8080 game troubleshooting.

tbbk

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Ok, I got this Hit Me machine (Ramtek 1976) at an auction, it was showing random letters, numbers and symbols on the screen when I got it.

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After adjusting the voltage from 5.5 down to 5.1 it now presents me with this screen here.
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According to the manual that is what it is supposed to do (doesn't go into attract mode until after the first game), but I can't get it to start a game. Coining it up SOMETIMES adds symbols on the right hand side (up to 4, but most of the time it doesn't add past the first symbol), but pressing the start button doesn't do anything, and neither did jumping across the right pins for start directly on the board.

Manual to the game is located here. http://www.arcade-museum.com/manuals-videogames/H/HitMe.pdf

I doubt anyone here (other than maybe Greg) has one of these, but I would love if someone who actually knows about boards could take a look at the manual/schematics and tell me what I should be checking next because I simply have no idea what to do next here (already reseated socketed chips and checked board for damage).
 

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Last edited:
On that 8080 chip (3a)
pin 28=+12
pin 20=+5
pin 11=-5

see what you get there, also try adding at leat 4 credits b 4 U try to start game. Something I seen when skimmed manual
 
Ok, checked the voltages at the test points because the board is in the machine and I was having real trouble trying to check at the processor.

+5 was 5.11
+12 was +11.6

-5 is -17.

So the minus 5 appears to be my problem. There are a couple of big transistors on the board in what I assume to be the power section, should those be my next lead?
 
Ok, checked the voltages at the test points because the board is in the machine and I was having real trouble trying to check at the processor.

+5 was 5.11
+12 was +11.6

-5 is -17.

So the minus 5 appears to be my problem. There are a couple of big transistors on the board in what I assume to be the power section, should those be my next lead?

Yes, should be voltage regulators and usually input is on left side ground in center output on right. If there is additional resistance on the ground that will give higher output.
 
Thanks so much for your help. I'll have to wrap this repair session up for the day and get back to it later.
 
Wait, what cap am I supposed to be noticing? One on the board, the cap you didn't use in nope?
 
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