Arcade Collecting > Pinball
High Voltage not high enough
Neverending Project:
My displays on my Stern Flight 2000 are not lighting. It is most likely because the regulated HV test point is only reading 145V, and it should be >155V. The problem is that I can't adjust it with the variable 25K-Ohm resistor - it doesn't do anything.
I have rebuilt the entire voltage regulator, and all the test points look good without any load (connectors J1 and J3 removed). When I then connect J1 and J3 to the regulator, and remove all but J3 and J4 from the SDU-100, the HV at TP2 only reads 145V. The unregulated HV at TP4 reads about 260V. But turning the variable resistor at RT1 has no effect. I know the resistor is fine because it is brand new, and I can probe the solder points on the back and see the change in resistance as I turn the screw.
I have also rebuilt the entire 5V and HV sections of the SDU, replacing just about every part on there (including the filter caps and Q21 and Q23). Any thoughts on where to trouble-shoot?
Thanks.
ChadTower:
Did you rebuild the connectors? Something is resisting more than it should or leaking to where it shouldn't... but since you rebuilt everything odds are that you've got an over resistance in that circuit. Best guess is the connectors.
Neverending Project:
I replaced the header pins on both the regulator and the SDU, and the connector on the regulator. I suppose I can replace the connector to the SDU also (it is not brown or burned at all), but if there is extra resistance somewhere, shouldn't changing the variable pot still change the HV at the test point, even if it is low overall?
ChadTower:
--- Quote from: Neverending Project on January 04, 2009, 11:04:46 pm ---I replaced the header pins on both the regulator and the SDU, and the connector on the regulator. I suppose I can replace the connector to the SDU also (it is not brown or burned at all), but if there is extra resistance somewhere, shouldn't changing the variable pot still change the HV at the test point, even if it is low overall?
--- End quote ---
It probably should, yeah, but without looking at the circuit I don't think I can give you a guess as to what would be causing that. Are you sure they're on the same circuit?
StephenH:
This might help you:
http://www.pinrepair.com/bally/index3.htm#display
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