In the next two weeks I'm going to purchase WD-40 Contact cleaner to clean all of the slots and CPU sockets (as it's safe to use on plastics and rubbers), a PCI Diagnostic card to see what's going on as the system tries to POST and a Seeit TOP201 Universal Programmer to update the BIOS chip with the latest BIOS and hopefully get rid of BIT Rot of there is any. (The ROM Programmer's annoyingly expensive, but it's a model auto detects the target ROM, so it's pretty nifty!)

POST cards are great to have in general, but I don't think in this situation they are going to detect anything. i.e. the problems happen after it's gone past the basics. POST is over when you see the "POST" screen, any recoverable errors it reports (key stuck, CMOS check) and any non-recoverable is where it sticks and the POST card gives you a clue.

Edit: Okay reread, you have some occasions of not making it to the POST screen? Sorry, I may have confused your "not booting" statements with seeing POST screen and then doing nothing. or having the storage interface problems. So yeah if you are looking at a blank screen, maybe a blinking cursor, then the POST card should say something.

BitWrangler wrote on Today, 14:33:

POST cards are great to have in general, but I don't think in this situation they are going to detect anything. i.e. the problems happen after it's gone past the basics. POST is over when you see the "POST" screen, any recoverable errors it reports (key stuck, CMOS check) and any non-recoverable is where it sticks and the POST card gives you a clue.

Edit: Okay reread, you have some occasions of not making it to the POST screen? Sorry, I may have confused your "not booting" statements with seeing POST screen and then doing nothing. or having the storage interface problems. So yeah if you are looking at a blank screen, maybe a blinking cursor, then the POST card should say something.

When it doesn't BOOT, it doesn't POST.

@necoro on the Silicon Graphics User Group Discord suggested these to me to clean PCI clots:(Dual Side Card Reader Cleaner)