Yuraku 22" YM22RPA 2 Second to black

[VaNDAL_UK]

Hi all,

Been a lurker for about a week. Realy good forum!

I have aquired a Yuraku 22" YM22RPA monitor for very little money. This screen stays on for about 2 second and goes black. I suspected bad caps however upon inspection...

Spot the dirty burn mark? I have took continuity reading from each of the point and matched them to the other side and they all read a-OK.

Please excuse me I'm a noob when it comes to electronic's dispite being an I.T Engineer and into RC Nitro / electric Planes, Buggies & Helicopter for the last 18 years... I've replaces caps on motherboards and done minor laptop repairs I.E DC sockets.

I have a multimeter one of these http://www.amazon.co.uk/Rapitest-501.../dp/B0001NQ078

Any suggestions I would be very graitfull!!

[VaNDAL_UK]

Re: Yuraku 22" YM22RPA 2 Second to black

After a little Googleing I have found out that this monitor is identical to the ViewSonic VX2235WM-3 monitor I now have the service manual. I'm uploading the schematic's top and bottom of the power board.

Any indication on what to probe would be a BIG help!

Thanks.

[Rtech]

Re: Yuraku 22" YM22RPA 2 Second to black

The area to look at first is obviously the 'burnt' part.Put your meter on the 2000 ohm range Resistance,and measure what you get on the output transformers on the two pins on each transformer which are closest to the edges of the board...ie the other ends from the 7 pins.

[seanc]

Re: Yuraku 22" YM22RPA 2 Second to black

Are the tops of some of those caps bulging? I can't tell.

It looks like the transformer has shorted on something, what's underneath where the transformer goes?

[VaNDAL_UK]

Re: Yuraku 22" YM22RPA 2 Second to black

It's ok I think I have sorted it.

I plugged in the PSU while out of the case. I saw some smoke just a tiny wisp from the burn mark. So I cleaned it up with alcohol and began to scrape away the burnt PCB. none of the tracks had been burned. I think some how the top and bottom layers had become bridged!

There must have been something that fell into the monitor at some point and went bang! Leaving a tiny bridge. Scraping it back to clean PCB has cured it!

I'm typing this using the monitor it's been running for over an hour now. No smoke, no funny smell, no heat. All good.