I've looked in the Gameplan guide thread and can't find the issue I'm having. It's not a huge deal as it's been this way for almost 2 years now, but would like to get it fixed. There is absolutely no battery damage. Super clean board running a 1.5F supercap. The game is Cyclopes if that matters.

Here's the issue:

Game off. Turn game on with switch and most times (7/10) just the GI lights come on and then nothing. Turn off and back on and game boots up and plays fine. Sometimes (1/10) you might have to turn off and on again for a second time. When it boots up it plays fine, no issues whatsoever.

I do get all 6 flashes on the MPU when it does boot. When it doesn't boot. Nothing. I do notice that when I turn the game on and I don't get a quick flicker (usually of a 5) in the 10s score display it's not going to boot. If I turn it on and see the 5 flicker in the 10s digit of the display, I'm golden.

If the game turns on the first try, after it's been on and played previously, it retains the previous game scores. If it doesn't boot on the first try you get garbage numbers. Typically like 910910 in all 4 positions, and the high score to date is like 9910300.

I've replaced the boot up section transistors, Z80 and PIA thinking that was the issue and no change. Now I'm thinking it might be the 6810 RAM, because it displays garbage when it does boot up. But I would think it would only do a partial boot up sequence because it checks the RAM in order to pass the 3rd flash.

Any ideas what the issue(s) may be? It's either nothing or full boot at power up. When it boots it plays perfectly fine.

I've rebuilt the power supply when I first got it, yes. It had this issue before then too.

One other thing to point to something on the MPU as the culprit. I had an Echo Lake MPU installed at one point and it booted 100% of the time, every time. So I know it's something on the MPU.

The Echo Lake board had it's own unique issue in that it won't work properly in a Cyclopes. The Echo Lake board has a switch handling problem and it causes the game not to play properly. Jim could not figure out the issue so I sold the board.

Finally found some time and decided to tackle this problem. Basically a sporadic non-boot issue with my Cyclopes running the original MPU-2 board.

Ended up being a bad 74LS04 hex inverter at U3 that would cause the game to sometimes not boot on the first try. When testing the 5V on pin 26 of U11, when the game would not boot, that voltage would be very rapidly changing from 0 to 5V. If the game booted properly, the voltage at pin 26 on U11 was a solid 5V.