G
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Archived from groups: rec.games.pinball (More info?)
First let me start that saying yes, I understand that anything in the
negative going towards zero is actually going higher.
With that said I have 2 WPC DMD controllers doing the EXACT same thing!
Both are giving me -115 and -99 vdc and +62vdc. These readings are 10
volts too low on the negative side to illuminate the DMD. I've replaced
all of the high voltage components with those on a working board with
no change and the working board is still working so none of the
components are bad. I've also replaced the DMD with a brand new one and
tried a different controller and found that the display does indeed
light up if the negative voltages are -130 and -115.
If I remove Q4 completely the voltage goes to about -135vdc and if I
lower the resistance on R5 to about 30 ohms instead of the regular 120
ohms I get proper voltage.
My question is this. I have rung out all of the traces and there isn't
any high readings anywhere. Does, anyone have a suggestion of what
trace I should be looking at? Or should I just start jumpering them out
1 at a time to find where my weak point is?
First let me start that saying yes, I understand that anything in the
negative going towards zero is actually going higher.
With that said I have 2 WPC DMD controllers doing the EXACT same thing!
Both are giving me -115 and -99 vdc and +62vdc. These readings are 10
volts too low on the negative side to illuminate the DMD. I've replaced
all of the high voltage components with those on a working board with
no change and the working board is still working so none of the
components are bad. I've also replaced the DMD with a brand new one and
tried a different controller and found that the display does indeed
light up if the negative voltages are -130 and -115.
If I remove Q4 completely the voltage goes to about -135vdc and if I
lower the resistance on R5 to about 30 ohms instead of the regular 120
ohms I get proper voltage.
My question is this. I have rung out all of the traces and there isn't
any high readings anywhere. Does, anyone have a suggestion of what
trace I should be looking at? Or should I just start jumpering them out
1 at a time to find where my weak point is?