Hello all and first off, thank everyone for the wealth of information within this forum. Your help to people like me is very much appreciated. After reading this forum daily for the past few weeks I decided to make the plunge into repairing my Samsung Syncmaster 940BX.
monitor status...With monitor on, no vga cable hooked to computer, have blue power light. This does not change at all.
The problem...."Digital" box appears on screen for 1 or 2 seconds, disappears and then the "no cable attached" box appears and starts to move up screen. Then the backlights switch off.
From power on until backlights switch off is 18 seconds.
What I have done so far
- I replaced 5 caps on power/inverter board with multiple Panasonic FM and one FC caps from Digikey. None of the original caps had any bad signs but replaced anyhow.
- resoldered any joint I thought looked even slightly needing it. Used mag glass to check joints.
There was no change in problem after install new caps.
My measurements....120V input
Big Cap= 172.3V DC across legs
Power connector out to logic board pins 1-9
1- BDIM
2- 14.45V
3- GRD
4- GRD
5- GRD
6- 5.18V
7- 5.18V
8- ADIM
9- ON/OFF
Cap specs 1 thru 5 ( numbered in pic)
1- 330uf 16v 105
2- 1000uf 16v 105
3- org was 68uf 25v 105, replaced with 68uf 35v 105
4- 100uf 450v did not replace
5+6- 1000uf 25v 105
I have double checked all my caps for correct polarity on board.
Attached are front and rear of power/inverter board and monitor sticker info.
I have read many, many of the threads but I am now stumped and need some help from all of you knowledgable guys. Up until now I was hopeful it only needed caps but it must be something more.
I need someone to point my in the right direction or step me through it.
monitor status...With monitor on, no vga cable hooked to computer, have blue power light. This does not change at all.
The problem...."Digital" box appears on screen for 1 or 2 seconds, disappears and then the "no cable attached" box appears and starts to move up screen. Then the backlights switch off.
From power on until backlights switch off is 18 seconds.
What I have done so far
- I replaced 5 caps on power/inverter board with multiple Panasonic FM and one FC caps from Digikey. None of the original caps had any bad signs but replaced anyhow.
- resoldered any joint I thought looked even slightly needing it. Used mag glass to check joints.
There was no change in problem after install new caps.
My measurements....120V input
Big Cap= 172.3V DC across legs
Power connector out to logic board pins 1-9
1- BDIM
2- 14.45V
3- GRD
4- GRD
5- GRD
6- 5.18V
7- 5.18V
8- ADIM
9- ON/OFF
Cap specs 1 thru 5 ( numbered in pic)
1- 330uf 16v 105
2- 1000uf 16v 105
3- org was 68uf 25v 105, replaced with 68uf 35v 105
4- 100uf 450v did not replace
5+6- 1000uf 25v 105
I have double checked all my caps for correct polarity on board.
Attached are front and rear of power/inverter board and monitor sticker info.
I have read many, many of the threads but I am now stumped and need some help from all of you knowledgable guys. Up until now I was hopeful it only needed caps but it must be something more.
I need someone to point my in the right direction or step me through it.
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