Samsung PS-42P4H Plasma Turns on and off clicking

[retiredcaps]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

One point. Terminology is tricky on these. If you look at the long board with the Genesis chip you will see a small cable coming out the top and going behind it. The long board is the main control board, main board, or Small Signal Board, and possibly other names. The cable is the video output and goes to the main logic board. The main logic board takes the video signal and routes it to the various X, Y, and Z boards.

PlainBill

One of the naive thoughts I had when I started back in April 2010 was: geez, if I can fix these 15 or 17 inch LCDs, I should be able to fix plasmas if I can find them cheap on craiglist/kijiji.

After 4 months of reading and learning, I realize now that plasmas are a completely different beast. My calling "it" the logic board shows how far I have YET to go.

Another trip to fridge ...

[PlainBill]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

Very good set of pictures. Retirecaps is right on his description of the test point for 5V standby. That point should be at 5 volts whenever power is applied to the power supply. Measure it to chassis ground, or one of the RTN lines.

One point. Terminology is tricky on these. If you look at the long board with the Genesis chip you will see a small cable coming out the top and going behind it. The long board is the main control board, main board, or Small Signal Board, and possibly other names. The cable is the video output and goes to the main logic board. The main logic board takes the video signal and routes it to the various X, Y, and Z boards.

PlainBill

[retiredcaps]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

Found three fuses removed and checked continuity.
All looked good.

A couple of other notes.

1) My multimeter when used in continuity test (beep) will beep "good" if the ohms reading is less than 25 ohms +/- 10 ohms.

When I tested a picofuse, it beeped and I assumed the fuse was good. When I tested it with the ohms setting, it read 19 ohms. As I later found out, that is a bad fuse. A good fuse should read 0.3 ohms.

I don't know what the Fluke specs are, but if you are using continuity, you may have a false sense that the fuse is good.

2) There may be fuses on all your boards. I didn't look through all your pictures in great detail, but it wouldn't surprise me to see at least one fuse per board.

[retiredcaps]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

I am not sure where or how to check for standby and secondary voltages?

It looks like CN842A has the connection for STD-5V. This is one of voltages we are interested in.

Since this is a plasma with very high voltages, I'll let PlainBill describe how to measure for this voltage. I'm 99% sure I can safely describe it, but PlainBill can do it better.

The logic board is the bottom one with the big Genesis chip on it.

[DigitalRambler]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

Wow thanks Gents for the quick reply

I did check all caps for voltage to make sure they were discharged.

Found three fuses removed and checked continuity.
All looked good.

I am not sure where or how to check for standby and secondary voltages?

I have attached several pictures of all of my boards.
Let me know if you need to see more pictures.
Also I have set up a picasa web album that has higher resolution images

Thank you!

http://picasaweb.google.com/Digital....eat=directlink

[PlainBill]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

To add to what retiredcaps said, pictures of the power supply would help. Also, most of these supplies have the output voltages labeled. The first experiment would be to use your Fluke to measure the standby voltage (probably labeled 12VS, 5VST, 6VSBY, or something like that), then check the other outputs to see if any are coming up when the relay clicks.

A common cause of this type of failure is a short on either a sustain board or a buffer board (or both) that overloads the power supply.

PlainBill

[retiredcaps]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

Samsung PS-42P4H1 42" Plasma
Power supply# BN96-01047A (PSC10071J M)

PS. Pictures of all your boards would help too. Attach your pictures using this method ...

https://www.badcaps.net/forum/showthread.php?t=1868

[retiredcaps]

Re: Samsung PS-42P4H Plasma Turns on and off clicking

I have a good Fluke 189 meter that can check capacitance.

With the board removed I have checked a few caps in circuit but for a 4700 uf 10V cap I get 8.25 MF.

I know it would be best to check the caps out of circuit.

The correct way to check capacitors with your Fluke is to remove the caps from the board. Also, the big caps like 47 uF 450v should be DISCHARGED first other you may get a shock or kill your Fluke.

However, instead of pulling caps, check to see if you have standby voltage first. Depending on the TV, it is probably 5V DC or it can be 12V DC.

If you get stable standby and secondary DC voltages, we can assume that your power supply and caps are probably alright.

Also, check your board for blown fuses. If a fuse is open, test the transistors, mosfets around it to see if that was the root cause.

If you need help testing any of this, just ask.

[DigitalRambler]

Hello I have a Samsung PS-42P4H1 42" Plasma
Power supply# BN96-01047A (PSC10071J M)

It tries to turn on, but a relay just keeps clicking.
The screen never actually turns on.

I have repaired several computer LCDs before so I am not a complete noob, but I am new to the bigger stuff.

I have the tv apart and searched every board for signs of a blown cap.
But haven't found any leaking or bulging.
I have always been lucky before the culprit capacitor was very obvious.

From my research I am guessing the trouble probably lies with the power supply board. But with no visible indication of which capacitors is bad I do not know where to start.

I have a good Fluke 189 meter that can check capacitance.
With the board removed I have checked a few caps in circuit but for a 4700 uf 10V cap I get 8.25 MF.
Which doesn't seem right but I am not sure If I understand what that is telling me. When I check a bigger cap like a 47 uF 450v I show 450 uF on the meter. Meter is set to auto range.

So first maybe someone could explain what my meter is telling me. Google hasn't been much help so far.

When I check the resistance they build to infinity.

I know it would be best to check the caps out of circuit. But I do not want to just start pulling capacitors off and checking them if it is not necessary, as that could lead to more problems then I started with.

So my real second questions is where should I start? How can I narrow it down?

Thanks in advance for any help anyone can offer.