Rather than make a thread for every thing I need to ask, I assume it would be preferred to keep it in one. If not, I'm happy to break into multiple threads.
A friend of mine picked up a James Bond 007 machine, and asked me to get it working so that she could give it to her husband as a birthday present. It's in pretty rough shape cosmetically (back glass is super crazed, playfield paint is cracked and some missing), but so far the actual workings don't seem terrible. My job is to make it function, not to make it look pretty, so no problem.
I've been reading the System 80 tutorials and following a lot of the advice there. So far I've swapped out the orange cap for a 10000uF 25V of slightly younger vintage, and plan to upgrade to a known new one in the near future. The AC ripple dropped from 400+ mV to 200mV, so it's definitely better. I've also added the additional grounds that connect the CPU, driver, and power supply boards to each other and the main ground bus.
It has been powered up and tested, and I think the majority of what needs fixed is adjustments to switch contacts and fixing flaky light bulb sockets. There are a few things I've come across that have raised questions though.
1. The 2A slow-blow fuse that powers the 3 banks of drop targets consistently pops. I've narrowed it down to the bigger solenoid that resets the 5 target bank, as the fuse survives the solenoid test with this one disconnected. The diode on the coil tests out fine, and the coil itself measures a little over 3 ohms, which is in spec. If I run the solenoid test with this one connected, I see it start to move before the fuse blows, and if I drive the coil with a power supply, the solenoid works. Any idea what is causing it to draw too much current?
2. The speaker in the bottom of the cabinet isn't hooked up to anything, and I don't see loose wires that should be connected to it. Does this just get wired in parallel with the one in the top of the cabinet? I have the schematic, but it isn't entirely clear on that.
3. One of the score VFDs isn't working. I can see an extremely faint, almost imperceptible outline of the 000000 shown when the machine powers on, and very occasionally a few segments will flicker on for a split second, but that's it. I've tried it in a different position, and the problem follows the board regardless of which connector it is plugged into. The other 4 work fine, though one is slightly dimmer than the others. I've re-soldered the connections on the back of the bad board, and the contacts look pretty good. What should I try next before giving up and getting a replacement?
4. When I run the chip test diagnostic (#20), I get a 5101 in the P1 score area, but after a few seconds it clears and I get a 99 in the status window. Is this due to a bad battery, or should I replace the 5101? The battery is not the original, but it is an older 3.6V NiCd cell. I plan to replace it next and see if this error clears entirely, but I remember reading that the machine should work without a battery, it just won't retain scores.
5. I haven't added the extra ground and power wires to the CPU/Driver harness because I don't think the pins are available anymore. Is there a modern replacement that will work?
I'm sure I'll have more questions soon enough as I dig in deeper. The deadline for fixing everything is mid-June, and I'm trying to get it done sooner so I have a few weeks to play with... I mean test it, before delivering. It's been a fun project so far!
Thanks in advance for the help!