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Hi all,

I've not been able to get any signal from the VGA on my RaspberryJamma.

Without a power light, is there a way to test if it's working correctly?

I need to diagnose if I have a hardware or software issue.

Thank you!

The LEDs on the Rpi5 can help diagnose the issue.  Trying the board outside the cab, even just using the RPi power suply and HDMI out if you don't have another VGA monitor could help determine if there's a hardware issue (or maybe help figure it out otherwise).

Unsure if you got the email reply from me a couple of days ago so I'll also copy that in: (rest is copied from my email reply)

sorry you're having issues with it, no need to apologize for reaching out.  I'll do whatever I can to help.  I'm assuming you're 'mysterious' on the forum, let me know if that's not you and its just a weird coincidence...

Pi5 can be a bit tricky to run off an arcade power supply, depending on your arcade power supply (if it's old/out of spec and takes a little long to get up to voltage the Pi5 won't like it).  A couple of people have resorted to powering the Pi5 via a Pi power supply and disconnecting the JAMMA 5v, mostly though that should not be necessary but is available as a last resort (see this thread for more on this: https://www.arpicade.net/index.php/topic,97.0.html ).  One user reported having a very small range on the arcade power supply 5v adjust where it all worked. 

The LEDs on the Pi can help figure out what the issue is.  When there's a problem they can blink diagnostic codes to help figure it out, if there's any blinking LED action please describe it for me (it'l flash in short and long pulse combinations).

Is the 'red light and crash' when ran in the JAMMA cab just a red LED and no action at all?  If so it isn't starting up and the first thing I'd try is to press the tiny button on the side of the Pi5 (near the SD card), if your cab power is a little low or the power supply ramps up the 5v slowly it might start after a button press (if it starts after a button press we know the issue and can try to fix that).  You could also test with the JAMMA connector removed and just use the VGA output (you will need to use the Pi power supply with the JAMMA edge removed, normally you'd be getting JAMMA power and you don't ever want both JAMMA power and Pi power supply at the same time unless you remove the fuse from the RaspberryJAMMA), similarly if it runs on the Pi power supply and successfully outputs VGA we know the issue is related to the cabs power supply and can work on it.

If it is partially booting (if there's a bit of green LED action to go with the red) and crashing it may be your 5v is just a bit low in the cab.  Pi5 likes 5.1v not 5v so if you swapped out the JAMMA board without any adjustment to the JAMMA power supply that could be all it needs.  If you need to adjust the JAMMA 5v be careful, use a multi meter to measure it at the JAMMA edge with the board attached so you don't accidentally go to far.  You will likely need a little over 5.1v to account for voltage drop on the JAMMA board prior to the Pi, don't go over 5.25v as it could damage the Pi and that high isn't needed.

What's your JAMMA harness like?  Does it have many wires going to the 5v on the power supply or just 1?  If you only have one wire for 5v that could be the cause of the issue, cheapy JAMMA looms are often not good enough for much more than a 60in1 without upgrading the power wires as they use one thin aluminium wire with thick plastic insulation for each power connection.  80s and 90s harness' have nice thicker gauge copper wire usually at least 2 wires for each connection too, often they have four 5v and four (or more) gnd wires.

Off the power and onto the 480p, when you run it into the HDMI monitor/TV does it report the resolution at all (you may need to press the info button if it doesn't show up automatically).  It's likely on a VGA monitor if it is stuck in low res the monitor won't show any picture, however it sounded like you had already set the software to high res in the forum post...

Hopefully something in there helps, please let me know how you go with the couple of things I've suggested testing as they may lead to further suggestions.  Ask more questions if you need, I'm here to help.  In the thread you started I was assuming it was a software issue but at the moment I'm leaning to it being power related, although I'm not certain on that either...