Space Invaders Repair Help???

FlashbackArcade

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I just picked up a Space Invaders machine that is not working and I would like some insight as to what might be wrong with the machine. Upon turning the machine on, I get a loud hum from the machine and the never starts. There are no sounds and pressing all buttons makes no difference. I have attached a few pics to show how the screen looks when the machine is turned on. I would greatly appreciate any help in fixing this problem.

Thanks,

Mike
 
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1. Check for +5 vdc at the motherboard ( if you have a meter and can use it).
2. Re-seat all socketed chips on the motherboard and separate the motherboard from the daughter board and clean the edge connector with an eraser or even some rubbing alcohol.

That would be the first two things I would do. If that is not something you feel comfortable with then you need to get someone over to your house to work on it for you.
 
Sort of looks like just the random pattern that memory powers up in before the
CPU has even had a chance to run which could mean all sorts of things, so like
Arc said, start with the basics first. You do have (some) power else you would
not have the garbage display in pic #2. The power supply provides a reset line to
the game and if that is not working the game (CPU) usually stays stuck held in reset.
If the CPU is bad/dirty game will also not run. if ROMs are bad game may not
run, but sometimes you see a tiny bit of life, same with bad rams, sometimes you
see a tiny bit of life. The clocking circuits are working as it is displaying video.
Anytime the game does not run you are left with a display that is just the garbage
random patter that the drams powerup with.
 
actually, the first thing I would do is buy a Braze kit :)

Seriously, doesn't the kit have some diagnostics in it ? I have one but have not had to mess with it in so long I forget.
 
actually, the first thing I would do is buy a Braze kit :)

Seriously, doesn't the kit have some diagnostics in it ? I have one but have not had to mess with it in so long I forget.

It does have alot of diags I wrote years ago, but off the top of my head, an extensive
ram test without aliasing issues and various hold times, bit shifter test, input test,
interactive sound test menu, etc.

It is a great tool for diagnosing boards because it bypasses all the ROMs and
does a complete RAM test. Most of the time if you have video like he does and
you can get the board to reset properly the kit will run and show life. If it
was a ROM problem since it bypasses the roms it can actually fix a board in
that case, aka "rom saver".

I would first try the basic things, reseat the cpu, clean connectors, etc and see
if it gets any further.
 
Space Invaders Help

Thanks for all of the advice. I have correct voltage at the board, reseated the cpu chips, and cleaned the connections prior to posting my first thread. I sent the boardset out today to be repaired. I am going to order the multiset as well look really cool. Any feedback on how it works and if there are any drawbacks to installing it in my machine? would love to hear more about it if anyone has it.

Mike
 
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