Pac / WG4900 White Band at Top of Screen

[howitzer]

Hi Guys,  I recently picked up a Pac Man machine with a WG4900 monitor.  The monitor had just been re-capped and everything worked great for a while.  After a while a white band appeared at the top couple of inches of the screen and pretty much everything else is gone (see attached)..

The game coins up and seems to play fine.  You can sometimes catch a very faint image of the game.  The same white band is visible when the board is disconnected.

Any advice as to what I can try?  I have no experience with monitors, so I'd like to avoid the newbie mistakes if possible.

Thanks.

[Ken Layton]

This chassis is well known for many bad solder joints. So even if it has just had a capkit installed, whoever did the work should have checked it over and re-soldered any bad joints.

[howitzer]

OK thanks.

[bjk7382]

I had a wg4900 that lost all vertical deflection because of one bad solder joint on a resistor, so check it carefully

[howitzer]

Thanks,  I hope to have some time this weekend.. as good a time as any to work on my soldering skills... 

John

[howitzer]

Hello all,

I managed to discharge and disassemble the chassis using the information in the FAQ.  I'm looking for bad solder joints, but since this is the first time I've tried this, I'm not too sure what to look for.  Some of the joints do have a bit of corrosion.  Should these be redone?  Is there anything else that I should be checking for?

Also,  are there specific spots on the board I should check that If bad would cause the problem I'm having?

Thanks much.