First thing I did once I got it home was to set it up so I could see what worked and what didn’t. I left the game set up on my trolley; I couldn’t bolt the legs on as the threads were stripped out on all four-leg bolt mounting plates (each bolt had 3/8” nuts screwed on from inside the cabinet). Once the back box was mounted, I replaced the missing connectors to the power supply and re-pinned the others as needed. Next I checked the voltages from the voltage regulator board, all were correct except for the high voltage for the displays, it was putting out 230 volts suggesting shorted transistors. I didn’t have the necessary parts on hand to repair it so it was left as it was for the moment, while I ordered the parts needed.
During that week I ordered the necessary components to repair the display regulator circuit, I replaced the two 2N3440 transistors, the diodes and caps C27 and C28, and I then was able to adjust the voltage to the correct value.
I powered up the game for the first time and was greeted with horrible noise from the speaker, which disappeared once the MPU had booted up. I put the game into self test mode to check all the hardware, in lamp test only half of the lamps flashed, as expected with possible blown lamps/faulty sockets (I ran the lamp driver board on my test jig later on and it worked flawlessly).
Next was the display test… a few digits out on some of the displays, and one had badly burnt segments due to the regulator being bad. The solenoid/sound test was next… only half of the solenoids worked, some intermittently worked and others energized more than once in the test sequence, suggesting to me faulty solenoid address lines to the solenoid driver. Furthermore if a game was started sometimes the wrong coil was activated when certain switches were hit, e.g., if the ball hit a bumper switch a slingshot fired! I then found that by moving connector J4 on the solenoid driver and activating the switches in question, the correct coil would energize. Re-pinning J4 and repairing a few cracked tracks to the solenoid transistors saw all of the solenoids working correctly. while the solenoid board was out, the main filter cap was replaced and all the mods done as per Clays repair guides (not yet done when these pics were taken).
As for the awful noise at power up, I eventually, with the help of a schematic of the soundboard worked out there was no reset pulse arriving at the soundboard. This board has a mute circuit to stop this noise on power up, which is activated by the MPU reset pulse, and is deactivated by the MPU when the power up tune is played. From following the circuit diagram and tracing signals, I eventually discovered that someone had actually cut the reset wire from the soundboard to MPU connectors! Why they had done this is beyond me. Replacing the wire solved the problem.
I now had the game up and running, apart from a few switch issues, which I decided could wait until I was ready to do the playfield restore. Later that week I removed the MPU and removed the old memory battery, cleaned up the corrosion with a 50/50 solution of white vinegar and water and added a remote battery holder fitted with a diode so I could use dry cell batteries.
