Samsung PS-42D4S plasma. Has sound, no picture. Please help!

[nickBcap]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Thank you

[R_J]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

C310 = 1500µf/10v
C314 = 1500µf/10v
C104 = 100µf/35v
C33 = 1µ/50v

[nickBcap]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

I am ok with the two larger capacitors, it is the two smaller capacitor placement positions I need help with.

[nickBcap]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Hi, will I be of any help here....? I was brought this TV board because I could solder and de solder and there was bulging capacitors on the power board. Exactly the same model, Samsung Board; BN96-01217A Model Name:V3V Rev: 1.1.
So after browsing through this thread and downloading all info pics etc, trying to find out where I should place the new capacitors I thought perhaps smarter electronics repairs guys could perhaps figure out other problems concerning this TV board by showing you which capacitors I removed from the board and showing you the replacement capacitors I bought.
This began 8 years ago and I am now not sure where each of the three different (4 in total) capacitors should be soldered onto the board.
Pictures Attached

EDITED: also hoping someone can tell where to solder the capacitor replacements I bout about 6 years ago (lol) so maybe I can sell a repaired power and working power board. I will be trying to work out the correct positions on the board for the capacitors I bought.
I do not do much of this kind of repair work I am more a computer repair guy, but I am still learning little by little electronics repairs.
Thank you

[scokljat]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

I followed the post thread until the end and based on this thread I replaced the ML4824 IC1 and IR2109 IC30, but still no luck.

Based on Power Supply schematics VS_ON is coming from another board under the the main board(where the plugs are located), named LOGIC board, as you can see in the attached file(Exploded View & Part List.pdf).

Can someone help me?

Did you manage to repair it?

Regards,

Suad

[protektwar]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!



I followed the post thread until the end and based on this thread I replaced the ML4824 IC1 and IR2109 IC30, but still no luck.

Below you can see the reading from my TV:

VA = 70V OK
Vscan = -70V OK
VS = 8,57V Wrong (175V written on board)
VE = 4,49V Wrong (165V written on board)
Vset = 3,66V Wrong (165V written on board)
VG = 15V OK
VT = 33V OK

A6V = 6.11V OK
A12V = 12.94V OK
D3.3V = 3.25V OK
D5V = 5.18V OK
D6V = 6.16V OK
D12V = 12.94V OK
STD5V = 5.1V OK

B+_PFC = 400V measured between Q8S and Q6D

Stand-by VS_ON = 0.4V OK
ON VS_ON = 0.09V Wrong
Stand-by PS_ON = 3.3V OK
ON PS_ON = 0.25V OK

ML4824 when ON
PIN 1 = 3,67V | PIN 16 = 1,9V
PIN 2 = 1,27V | PIN 15 = 2,5V
PIN 3 = 0V | PIN 14 = 7,56V
PIN 4 = 3,62V | PIN 13 = 13,46V
PIN 5 = 0V | PIN 12 = 0.9V
PIN 6 = 7.56V | PIN 11 = 0.2V
PIN 7 = 2,62V | PIN 10 = GND
PIN 8 = 2V | PIN 9 =

Based on Power Supply schematics VS_ON is coming from another board under the the main board(where the plugs are located), named LOGIC board, as you can see in the attached file(Exploded View & Part List.pdf).

Can someone help me?

[ReeceyBurger123]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Ww fair play !! Very welldone to you

[Maklaud]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Awesome!

[scokljat]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help! - FIXED!

FIXED!!! :-) After replacing ML 4824 I got normal Vs and other missing voltages. TV works great, picture is fine! I really love this TV.

So, it was ML4824 after all - my first suspect! Actually, if they had IP version of IC in the local shop, I would replace it 4 weeks ago even before posting here. I'm little bit worried because I used CP version of IC as it has lower temperature range than IP, but I hope it will work for next few years...

I got following voltages:

Vs = 176V
Ve = 166,2V
Vset = 165,5V
Va = 70,1V
Vsc = -70.1V

Thank you for your help!

Cheers!

S


PS. now when I'm thinking of possible causes for this faliure, I must say I started to watch some lame Bruce Willis SF movie the night before TV died. Movie is so lame that I quit watching 15 minutes after beginning and go to sleep. Next day TV was dead. So, it must be this stupid movie! Ha?

[scokljat]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Try to change ML4824

I just bought ML4824CP1. It's a CP version which has slightly lower operating temperature range than IP version Samsung original. CP version has 0 to 70C and IP has -40 to 85C. IP version would be better because IC is located between two heatsinks, but CP is all they had in local shop for 6$. I'll try later, if it works I'll put a small heatsink on it. Stay tuned...

Thanks,

S

[Maklaud]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Try to change ML4824

[scokljat]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Try to remove the fuse (F4S) and turn on TV. VS voltage = ?

Tried to remove fuse F4S. With F4S removed I get Vs = 0.8V. With F4S installed Vs = 6V. (measured with Sus boards disconnected)

Normal Vs value for this PSU and plasma module is 175V.

Thanks,

S

[scokljat]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Is the Vs on signal that the Mainboard generates present ?

When TV is in standby VS-ON signal is 0.4V
When TV is switched ON VS-ON signal is 2.95V

When TV is in standby PS-ON signal is 3.3V
When TV is switched ON PS-ON signal is 0.25V

I measured VS-ON and PS-ON relative to RTN (chasis ground)


Thanks,

S

[scokljat]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

At voltage VS is not there a short circuit?

Short circuit test:

VS to RTN (chasis ground) - OK, open
Q1 Q2 Q3 Q4 Q6 Q8 - no shorts
D9 D10 - no shorts
F20S - OK

So, this is only simple short circuit test with DMM. If I want to test all FETs and transistors in detail I'll have to remove them from circuit which is very complicated on this PSU...


Removing F4S sounds like good idea. Will try later... but, it anything important is shorted, I suppose some fuses would blow.

Thanks,

S

[ReeceyBurger123]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Is the Vs on signal that the Mainboard generates present ?

[Maklaud]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Try to remove the fuse (F4S) and turn on TV. VS voltage = ?

[Maklaud]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

Yes..measure pin 12 relative to pin 10.

[Maklaud]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

contact closure VS on RTN.
Did you not understand?

[ReeceyBurger123]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

I think he means do the Pfc fets test ok ? Bad luck about the polly caps as well time to keep testing !!

[scokljat]

Re: Samsung PS-42D4S plasma. Has sound, no picture. Please help!

At voltage VS is not there a short circuit?

Sorry, I don't understand what exactly do you mean?