An idiot in need of help with Space invaders

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Hi!

This is my first post to this forum, and an embarrasing one too.
I recently bought a Space invaders upright that was partially working.. Monitor and gameboard seemed ok and was playable but sounds was missing. allso backlite and bezel lights was out. I opened the back and had a peak inside..even before i looked at the users manual.. i saw this PCB mounted on the left side having some pots on it (later found out to be the Power Circuit)...
And to the ebarrasing part: I started to turn on those pots causing the game to totally blank out..and now all that there is is a white dot at the center of the screen and no sign of life at all.. at first there was some white bars on the screen then all that was left was the little white dot. God I'm such idiot!!! I have only 'experience' with never Jamma cabinets and i'm used to pots just being for adjusting volume and horiz/vertical scroll and so on...

I consulted this page for som help: http://www.elektronforge.com/TestMdwPS.htm
And after measuring i found that even on the lowest settings the pots regulating +5 +12 and -5 volts all was 3-4 volts too high..

So it seems like it was to high allready but i obviously have done it much worse since nothing works anymore..

Have i killed it?? I wonder if i could have damaged the monitor? or just the Game boards.
have i burned the whole game?

Thankyou for your time. And appologize for being such a DUMBA**!
I have learned my lesson from now to NEVER touch anything unless i know what i'm doing..
And right now i feel i know nothing..
 
Re:

I have done worse things. You need a multimeter to test and adjust the voltages. That's what I like about this hobby, because you learn something new every day, even if you learn it the hard way!
 
And to the ebarrasing part: I started to turn on those pots causing the game to totally blank out..and now all that there is is a white dot at the center of the screen and no sign of life at all.. at first there was some white bars on the screen then all that was left was the little white dot. God I'm such idiot!!! I have only 'experience' with never Jamma cabinets and i'm used to pots just being for adjusting volume and horiz/vertical scroll and so on...

I consulted this page for som help: http://www.elektronforge.com/TestMdwPS.htm
And after measuring i found that even on the lowest settings the pots regulating +5 +12 and -5 volts all was 3-4 volts too high..

Are you sure you're measuring those voltages correctly? I ask because the 5VDC line and the 12VDC line are fed from two separate taps off the transformer...thus two separate circuits. It would be unusual for two separate circuits to crap out at the same time.

If all voltages are 3-4 volts too high....something's up with the power supply board (and unlikely, but not impossible...the transformer). You need to start at the begunning of the circuits and work your way out. Do this with the motherboard unplugged. Fix the power supply first.

As for as a "dot" in the center of the screen....that really sounds like a monitor problem.

Edward
 
Thankyou guys! all of you. Help is much appreciated. :)

Superbee: Thanks:)

FlavaDave: The hard way works!:p

EMmetoo: Didnt really contact them, just followed their online metering instructions.


If all voltages are 3-4 volts too high....something's up with the power supply board (and unlikely, but not impossible...the transformer). You need to start at the begunning of the circuits and work your way out. Do this with the motherboard unplugged. Fix the power supply first.

As for as a "dot" in the center of the screen....that really sounds like a monitor problem.

Yes i will start from there, change the pots and the caps. Since the monitor worked just fine before i started fingering with the pots, is it possible that i ruined it? not sure if the monitor gets any power from the power circuit board.. but if it does i probably messed it up i guess

But again thanks!:)
Now i know where to start..

Kurt
 
Last edited:
Thankyou guys! all of you. Help is much appreciated. :D

Superbee: Thanks:)

FlavaDave: The hard way works!:p

EMmetoo: Didnt really contact them, just followed their online metering instructions.




Yes i will start from there, change the pots and the caps. Since the monitor worked just fine before i started fingering with the pots, is it possible that i ruined it? not sure if the monitor gets any power from the power circuit board.. but if it does i probably messed it up i guess

But again thanks!:D
Now i know where to start..

Kurt

The monitor's power comes straight from the power cord. The power supply board is only for the motherboard.

Edward
 
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