Chesterfield, MO
Just curious, are the voltages to it correct?
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
(Topic ID: 146911)
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Yes...that's good. I want to know if the board is causing the two negative high voltages to draw together.
I just fixed a DMD with this same issue.
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
Quoted from balboarules:260 taking both CPUs to be checked
Ouch. Seems high depending on the repair necessary.
Quoted from balboarules:So you fixed the dmd itself?
The electronics on the display. Documented here.
http://www.pinwiki.com/wiki/index.php?title=General#DMD_Display_Panel_Repair
Quoted from falco:Can you check the voltages on the power connector that plugs into the DMD panel itself? There are two rails, one at about -108V and the other at about -120, that Chris is talking about. It's possible that the DMD panel itself is pulling them to the same voltage, which is bad.
Exactly.
How to test voltages...
http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Testing_DMD_Controller_Power
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
Those voltages are too high. While they might work, in the past when I've seen voltages that high, the display would have a "plasma affect" where images that were supposed to be on the display would have surrounded by dots that were not supposed to be lit. And, while I can't say with certainty, those high voltages may be a factor in the death of that display panel.
I'd take a look at the HV section of the dot controller card.
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info
I note that pins 7 and 8 have a 22V difference. This should be only 12V. If you didn't have a display connected when you took the measurement, those voltages would be about right as the lower of the two negative voltages often tests low when not under load. Also, pin 2, is supposed to be about 12VDC.
Shoot a picture of the back of the display. I want to see what kind of row and column drivers it has on it.
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
In your DM, the voltage readings with a known working display connected are normal, right?
It's the Problematic Babcock display that causes the lower negative voltage to vary from nominal, right?
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
One of those ICs on the back is FUBAR.
I can't say which one.
I'd get an identical display and do some probing around. It's the same design that Vishay/Dale used.
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info
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