No Signals

[retrofixer]

Hi everyone,
i have a problem with the cx16, it gives no signs of life.
When I first powered it up, powered with a 20pin ATX power supply only the yellow led was on and it turned off after about 3-4 seconds.
I switched the board back on and it stayed on but with no VGA video signal and no activity on the SD card.
After turning everything off and testing the monitor (but that was working) I tried turning the card back on but it gives no signal, the power supply doesn't turn on and LEDs all off.
Tried another ATX 24pin, same result, got a pico PSU but it won't turn on with that either.
I tested the PSUs on a PC board and they all work.
I'd like to fix the board without having to send it back, sending it back to Texas is not around the corner and there's also customs. Unfortunately, not having schematics and with the 4 layer pcb it's not easy to see where the signals go and if they are OK.
It would seem that the micro-controller is not starting the power supply, I saw a relay on the board, perhaps used for this purpose.
Are there any tests I can do? Check if a voltage is present on a pin chip or some connections etc.?
Thanks

[Stefan]

Check this out and maybe ask Wav for guidance

https://discord.com/channels/5475596260 ... 6815769600

[retrofixer]

Thanks, I checked and the problem seems to be the Attiny..
I reprogrammed it but when I turn it on sometimes it turns off by itself and then unprograms itself
I think it's faulty, I'll try to replace it.

[Stefan]

Can you check the fuse settings of the tiny. Brown-out detection must be set to prevent flash corruption

[retrofixer]

This is my fuse settings:

[Stefan]

Looks alright to me

[retrofixer]

Finally solved!
The first problem was an ATX power supply (which works properly with motherboards) which with this board causes it to shut down shortly after and causes the micro to unprogram.. very strange.
After reprogramming the Attiny several times I found that with the pico ATX the relay doesn't activate or is barely audible, after 3-4 seconds the board shuts down and everything gets stuck, I have to remove power from the pico and try again.
The only way it has worked for me is with another ATX power supply, with this one it turns on and stays on.
Tested with SD and loaded several programs, all ok.
I was planning to put everything inside the Lazer3D case but I have to use a small power supply by necessity.
I will try to change this pico ATX got from Amazon, unfortunately when I ordered the board I didn't buy it.