Samsung Spn4235 No video or sound

[TechShui]

Re: Samsung Spn4235 No video or sound

No I don't think those two caps are the problem.

Tom66 said he was just guessing, because some newer Samsung TV have a common problem with a pair of 10v 3300uf caps. (tom, if you're reading this please confirm).

Maybe something in the sustain boards is shorting VS? Did you test VS while it was plugged into the sustain boards? Try it both ways see if anything changes.

Maybe there's a Voltage Regulator somewhere on the power board that's gone bad. It'll be in the VS circuit. A service manual will have diagrams to help identify the circuit.

Here's another thing you could do:
Find the original fuses (hopefully you didn't throw them away) that you removed from this TV.

Test all 3 of them with your multimeter set to continuity.

If the fuses are good, you'll hear a beep. If one or more is bad, you won't hear anything. --means one of the original sustain fuses is blown.

You can also do this with the fuses that are in the TV now, just to make sure they're alright.

[lilmonk3]

Re: Samsung Spn4235 No video or sound

Ok all.. I am working on getting some better pics but I will have to use my adroid.. Because my damn sis hasnt returned my canon rebel..I did do some more volt test.. The VS going to y and x board is VERY LOW.. 33v on both sides of power supply.. I will be placing an order later today for those 2 smaller caps that are circled in an earlier post.. Do you all think it could be those caps?

[TechShui]

Re: Samsung Spn4235 No video or sound

Plugged in then turned the TV on before I measured.

But selldoor is right, if your black probe moved off ground, you would get 0.00V everywhere.

And good pictures would help ;-)

I still suspect Y-sustain and/or Y-buffers. Anyone else agree? :hmm:

[lilmonk3]

Re: Samsung Spn4235 No video or sound

No back light at all.. Just checked in a pitch black room.. Also when you took your readings, did you just only have the power plugged in, or did you hit the power button then test?

Edit: Just saw your post retiredcaps, thanks for clearing that up.
Looks like they failed because of how close they are to that heatsink.Really? No backlight, not even in a dark room?

My backlight turns on, right around the 2nd of the 5 blinks.
The backlight/TV stays on too, until I hit power button, LOL

The fact that you have no backlight could indicate a Y-sustain problem.That's another difference between your TV and mine: With either (or both) of the sustain boards disconnected, I get the same readings (never "zeros all the way across").

My readings are fine. They match up with the markings on the boards. And they match the readings you took with everything connected.

What you call cn1 is cn801, the plug from the PS to the analogue board, right? That plug shouldn't even be affected by disconnecting a sustain. It makes no sense to me, but maybe someone has seen that problem before.

[selldoor]

Re: Samsung Spn4235 No video or sound

@lilmonk3 - Looks like voltage good - though nils are a query-did you hold the probe or could it have moved off ground - Desperate need for good photos.

[TechShui]

Re: Samsung Spn4235 No video or sound

Edit: Just saw your post retiredcaps, thanks for clearing that up.
Looks like they failed because of how close they are to that heatsink.

There is no screen flash .. Just the standby light blinks 5 times

Really? No backlight, not even in a dark room?

My backlight turns on, right around the 2nd of the 5 blinks.
The backlight/TV stays on too, until I hit power button, LOL

The fact that you have no backlight could indicate a Y-sustain problem.

Selldoor after reading one of your above post, I noticed that you said to test the voltage WITH the x and y disconnected.. The voltage that I listed above I think were taken with cables connected.. I have since retested with the y and x boards and the voltage on cn2 is the same, but cn1 reads zeros all the way across..

That's another difference between your TV and mine: With either (or both) of the sustain boards disconnected, I get the same readings (never "zeros all the way across").

My readings are fine. They match up with the markings on the boards. And they match the readings you took with everything connected.

What you call cn1 is cn801, the plug from the PS to the analogue board, right? That plug shouldn't even be affected by disconnecting a sustain. It makes no sense to me, but maybe someone has seen that problem before.

[retiredcaps]

Re: Samsung Spn4235 No video or sound

Can anyone say whether high votage (450v) caps actually come in a Low-esr version?

The big filter cap doesn't work as hard. See

https://www.badcaps.net/forum/showthread.php?p=177869

[TechShui]

Re: Samsung Spn4235 No video or sound

I'm almost certain now, that got what I ordered.

A quick search on DigiKey, with the values 330uf and 450V gives 3 pages worth of results ALL of the results are "General Purpose", except for two that say "Audio".

Can anyone say whether high votage (450v) caps actually come in a Low-esr version?

As for the problem you're referring to, do you mean this? See: http://blog.coppelltvrepair.com/2010...o-picture.html

Dell uses Samsung parts in their plasmas. Samsung's product line was also affected. However those power supplies are much newer (around 2006+).

This SPN4235 model is a late 2003 model, and uses a different power supply. Of course that does NOT guarantee that they're aren't more bad capacitors on this board.

Makes me wish I had a capacitance meter, so I could see for myself

[tom66]

Re: Samsung Spn4235 No video or sound

I'm not sure - I have only serviced one Samsung plasma and it was one of the newer ones. However, I have heard others referring to two caps of the same size and rating right next to each other that fail on PSUs like this.

