Samsung PS-42P4H Plasma Turns on and off clicking

[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.

[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.

[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

[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

[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

[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.

[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.

[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

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 ...

[DigitalRambler]

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

Thanks Guys

Checked the fuses again all are about .35 ohms.
Couldn't find anymore.

Checked for voltage at the CN842A test point. But there was none.
I tested it using several screws as ground, an RTN point near CN842A and some of the RTN points in a couple of the plugs.

I thought the relay was kicking on and off but, it only clicks on once then shuts off.

Let me know where to head next.

Thanks for the advice

I was kind of hoping that this would be as easy as a monitors too, but knew it was probably going to be more of a challenge. I just really want to learn how to fix it.

[DigitalRambler]

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

Ok did some more checking.

I think I was checking at the wrong place.
I checked at the bar where the CN842A was writing on the board.
There is not any voltage there.

But I looked around and the connector and realized it said STD-5V.
I couldn't see it with the plug in.
So with the connector plug in I checked the votagle in the connector and there was a solid 5V there.

Thanks

[PlainBill]

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

Ok did some more checking.

I think I was checking at the wrong place.
I checked at the bar where the CN842A was writing on the board.
There is not any voltage there.

But I looked around and the connector and realized it said STD-5V.
I couldn't see it with the plug in.
So with the connector plug in I checked the votagle in the connector and there was a solid 5V there.

Thanks

That's as expected. And the fact that the relay clicks indicates that the power supply is being turned on. The next step would be to check the other output voltages. Since the relay clicks only once (and then presumably opens), it's not likely you will be able to get a stable reading, but it will be good to know if none of the other outputs come up, some of them come up, or (best of all), all but one come up.

PlainBill

[DigitalRambler]

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

Thanks PlainBill

What other outputs?

Where would I find them on the board?

I sure wish I could find a service manual for this thing.


Thank you

[retiredcaps]

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

What other outputs?

Where would I find them on the board?

The other outputs are the other voltages like 12V, 3.3V and 19VDC depending on the design. They will be written down on the PCB right next to all the connectors (those that start with CN).

Same as the 5VC STD as before.

[DigitalRambler]

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

ok thanks

[DigitalRambler]

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

Any connector that said 3.4v only had .4

I didn't find any 12v on the power supply board.
But I did find 2 on the board to the left of the power supply board.
There was 0v

I didn't find any connectors marked higher then 12

There are a serval voltages written near the bottom of the power supply ranging from 3.4. 5, 12 14, and 33
but there are no connectors near buy just some bars.

If I unplug the tv and wait a minute, then plug it back it, while the relay is on I get 12v and 3.4v, on the connectors, but that only lasts a few seconds.
Also get the same response on two white wires that are 5v volts on the left side of the power supply.

In order to get the relay to kick on I have to wait about a minute with it un-plugged.

thanks

[PlainBill]

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

Any connector that said 3.4v only had .4

I didn't find any 12v on the power supply board.
But I did find 2 on the board to the left of the power supply board.
There was 0v

I didn't find any connectors marked higher then 12

There are a serval voltages written near the bottom of the power supply ranging from 3.4. 5, 12 14, and 33
but there are no connectors near buy just some bars.

If I unplug the tv and wait a minute, then plug it back it, while the relay is on I get 12v and 3.4v, on the connectors, but that only lasts a few seconds.
Also get the same response on two white wires that are 5v volts on the left side of the power supply.

In order to get the relay to kick on I have to wait about a minute with it un-plugged.

thanks

As you indicated, a service manual would be a big help. It appears this TV has a main supply (big green board almost smack-dab in the middle) and an auxiliary supply just to the left of it (tight tan board). There is a white label near the upper right corner of the panel. It lists a number of voltage identifiers (Va, Vs, etc). These voltages go to the Y (left side) and Z (right side) sustain cards. Check those voltages. Again, they would only be present for the time between the first relay click and the second.

It APPEARS the power supply is working, at least in part, but the main controller (small signal board) is detecting an error and shutting the power supply down. The fact you have to unplug power for a minute or two is normal. Once it detects a fault and shuts down the main supply it ignores all attempts to turn the supply back on until the power is reset by unplugging it.

PlainBill

[DigitalRambler]

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

My Label Says (see attached pic)
VA Vsc VS Ve Vset
70 -60 170 160 157

I measured all votages on all of my power supply connectors on both the main
Power Board and the little one to the left.

