So this machine was bought as a non working project machine. The prievous owner of the machine bought a bob Roberts power supply cap kit and installed it. He bought several sound boards. I tangled with this machine and was able to get it to play one level and it would reboot. Might be a rom issue. The voltages seem to be ok. The prievous owner bought a glass bezzle for it. Looks great but doesn't work. It was put on the project pile to be worked on later. Well like some projects, it was move to a new owner. Which is cool because, It is in a location where I can get to it and spend time and effort into it to bring it back to life.
So the first thing that was tried was a new set of EPROMs. It made it worse. Bars across the screen. Bad EPROM burn. Read the old EPROMs and figured out their locations. The machine still reboot after one level is played but at least it is better.
I need to isolate the problem. Power supply or board. I opened a space invaders cab and borrowed it's power supply. The deluxe still acting the same. I wasn't worried about doing damage to the old power supply because the deluxe was just rebooting.
There was no sound on the game it was rebooting after one level. I take a closer look at this board. Odd caps are missing off this board. I think this board was in some one's junk pile.
So I install a cap and the machine throws garbage on the screen. It does not like caps and it crashes when you install one. Remove the cap and the board returns to the old one screen game play crash state.
I do not have my scope with me or the schematics. Welcome to another rocks and stick repair lol. I do have a Dvm and a logic probe. Probed around withe the logic probe the 556 is shorted it was replaced it. It now plays to the second level.
Still has the install a cap crash problem. Blown 3900 maybe? add a cap and the blown chip might cause the board to crash. So I replace one lm3900 chip k5. I got a little sound and its not throwing garbage on the screen. Install another lm3900 chip M5. Installed missing cap.
Garbage on the screen happens again. Remove cap and the game comes up. Ok something is dragging the power supply down and causing the board to crash.
Time to thro a esr meter in. So I look at the caps around m5. They all seem to be working. Odd. I probe the Caps near the edge connector. Bingo found a shorted out cap. Replaced. Tested the board. Ok still working with new cap installed. Installed the cap for m5. I got more sounds and no garage screen issues.
Start to install the rest of the caps. That we're missing and all he sounds start to come back. The gem plays great but there no sounds when you shoot the laser. Another pair of lm3900 again P4 M4 and there is sounds.
I put the new power supply in. 12 volts is not adjusting so I replaced both 7905 - 5 volt regulator and the 7812. Power supply is now adjustable.
The game now works and ready to be played once again.
Thanks to the previous owner who bought extra sound boards. I used one to compare caps with the esr meter and used one board for source of caps. New owner will need to buy more caps to fix the other board.
Thanks to the new owner. For having an esr meter and a stock of 14 pin sockets and lm3900 stock on hand. You will need to buy more caps to replace the ones I borrowed off the dead sound board. You need to buy 7905 and 7812 regulators just to have on hand.
Having some caps removed from the board was a blessing. It allowed a crippled board to come up. I will post a picture later on where this caps were locate in perhaps someday it will help another person to repair their game.
Another 3 am repair. Lol
So the first thing that was tried was a new set of EPROMs. It made it worse. Bars across the screen. Bad EPROM burn. Read the old EPROMs and figured out their locations. The machine still reboot after one level is played but at least it is better.
I need to isolate the problem. Power supply or board. I opened a space invaders cab and borrowed it's power supply. The deluxe still acting the same. I wasn't worried about doing damage to the old power supply because the deluxe was just rebooting.
There was no sound on the game it was rebooting after one level. I take a closer look at this board. Odd caps are missing off this board. I think this board was in some one's junk pile.
So I install a cap and the machine throws garbage on the screen. It does not like caps and it crashes when you install one. Remove the cap and the board returns to the old one screen game play crash state.
I do not have my scope with me or the schematics. Welcome to another rocks and stick repair lol. I do have a Dvm and a logic probe. Probed around withe the logic probe the 556 is shorted it was replaced it. It now plays to the second level.
Still has the install a cap crash problem. Blown 3900 maybe? add a cap and the blown chip might cause the board to crash. So I replace one lm3900 chip k5. I got a little sound and its not throwing garbage on the screen. Install another lm3900 chip M5. Installed missing cap.
Garbage on the screen happens again. Remove cap and the game comes up. Ok something is dragging the power supply down and causing the board to crash.
Time to thro a esr meter in. So I look at the caps around m5. They all seem to be working. Odd. I probe the Caps near the edge connector. Bingo found a shorted out cap. Replaced. Tested the board. Ok still working with new cap installed. Installed the cap for m5. I got more sounds and no garage screen issues.
Start to install the rest of the caps. That we're missing and all he sounds start to come back. The gem plays great but there no sounds when you shoot the laser. Another pair of lm3900 again P4 M4 and there is sounds.
I put the new power supply in. 12 volts is not adjusting so I replaced both 7905 - 5 volt regulator and the 7812. Power supply is now adjustable.
The game now works and ready to be played once again.
Thanks to the previous owner who bought extra sound boards. I used one to compare caps with the esr meter and used one board for source of caps. New owner will need to buy more caps to fix the other board.
Thanks to the new owner. For having an esr meter and a stock of 14 pin sockets and lm3900 stock on hand. You will need to buy more caps to replace the ones I borrowed off the dead sound board. You need to buy 7905 and 7812 regulators just to have on hand.
Having some caps removed from the board was a blessing. It allowed a crippled board to come up. I will post a picture later on where this caps were locate in perhaps someday it will help another person to repair their game.
Another 3 am repair. Lol