Chimei CMV 938 D

[limkopi]

The monitor required a long warm-up time, until one time when I turned to max brightness for too long. There was a snapping sound and the monitor turned black, with a very dim image still visible. I opened the monitor up and true enough, the caps were bad and all were replaced. Didn't work. The ICs at the blackened spots were replaced, and still didn't solve the problem. The screen was still dim and image slightly visible.

Photo of the boards included.

[selldoor]

Re: Chimei CMV 938 D

So it still does 2 seconds to black?
Does the power led stay lit
Can you see a very dark image on the screen - connect to pc showing a known picture.
Can you post a picture of the back of the power supply - needs to be clear and in focus.

[stj]

Re: Chimei CMV 938 D

could be the tubes,

do you have any spare cfl lamps you can connect to the 4 white connectors on the left?

[limkopi]

Re: Chimei CMV 938 D

It still does 2 seconds to black after replacement. Power LED stays lit. Picture dimly visible

Not sure what CFL Lamps are and how I should use them for tests.

picture of back of power board attached. I hope this is clear enough.

[stj]

Re: Chimei CMV 938 D

CFL are tiny flourescent lamps that are inside the display panel,
they plug into the 4 connectors on the left to light the display.

[selldoor]

Re: Chimei CMV 938 D

Ok see picture and test the secondary windings on the inverter transformer.
I have marked where I think they are. Set your meter on ohms 2000 and with NO power to the board test S1 to S2 and S3 to S4. - You may need to scrape of the glue/lacquer to get a contact.

I have also marked some joints that dont look great. We often suggest re- flowing all these high voltage joints - all the ones on the transformer and
those on the blue caps and the lamp sockets.

[limkopi]

Re: Chimei CMV 938 D

Finally got some time to get the tests done. The results were about 760 Ohms on both S1-S2 and S3-S4.