First post, by jami3rez
My first 486 system so I'm basing pretty much everything I know off LGR videos and Claude conversations. I started on Windows '98 and so this era of parts is something I've learned recently.
I have a motherboard, CPU, RAM and video card installed and it won't POST.
Hardware is -
QDI V4P895GRN/SMT Socket 3 Motherboard - https://theretroweb.com/motherboards/s/qdi-v4p895grn-smt
Intel 486-DX2 66
16mb 72PIN FPM RAM UG8M43202KBT-6
Trident TVGA9000C 16 Bit ISA 512KB VGA Video Graphics Card
Installation looks like this -


- It's connected to a CRT, which just displays black. The 'no signal' screen only comes up when I disconnect the cable. I've tried two VGA cables.
- The mobo is getting power, the keyboard lights flash and I can feel the CPU and some chips on the board are warm.
- I've seen images of the motherboard running before I got it, it should be fine.
- I've tried two PSUs. Caveat, one is an ATX PSU I've connected via a converter kit. The other is an ATX PSU that has been manually rewired to have the correct sockets. Both support the -5V rail.
- I've been through the jumpers twice and have set to the appropriate CPU (Intel DX2), speed (33mhz) and voltage (5V).
I don't have alternative kit to troubleshoot with at the moment, although I do have a VLB graphics card and a different RAM module to test on the way.
I did actually try this with a different motherboard/CPU/RAM combo I got on eBay and had the same issue, so returned it thinking it was dead. Seems maybe something else in my setup isn't working. The only common things between those two builds was the PSU(s) and the video card.
I'm assuming all the 'new' AT PSUs on eBay are dodgy as hell. I'm in the UK and there doesn't seem to be many good options for trying a different PSU.
Is there anything else I should be checking or is a big red flag to anyone who knows better?