwha WB are crap caps and never last (possibly they lied on the spec sheet - who knows?), the power supply should work fine with the Rubycons.

Thanks, I did wonder about the accuracy about the WB specifications because apart from the load life, they're excellent.

[tom66]

Re: Philips 42PF7320 plasma, strange problems

Should be fine. Samwha WB are crap caps and never last (possibly they lied on the spec sheet - who knows?), the power supply should work fine with the Rubycons.