Space Invanders Deluxe and the 90400

MonsterBash

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I'm having a little issue with a 90400 in my SID. The original PS was blowing the 18V (line) fuse on the transformer block so I robbed the PS I just rebuild in hope of getting my SeaWolf up and running.

The robbed PS has a BR cap kit as well as the VR and the the 2n3055 replaced. In the Sea Wolf the PS wouldn't give me a steady 5V...when testing it would walk about .5V from say 5.3 to 5.8

After rebuilding the PS it never made it back to the Seawolf. So now the PS has the exact same problem...

The voltages walk (+5, -5 and +12) about .5V and adjusting the pots have no effect on any of the voltages...basically the pots do nothing. I did ohm out the POTs and they were fine. It make no different if the PCB is installed or not

The SID will sometimes boot...and sometimes not. It seems that if the game is off for a while..say a week...it'll boot fine. If it's switch off and on a couple time day..eventually it just get garage on the screen like the reset circuit kicked in. Probably the only place I have steady voltage is on the reset circuit at .25V.

Any Ideas?
 
I think your original post is a little confusing, but if I get it right...you took a power supply from your Sea Wolf that you had rebuilt, and are trying to use it in your SID?

You should see a blip on the reset line when the game is first turned on (using a logic probe powered up by some other means). If you dont see the blip...the reset line may not be working properly, or its possible the reset circuits on the daughterboard or mainboard may need some attention, or maybe the edge connector between the two isn't making good contact.

Lastly, check the slam switch on the coin door to make sure its not mangled and randomly shorting the reset line.

PS - while it shouldn't "walk" per se, the voltages on these games does fluctuate a little, moreso on Seawolf due to the 11,000 lights it uses.
 
Yeah..I can see the confusion...let me simplify a bit

Original SID PS blows on the 2 AMP fuses next to the transformer. That PS is on the bench

About 3 month ago I rebuilt a PS for my Sea Wolf that I never tested after rebuild.

Before the rebuild the PS walked on the 12v 5v and -5v all walked about .5v when tested at the corresponding test points...had the same results after the rebuild which Included the VR.

I did not replace the POTs but they OHMd out fine. Is it possible that all 3 POTs are bad even though they 'tested' fine?



Does the PS you are using have new pots on it for adjusting the voltage ?
 
I did not replace the POTs but they OHMd out fine. Is it possible that all 3 POTs are bad even though they 'tested' fine?

YES!`

You probably did not test under a load or with any real current going thru them and if you did you probably did not do that for some time to watch for changes.
 
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