Space Invaders Pin Display Problem

jeff412

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Just picked up an SI. I finally got it up and running, but you can see the displays strobing. What controls the strobe speed for the displays?

Jeff
 
I'd start with measuring the voltage to the displays. If that seems to be alright, I'd replace all of the connectors in the harness that feeds the power to the displays.

I had strobing displays on my Black Hole. Turned out the voltage to them was half of what it should have been. Fixed the issue on my power supply board and they're bright again.

Tom
 
Two things:

Bad solder joints on the header connector pins on the displays.

Bad high voltage filter capacitor on the solenoid driver board.
 
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Just picked up an SI. I finally got it up and running, but you can see the displays strobing. What controls the strobe speed for the displays?

Jeff

The display interrupt circuit on the MPU controls the speed at which the displays are updated but that wouldn't be the first thing I check.

It really depends on how fast they're strobing.
 
I'll check the voltage tonight. As far as brightness goes it looks bright enough, I can just see it strobing. When I got it, the filter cap was missing. I found it in the bottom of the cabinet. The legs weren't broken, looks like it just fell out. Of course the wire ties were missing. Could have been the previous Op's fix. It could just be bad solder joints, because I also found a resister that had one leg pulled loose from the board. It wasn't broken either. It just looks like the solder let go.

Jeff
 
It was the voltage. Even though I had adjusted the trim pot before just by looking at the displays. As soon as I put the meter on the test point and adjusted to 170 volts, everything looks great. maybe it was just a dirty pot. Now my ball counter is missing one segment. I guess I'll work on that tonight. Thanks for the help guys.


Jeff
 
Turns out that all of my problems were caused by bad connectors on the solenoid driver board and on the rectifier board.

Jeff
 
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