[June 2021] Some months ago I acquired an ECS 945P-M3 motherboard as part of a faulty desktop computer system.

These boards aren't anything particular special, it's an old LGA775 board and seem prone to a certain issue (as we shall see*), but I do like the purple-coloured PCB.

Issue #1: The initial issue was that the BIOS had reset, losing its settings and its ability to BOOT from the hard drive. It turned out that the default setting for the hard drive was RAID rather than the required AHCI (or IDE). I had to remember this while I was working on the board with the CMOS battery removed.

Issue #2: With AHCI set correctly the motherboard seemed to perform reliably, however it was apparent that there was another issue lurking, or leaking; a few capacitors on the board were showing signs of failing (it seems to me this is a common issue with these boards).

The obviously failing capacitors were all of the same type (1000uF 6.3V 105'c) so I elected to treat this as a project board and replace those ones (rather than interfere with any of the others that looked fine). I'd never "recapped" a board before but had watched Youtube videos of the process involved. I ordered replacement components, although I elected for 'Hitano' ones, but checked they were going to be of a similar size.

Here are the old capacitors removed:

It was fortunate I was treating this as a project board as I managed to cause some damage in the desoldering process; one of the (very) nearby traces got damaged (I'd evidently applied a little too much heat to the board here in my effort to remove the capacitors). Luckily I noticed the problem before testing the board because the fine copper trace was now making contact with the solder pad of the neighbouring capacitor.

Thankfully the trace was still in tact and I was able to gently nudge back to its original location; I then covered it over with a dab of paint.

I powered up the motherboard and it worked (I was quite surprised!). I have done no further testing yet though so I can only assume all the replaced capacitors are doing their thing (one looks to be related to the PCI-E x1 slot).

Issue #3: While I was replacing the capacitors I noticed some further damage to the motherboard. A component had failed near the USB headers and left a sooty mark up the board.

I was already aware that there was damage to the USB sockets on the front of the computer's case, and these headers were where those sockets connected to. I had assumed that the sockets had just been broken at some point and that was the extent of the issue, but now it seemed obvious that in the process of the sockets being damaged a short had damaged whatever component was supposed to be at that location on the board. I tested the headers and indeed found them not to be working.

Due to the extent of the damage there was no component left to determine what exactly should have been there. I looked at other motherboards I had to look for something similar, but with no luck. I also looked for images on Google and for similar motherboards being sold on ebay to see if I could determine what component was there, but sadly none of the images were of a high enough resolution. I also considered buying another of the same motherboard just so I could identify the component and repair this one, but none were available for a reasonable price.

It seemed that whatever component was originally there simply bridged two solder pads, rather than there being, say two or three contacts on one side and one on the other; there were also no similar components elsewhere on the board that I could refer to. It wasn't until I was searching for components for another project that I happened upon an image of a "resettable fuse" and I realised that's what was likely what I needed. But of what value? I still didn't know this but I took another look at my other motherboards and found one with similar components neighbouring the USB headers and found one with a resettable fuse here, I could see the numbers printed on it (P 260) and have ordered some of the same (PTTC SPR-P260T SMD 2.6A 6V PTC Resettable Fuses).

They'll be coming from China so will take a while; hopefully that'll get the USB headers working again. The USB sockets on the front of the case are too damaged to repair and are not easily replaceable so I'll likely fill them with hot glue to seal them off and connect a fresh set of sockets that can be situated in a spare drive bay.

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