What caps did you order from Digikey - did they send you those? What do they look like? Generally, I've found Digikey to be very reliable.

[TechShui]

Re: Samsung Spn4235 No video or sound

Take voltages on other connector.

Try switching on with the x board disconnected report what happens
Reconnect x board and disconnect y board report what happens.
Try with both disconnected and report.


Then take the voltages voltages without the x y boards
connected. Both connectors on the power board

Did you replace all the caps or just the big ones.
Tom referred to some small ones in post#2 that cause problems.

Wow this thread is growing nicely.

My caps arrived today (450V 330uf), and I'm not sure but I think DigiKey might've sent me the wrong ones? I think they're General Purpose instead of Low-esr.

I installed them and now have the 5-blink pattern just like lilmonk. For clarification, the TV used to turn on with original caps, despite the fact they were bulging... weird, huh?

Tom66,
Were you referring to the two caps I circled in the photo below?

The green one on the left is a SSL 450V 22uf, the smaller Nichicon on the right is a 10V 2200uf.

[lilmonk3]

Re: Samsung Spn4235 No video or sound

Selldoor after reading one of your above post, I noticed that you said to test the voltage WITH the x and y disconnected.. The voltage that I listed above I think were taken with cables connected.. I have since retested with the y and x boards and the voltage on cn2 is the same, but cn1 reads zeros all the way across..

[lilmonk3]

Re: Samsung Spn4235 No video or sound

There is no screen flash .. Just the standby light blinks 5 times

With x board unhook, with y board unhooked, and with both unhooked.. All came back with same results.
Do you mean when you switched on with the boards disconnected the start up and power light and and screen flash was the same as with them connected.

Most of the voltages look ok to me but we need more input from members who know more about plazma tvs.
There should be more fuses but untill we get the pics of all the boards im stuck.
There may be one on each of the x y boards.

[lilmonk3]

Re: Samsung Spn4235 No video or sound

With x board unhook, with y board unhooked, and with both unhooked.. All came back with same results.
Do you mean when you switched on with the boards disconnected the start up and power light and and screen flash was the same as with them connected.

Most of the voltages look ok to me but we need more input from members who know more about plazma tvs.
There should be more fuses but untill we get the pics of all the boards im stuck.
There may be one on each of the x y boards.

There are 250v 8a fuses on the x and y boards and yes I changed those and the one on the main board.. Yes it does the same 5 blinks with those boards unhooked like I listed them...

[selldoor]

Re: Samsung Spn4235 No video or sound

With x board unhook, with y board unhooked, and with both unhooked.. All came back with same results.
Do you mean when you switched on with the boards disconnected the start up and power light and and screen flash was the same as with them connected.

Most of the voltages look ok to me but we need more input from members who know more about plazma tvs.
There should be more fuses but untill we get the pics of all the boards im stuck.
There may be one on each of the x y boards.

[lilmonk3]

Re: Samsung Spn4235 No video or sound

Ok I did some test..
With x board unhook, with y board unhooked, and with both unhooked.. All came back with same results. Also check cn1 and cn2 photos attached.
Cn1 Starting with Blue Wire
0.3
32.7
0.2
0.3
13.14
13.13
1.0
12.89
1.1
6.1

Cn2 Starting with blue wire
4.43
5.02
1.3
.465
12.89
1.4
1.4
3.3
3.4
1.4
6.1

[lilmonk3]

Re: Samsung Spn4235 No video or sound

Edit is not an option.. Its a large board so it might take several pics of in very close up shots .. But I will get them as soon as I finish these volt checks..

[selldoor]

Re: Samsung Spn4235 No video or sound

Same pictures resized? Just to show the problem - I have enlarged one of yours and one of the examples I gave earlier to the same extent. If we are looking for faults/problems we need to be able to see it the same as if you were looking at it through a magnifying glass.


To remove pictures just click on edit -if it is still available.
then "go Advanced" then "Manage attachments"

you will see a remove button.

[lilmonk3]

Re: Samsung Spn4235 No video or sound

Just the 4 big ones as 2 of them were blown..I will work on getting the readings now.

Take voltages on other connector.

Try switching on with the x board disconnected report what happens
Reconnect x board and disconnect y board report what happens.
Try with both disconnected and report.


Then take the voltages voltages without the x y boards
connected. Both connectors on the power board

Did you replace all the caps or just the big ones.
Tom referred to some small ones in post#2 that cause problems.

[lilmonk3]

Re: Samsung Spn4235 No video or sound

Well I couldnt figure out how to delete those pics.. And I made them small like that because it kept erroring out like it didnt like the larger ones.. So here are larger ones..

[selldoor]

Re: Samsung Spn4235 No video or sound

Take voltages on other connector.

Try switching on with the x board disconnected report what happens
Reconnect x board and disconnect y board report what happens.
Try with both disconnected and report.


Then take the voltages voltages without the x y boards
connected. Both connectors on the power board

Did you replace all the caps or just the big ones.
Tom referred to some small ones in post#2 that cause problems.