Hi folks!
I'm restoring a Blackout I picked up recently from a co-worker. It had been in his basement for years and years, and he originally got it out of someone's basement.. The boards were a little bit of a mix & match- for example the sound/speech board was out of a Gorgar. I swapped in Blackout sound and speech roms, and replaced several TIP120's and the pre-driver transistors too on the driver board- the solenoid drivers that signal the sound board to play sounds. Now sound/speech is fully working. Neat game!
I cleaned the scanbe connectors and ROM/CPU pins, and plugged them back in- just to see if I could get anything running, before attempting de-solder and replacement of the sockets. These chips can be removed by hand with no tools- so clearly they need to be replaced. The 40-pin interconnect was fairly tight, but original. It was cleaned too (de-oxit).. I've not replaced any capacitors either in the power supply. Believe it or not, the game was fully working for a few days (albeit with a lamp row out, lamp column out, and the above mentioned sound board issues.) I had to wait a few days for the parts to come in- but after desolder and resolder of the suspect driver transistors, the lamps all work. I actually replaced these lamp drivers first, and the game was fine/stable. Then I replaced the sound transistors..
So: Here's my issue: After replacing the sound driver transistors on the driver board (basically the bottom left 4), the game would not boot at all. I somehow figured out, that with the coin door open, auto-up/manual switch to up, and power the game on, the displays light, the credits appear to be rapidly counting up. If you look at the CPU board when you do this, both LEDs flash once and then go off, then both flash twice, and go off.... Every now and then, if you go away and then come back in a few minutes, and power up, the game is normal, and can be played.. Sounds, all lights, all solenoids, all switches working fine. Then, it will lock up mid game- and go back to the above mentioned behavior.
I am thinking perhaps I need to replace the 5 volt smoothing cap in the power supply? I've had system 80 Gottliebs that behaved sort of like this when the big orange cap in the cabinet was bad... I know I need to change out the interconnect, all p/s caps, and the scanbe sockets for good practice- but I also don't like to change too many things all at once.
Ideas?
Jason