Muchi Muchi Pork sometimes not booting

[buffi]

So, I have a strange issue with my MMP pcb.
When I want to play it, it never works when I initially turn on my cab. The status LED just stays lit forever
If I then restart the cab after a while, the game plays fine.

Any idea what could cause this?

[EOJ]

Have you tried it on a different cab or supergun? Does your cab have issues with any other games?

[buffi]

No issues with other CV1000 pcbs on this cab (I have 7 other ones I think).
Good idea on trying it in a supergun though. I’ll try that tonight.

[SuperPang]

Have you measured the 5V under load?

[buffi]

Have you measured the 5V under load?

So... uh, I feel like an idiot now.
I don't think I've ever adjusted my 5V on my Astro City that I've had for 10+ years.
Meassured it and it was at 5.22v while playing the game. That seems way too high.

Brought it down to 5.0V now. Will see if that's enough to make things work reliably. Otherwise I'll dig out my supergun to see if that changes things.

Works fine today at least!

[EOJ]

MMP is known to be particularly sensitive to voltage. I have mine at 5.07v and it works perfectly, but if it goes much higher there can be problems.

[buffi]

So, this is legit weird. Same thing happens on my supergun.
Voltage is now 5.0V.

When I first start the game, nothing happens (LED stays lit). If I leave it on for a while like this, and then restarts it, it works.
If I play it again a short while after turning it off (like 10 minutes seems fine), then it also immediately works.

I wonder if some capacitor or something is going bad? That could _maybe_ explain it, if the cap takes a long time to build up the voltage or something?

Either way, very strange issue.

[rtw]

MMP is not special when it comes to voltage. All CV1K PCBs are the same.
The 5V is transformed into 3V3 and 2V5 which is used by the devices on the PCB.

@buffi, I assume it is the LED at D6 which is not turning off on your PCB when you power it ?