Need some advice please. When the game has been off for a while, and I turn it on and it completes the boot, the start switch doesn't do anything. Then, if the game sits on for a minute or so, the switch begins to work. If I turn the game off for a minute and turn it back on, the switch works. So sees to be that something needs to be warm before the switch works.

i have replaced the switch. No change.

When I go into switch test, the switch doesn't register until the machine warms up. Any ideas?

I have done that and there is no corrosion.

The start button tests good. I checked the continuity when pressing it and it is good. I had another switch and went ahead and changed it anyway. Made no difference.

Should jumpering on the MPU J207-1 to J209-3 start a game?

I don’t see any corrosion.

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Well, for the past day, the start button has been working....however: thank you Roamin for the detailed information. Even though it is working now, something isn't right. I'll start first by saying this problem began after installing the color DMD mod. Second, even though the start button is working starting a game, when I jumper MPU J207-1 to J209-3, it doesn't start a game. It fires a solenoid under the playfield (haven't determined which one). Lastly, that board you see at J210 was there when I got the game. I don't know anything about it.

So does it sound like I have a weak 12v power supply?

Also, are all these optos supposed to show illuminated in this test? They work fine playing a game. The switch tests show no faults otherwise.

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I measured the 5 and 12 volt points at the MPU J210 and on the driver board TP2 and TP3. On the MPU I get 4.8v and 11.8v. On the driver board I get 4.86 at TP2 and 11.96 at TP3. Are these too low? If so, which components would need to be replaced?

I checked the connector at J101. It is clean. I reseated it and made no difference.

C2 also does not appear to have leaked (externally). I can replace if you think it looks suspect.

Go do the piniwiki upgrades next?

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Still wondering if all these optos showing closed is normal:

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Thank you for confirming that! So I guess my first task will be to get the 5v and 12v higher. I'll start on that next.

Checked all the caps on the driver board. C4 on the 5v supply measured 48uF. Supposed to be 100uF. I've ordered caps and will replace them all for another 20-30 years of service life. I should have good 5v supply soon and will report back.

Replaced all the electrolytic caps on the driver board. Measuring the 5 and 12 volt TP's now I have 4.9v and 12.0v. I removed the Kahr board too. Game is playing fine. Are these voltages ok now, and should I leave the Kahr board out?