Resolved Optiplex GX270 technical issues

Hi! Today I picked up a bunch of computer parts and two computers for free. One of these is clearly very dead and I have no intention of resurrecting, but the Dell Optiplex GX270 I picked up seems saveable. In fact, it was working perfectly until I tried a different IDE cable inside... ever since, it's simply left with an orange power light and absolutely no response from the power button.

I have disconnected and reconnected the essential cables, and no non-essential device is currently connected, yet the issue remains. There are no blown, or even visibly swollen capacitors inside, and it had previously booted up Windows on a hard drive (which I removed due to it containing personal information of someone else's). The power supply fan is not moving, but the CPU fan is (at a regular speed, not at high speed).

Could this indicate a PSU failure or some other PSU issue? And where can I find the correct caddy/rails for a GX270 to accept a hard drive? Are there any size requirements for a hard drive inside a GX270?

 

Are both PCs the same model?

Did you try using the PSU from the other PC to see if it would fire up?

 

The computers are completely dissimilar. I'm not entirely sure that my other PSUs match the main "ATX" connector on the Optiplex GX270, as I know Dell have custom-built their connectors on some older machinery - is it a standard 20 pin connector or is it proprietary?

 

Did you try putting the original HD back in and see what happens?

 

I don't have an original hard drive for the computer (it was just a random one from the lot of parts I picked up). And it's stuck before it even gets to BIOS - no POST, no attempt to load BIOS, just an orange light on solidly.

 

Right. Can anyone tell me if the PSU connector on the machine is a standard 20 pin ATX one, or if Dell made it proprietary (so I can test the machine with a different PSU)?

 

It did indeed look similar, I'll pull the 300W unit in my existing P4 machine and test it with that later.

 

Well, it does look like the PSU was quite probably at fault, but the motherboard also appears to be dodgy - I found a bag of bits I'd missed, and there was another PSU inside. This does not squeal and the fan operates correctly (and very quietly), so I believe it to be good - but the orange light remains. Guess I'll be ordering a replacement motherboard from eBay then!

 

I'm not entirely sure what has failed on the motherboard, as all the capacitors are good (and they're Rubicons, so it's either been recalled and replaced, or it's a later model board) and there are no obvious burn marks. That said, the chipset heatsink does get warm to the touch very quickly, if not excessively hot.

 

Just an update - I've ordered a replacement motherboard for the machine. Having disassembled the previous power supply and attempted to rotate the fan, it was almost totally seized - I could spin it, but it would require a bit of effort and it would simply stop turning the moment I removed my own force from it.

 

The computer now runs fine - the new motherboard is perfect and it was indeed a motherboard fault, as the CPU is now happily working in my other Pentium 4 machine.

However, there appears to be an issue with the optical drive cable, which allows the laptop-style drives to power perfectly but does not seem to send any data to the motherboard. Both IDE ports are tested as being good (by myself), so that's not the issue, and I tested it with both Optiplex optical drives I have, but there are no visible fractures in the cable. That said, I will be ordering a replacement cable sooner or later.

Just an update