Eizo S2433W No Power

Thread Starter

maverick4400

Joined Aug 20, 2018
3
Hello,

I have a Eizo S2433W monitor and it has no power at all. I disassembled its power supply board and take some measurements. Since I don't have the service manual or cicuit diagram of the board, I am just trying to figure out the failing component.
By doing so I am learning a lot of things especially about measurement. I am attaching the picture of the board and some notes on it. Since I dont have any voltage at the connectors, I suspect board has some kind of a problem. May be failing mosfets. Caps looks ok as far as I understand.
I would be happy if someone can send me a service manual and also some suggestions that I should measure.

Best Regards,
Umut.
 

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MrChips

Joined Oct 2, 2009
30,706
Problems with switch-mode power supplies (SMPS) are difficult to diagnose. There are lethal voltages on that board. If you don't know what you are doing it is best to stay clear.
 

Thread Starter

maverick4400

Joined Aug 20, 2018
3
Problems with switch-mode power supplies (SMPS) are difficult to diagnose. There are lethal voltages on that board. If you don't know what you are doing it is best to stay clear.
Thank you for the warning, although I am not a professional I've been working on electronics as a hobby. I completely agree with you about the dangers and I am trying to be really careful when working this kind of circuits.
I suspect that the sleeping (may be 5V) section of the board is not working and i am suspecting the mosfets and 2 transistors (K2998) that i think oscillates the mosfets. I am not well experienced in measuring, I really appreciate some advice about measuring this kind of components.
And I have an oscilloscope but not have an isolation transformer which I am really scared off to take any measurements. That is out of my league for now :)
 

Dodgydave

Joined Jun 22, 2012
11,284
I would say the black chip at the bottom of the pcb is the oscillator, feeding the two mosfets . The preset says adj for 390V, possible for the ht for a tube.
 

Thread Starter

maverick4400

Joined Aug 20, 2018
3
I would say the black chip at the bottom of the pcb is the oscillator, feeding the two mosfets . The preset says adj for 390V, possible for the ht for a tube.
You are totally right, the black chip is MP2A5060 and i found its datasheet. I measured the voltage between pin8 and 10 and the voltage is fluctuating between 10-14Volts. (Datasheet says VCCon is 16,5V) What do you suggest should I measure more?
And I couldn't understand "possible for the ht for a tube" :( Can you please explain a little more?

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