Sorry for the long post.
Voltages

Main Power Board
CN805 (Left)
VS 2.4
VS 2.1
RTN
RTN
VSet 0
RTN
VScan 0
RTN
Vg 15
D5v 5.3

CN804 (Right
VS 2.8
VS 2.8
RTN
RTN
Ve 2.6
RTN
Vg 15
D5v 5.3

CN806 (Left)[/B]
5 0
RTN
RTN
Va 0
Va1 0

CN812 (Right)
5 0
RTN
RTN
Va 0
Va1 0

CN842A
RTN
Fan3 0
Fan2 0
Fan1 0
RTN
STD-5v 5
Them-D .04
Vm-UV .27
oV 5.4
PS-ON 3.3 when unplugged .5 plugged in
VT 33

CN841A
RTN
RTN
D3.4v 3.38
RTN
VmIN 16.7
RTNa 0
Amp 21.6

CN803
RTN
VS-ON 0
N.C 0
N.C 0
RTN
D5.3v 5.3
RTN
RTN
D3.4v 3.38
D3.4V 3.38

Second Power Supply Board
CN801
RTN
VT 33
RTa 0
RTa 0
amp 18.3
amp 18.3
RTN
A12V 12
RTN
A6V 6

CN802
Fan on/off 3.34
Std-5V 5
RTN
PS-ON 2.78 unplugged / 0 plugged in
D12V 12
RTN
RTN
3.4v 3.38
3.4V 3.38
RTN
D6V 6

[PlainBill]

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

I'll be honest with you, I don't get the warm, fuzzy feeling that you and I are communicating adequately. I DO get the feeling that you are trying to give me the information I need. (This is a welcome contrast to others who always seemed to want to go off on a tangent and discuss everything EXCEPT answering my question.)

On the left side of the main power supply are two connectors, a ten pin (Y-Sustain), and just to the right of it, a nine pin (Z-sustain). There are also two 5 pin connectors directly below these two connectors (top and bottom X drivers). The next-to-the-bottom pin on the 9 pin connector is labeled Va or Vs, I can't quite figure out which.

I may have mentioned this already, but it bears repeating. There are potentially lethal voltages present on this power supply. These can present a life-changing (or life-ending) experience. Always keep at least one hand in your pocket when working on the power supply and wait 2 minutes after unplugging the power cord before touching the power supply.

Step 1. With the power cord unplugged, improvise an adapter so you can hook the + (red) probe of your DMM to the Vs (Va?) pin. I use a dissecting pick jammed into the connector; some connectors have enough room you can stick the meter probe in far enough to make contact. The - (black) probe should be hooked to ground. I usually just stick it into one of the unused mounting studs on the plasma panel. Set the DMM to the 200 VDC range.

Step 2. Plug in the power cord and turn on the TV. Does the DMM show any change in voltage? How high does it go?

Step 3. Once the relay clicks again, unplug the power cord, wait at least two minutes.

Step 4. Disconnect the two 5 pin (X drivers) cables.

Step 5. Plug in the power cord and turn on the TV. Does the DMM show any change in voltage? How high does it go?

Step 6. Once the relay clicks again, unplug the power cord, wait at least two minutes.

Step 7. Disconnect the 9 pin (Z-Sustain) cable at the Z-Sustain card.

Step 8. Plug in the power cord and turn on the TV. Does the DMM show any change in voltage? How high does it go?

Step 9. Once the relay clicks again, unplug the power cord, wait at least two minutes.

Step 10. Disconnect the ten pin Y-Sustain cable at the Y-Sustain card.

Step 11. Plug in the power cord and turn on the TV. Does the DMM show any change in voltage? How high does it go?

Step 12. Once the relay clicks again, unplug the power cord, wait at least two minutes.

Step 13. If the power supply came up to full voltage and the relay did not click the second time the module you have just disconnected is at fault. If the power supply never came up to full voltage, the power supply is at fault.

PlainBill

[DigitalRambler]

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

Sorry trying hard to give you the info you need. I really appreciate your help.

Thanks for the reminder about the voltages, I have been tearing apart electronics since I was pretty young, and have grabbed the wrong thing a time or two and got bitten. So I am really careful now. : )

The second to the bottom pin on the 9 Pin connector (CN804) is labeled Vg.
Pressing power button does not make difference on any test
Step 2. = 15V
Step 5. X Drivers unplugged = 15V
Step 8. Z Sustain unplugged = 15V
Step 11. Y Sustain unplugged = 15V

The Top Two pins on the 9 Pin connector (CN804) are labeled VS
Tested both pins and they were the same on all tests.
Pressing power button does not make difference on any test.
Step 2. = 2.8V
Step 5. X Drivers unplugged = 2.8V
Step 8. Z Sustain unplugged = 1.7V
Step 11. Y Sustain unplugged = .7v

The second to Last pin on the right Z Driver connector (CN812) is VA
It was 0v on all tests.

I have included better pictures of the CN804,CN805,CN806,CN812 connectors
CN805 Left 10 pin Y Sustain
CN804 Right 9 Pin X Sustain
CN 806 Left X Driver
CN812 Right X Driver

You can also find more images in my picasa album at higher res.
http://picasaweb.google.com/Digital....eat=directlink

Thanks for your help Hope I gave you what you needed to know