Author Topic: Need help getting some LCD monitors running  (Read 2499 times)

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Offline Jeremy Briddle

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Need help getting some LCD monitors running
« on: December 28, 2012, 11:55:17 am »
Hello. I've collected a bunch of busted LCD monitors from work and I'd like to get at least one of them running. They all have some kind of internal damage that the engineers couldn't fix so they were going to throw them out. So far I have 6 monitors. I tested them and wrote down the symptoms below. If I can get one working I'd be glad to give the rest away to others to fix.

1. HNC iF281D, VGA and HDMI: Works for a few moments, goes blank then comes back on with a frozen and scrambled image.

2. ViewSonic VX2235wm, Model VS11349, VGA and DVI: Powers up and works fine for a moment. Then the screen turns bright white.

3. Acer AL1916W-A, VGA and DVI: Works for several seconds to several minutes then goes blank. The power light remains solid green.

4. HNC iH283, Model HSG1081, VGA DVI and HDMI: Power light turns on and glows solid green. Screen remains blank.

5. Samsung SyncMaster 225BW, VGA and DVI: Power light flashes in tandem with a high-pitched squeal. Screen remains blank.

6. Princeton LCD1911, Model LE1915, VGA: Won't power up. Possibly a power plug and/or power supply issue.

Offline Steve Bowtie

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Re: Need help getting some LCD monitors running
« Reply #1 on: December 28, 2012, 01:59:46 pm »
It's likely that 3, 4, and 5 are the high voltage supply for the back light. One way to check is to connect the monitor and shine a very bright light at the screen and see if there is any hint of an image, indicating that the LCD is still good but the back light is dead. As for the first two, they're dead Jim (unless it's a common issue or you are a component level troubleshooting BADASS).

Offline scuba840@yahoo.com

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Re: Need help getting some LCD monitors running
« Reply #2 on: December 28, 2012, 02:19:09 pm »
1 - TRASH
2 - Unknown, but probably NOT a good candidate for repair.  You might try recapping the low voltage power supply, but unlikely.
3,4,5 probably the high voltage power supply for the backlight.   If these are backlight by  florescent bulbs, rather than LED, then perhaps recapping the power supply ***might*** fix the problem.  the Aluminum electrolytic caps like to go bad on these.
6 I agree probably a low voltage power supply issue.  Check the diodes on the switcher power supply  and then the electrolytic caps. 

I just tried to replace the florescent bulb on a nice monitor, but no dice,  I had to remove the LCD panel and that flexible ribbon cable that joins to the glass can endure zero flexing before connections start to go bad and you have lines on your screen. 

I have an in circuit electrolytic  cap checker, but I live up in Oro Valley.  Depends how motivate you are to get it....

Neill