No-Post scenario....ALL parts replaced??

Ross Siggers · November 14, 2022

Hi all, I'm completely stumped and need more suggestions for advanced troubleshooting! The PC is a small form factor build, so there are a few differences to a regular build, outlined below. It's been a complete and running system for near 2 years now, but I should clarify these because the internal layout is unorthodox.

The motherboard is an STX format, smaller than ITX but similar to a 'thin' client that takes direct 19v via a barrel connector.
It uses a Pico PSU. So an external brick, and inside the case power is split. One feed goes to the pico for ssd/gpu. And one to the motherboard.
Gpu is run off an m.2 slot via a riser cable.

THE ISSUE

I was upgrading the ram on the PC from 8gb to 16gb. When I reassembled it could only post sporadically. I could get into windows a few times, but eventually it failed to boot on all attempts. The troubleshooting so far as follows:

Changed ram back to the original kit.
Bought another CPU and ran the system with that instead.
Unplugged the GPU from its riser and used the motherboard video-out.
Disconnected the ssd.
Replaced the motherboard with a brand new STX.
Since all ancillaries were now removed, I bypassed the PSU and fed the motherboard directly.
Related to the above, I tried x3 different power bricks to rule that out as well.
Used my spare components to build a second system... that won't post either.
checked cables

As you can see...literally every single component has either been disconnected, or replaced. I'm.... completely and utterly lost. I now have two systems neither of which will reach post. I've reached the limit of my troubleshooting expertise, so I'm putting this issue out to the wider community. Y'all...wtf us going on?!?!

Robchil · November 14, 2022

have you tried to test everything outside the case?

btw.. i have had cases where one component destroys other components that destroys new components it's connected to.

Ross Siggers · November 14, 2022

1 hour ago, Robchil said:

have you tried to test everything outside the case?

btw.. i have had cases where one component destroys other components that destroys new components it's connected to.

I mean, the case is plastic so I don't think it's a short or anything like that. But yes, by the time I'd reached the 'two systems' stage, I was just bench testing everything.

Tell me more about this destructive component scenario though... what part of the build was it? I did wonder if the PSU was doing something as it was used initially to boot the new motherboard, it's a 200W Pico but the biggest power brick I've tested with is only 120W. So even though it's not being stressed that could be the case, if I was exceptionally unlucky.

Robchil · November 14, 2022

i've seen CPU's destroy mainboard and ram, ram destroy CPU's. mainboard destroy GPU's and GPU's take out mainboards... also seen PSU's take out mainboards CPU's and GPU's.

start from scratch with what worked... outside the case.

Ross Siggers · January 12, 2023

On 11/14/2022 at 7:37 PM, Robchil said:

Start from scratch with what worked... outside the case.

I mean, that's the problem, the original configuration doesn't work. I've mixed and matched components between the two systems and it doesn't seem like any combination works.

I tried plugging in a mouse with lights on it and they flash on when you power the PC....but then quickly go off, and the machine stays in the same state; powered on, fans ramped up, no display output.

Also saw something about a POST self test cards that give you a display for codes, and a speaker for error beeps....does anyone know if that would even work on this machine? As those test cards run off a PCI slot, and I currently have the PCIe for the GPU, running over an M.2 slot. Would be great if it did work, so I could at least see if it's throwing codes.