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Main => Monitor/Video Forum => Topic started by: srarcade on October 12, 2009, 03:45:00 pm

Title: WG 4900 Fades To Black
Post by: srarcade on October 12, 2009, 03:45:00 pm

I have a WG 4900 that after being powered on for a minute or so fades out to black. Seems to still have some faint neck glow after picture is gone. It looks like it was capped already, so I went ahead and replaced transistors Q303 and Q304 since they seemed possibly troublesome but it did not work. Any other ideas of troublesome components to look for?

Thanks!

Title: Re: WG 4900 Fades To Black
Post by: SirPeale on October 12, 2009, 05:21:21 pm

Are you absolutely sure it was capped?

Check for cold solder joints.  Solder everything within reason.

Title: Re: WG 4900 Fades To Black
Post by: srarcade on October 13, 2009, 05:27:56 pm

Looking at the caps, i can see most of them look newer, a few originals are still on the board. I can always cap it again, very cheap and quick to do, and I can guarantee my own work  ;D

Thanks!

Title: Re: WG 4900 Fades To Black
Post by: Kevin Mullins on October 13, 2009, 06:32:51 pm

Describe the "fade" to black issue again.... like gradually fades to black or does it just come on and then go black instantly ?

Trying to visualize anything I have seen "fade" to black.
(aside from a little Metallica)  ;D

Title: Re: WG 4900 Fades To Black
Post by: srarcade on October 15, 2009, 01:32:14 pm

Quote from: Kevin Mullins on October 13, 2009, 06:32:51 pm

Describe the "fade" to black issue again.... like gradually fades to black or does it just come on and then go black instantly ?

Trying to visualize anything I have seen "fade" to black.
(aside from a little Metallica)  ;D

Well after I power it on, it takes a minute to warm up and then the fade starts and takes all but 5 seconds to fade to black. This process used to take 30 minutes.. then 10.. then 5.. now its soon as it gets warm.

Thanks!

Title: Re: WG 4900 Fades To Black
Post by: Kevin Mullins on October 16, 2009, 11:38:32 am

Just for kicks..... after it fades to black wiggle or turn the SCREEN pot on the flyback and see if that has any effect.

And like Peale mentioned, check EVERY solder joint including connector header pins, etc.
Nothing worse than chasing a "component" problem to find out later it was a bad solder joint or cracked trace. (this is usually the first thing I do to a chassis anymore)

Title: Re: WG 4900 Fades To Black
Post by: srarcade on October 16, 2009, 11:48:26 am

Ok, i'll give that a try. I was playing with the screen before to get it looking better while it was working I wonder if that kick started this whole thing. It worked (not well but worked) before I started making adjustments to it.

Title: Re: WG 4900 Fades To Black
Post by: cw on October 16, 2009, 09:57:07 pm

had one doing this a few years back... check for cold solder on neck pcb