Viewsonic VE500 monitor

[aradja2]

Hello,

My monitor would display briefly then go blank. I opened it up and the monitor had an obvious bad cap (C9) and I replaced it. Again, the monitor is a Viewsonic VE500 19", Model # VLCDS23722-1W. It still didn't work; no lights turned on. I decided to replace the other two caps (C12 & C13) just in case they went bad even though they displayed no visible signs of damage. The monitor still remains blank without any lights turning on. I don't know my next plan of action. Any thoughts? Thank you.

Note- I do have access to an o-scope and DMM.

[selldoor]

Re: Viewsonic VE500 monitor

We need picture of the power supply board - or does it have external ps.
Have you checked fuses? / power lead.
Does it no longer flash briefly when turned on.
What does the power indicator light do?

[selldoor]

Re: Viewsonic VE500 monitor

Answering my own questions now! - It is external PS.
Have you checked the PS - simple voltage check and voltage under load.

There is a small white smd fuse on the bottom right corner in your pic - check that.

I attach a service manual which has schematics and troubleshooting guide

It only has a 15inch panel?

[aradja2]

Re: Viewsonic VE500 monitor

I'm not sure. There's one board on the right hand side under everything and another on the lower portion under the fancy high voltage metal cage.

Upon plugging it in, no lights turn on and the display shows nothing. Pressing the power button does nothing.

[selldoor]

Re: Viewsonic VE500 monitor

Have you checked the external PS - simple voltage check and voltage under load.

There is a small white smd fuse on the bottom right corner in your pic - check that.

[aradja2]

Re: Viewsonic VE500 monitor

I just checked it and it reports infinite resistance. I'll check the manual for that type of fuse to replace it.

Thank you for that manual, but the manual schematic does not match the board... Which is extremely odd. Would you happen to have the other version? W2 or W3?

[selldoor]

Re: Viewsonic VE500 monitor

Fuse is 4A 125V - question is why did it blow?
Did you put the new caps in the correct way around (Polarity matters) and did you use like for like replacements voltage and capacitance.

As far as manuals go that is probably as good as it gets - you can trawl the net to try and find a better one. It is not odd that it does not match - in fact it is rare that they do. Its getting late over here so Im off to bed.

[aradja2]

Re: Viewsonic VE500 monitor

Thank you for all your help!

Yes, I made sure the replaced caps were in the correct polarity. Same size, capacitance, and voltage. I also replaced the fuse and nothing happened, again.

[selldoor]

Re: Viewsonic VE500 monitor

Has the fuse blown again or is it still good?


Have you checked the external PS - simple voltage check and voltage under load.

I keep asking this and you dont answer?

Cant really go on to the next step without an answer.

[aradja2]

Re: Viewsonic VE500 monitor

The fuse works fine.

Sorry! Yes, the external power supply passes both tests.

[selldoor]

Re: Viewsonic VE500 monitor

Ok With it all connected up and "on" put your meter on 200vDC and measure the voltage at the fuse. Put your black lead on the ground screw and use the red to probe each end of the fuse.

Next with the Black probe on the ground screw test the voltage at each pin
on the two connectors.
If the pins are labelled please post results like
Pin Label Actual
1 12v 12.11v
2 5v 4.87v and so on.

If they are all under 20v use the 20v scale on the meter to give a more accurate result.

There is a voltage regulator at U4 can you post the part number. If you cant read it try and clean it with little isopropyl alcohol on a q-tip