AX 1200i needs some heat to boot PC

My AX1200i will not boot the PC if it is cold, about 10-15°C or below.

It will always get as far as the point where you normally see the amount and speed of RAM but requires heat to get to BIOS or boot. Basically the PSU can power the machine fine but it balks at OS load.

After a failed boot the power supply needs power removed for a few seconds before you can try again.

People will say its a broken track or connection that expands and that is why it works when it is heated.

However the amount of heating required to boot the PC is not enough to provide any significant thermal expansion and is therefore not, in my opinion, a valid conclusion.

I use a small blow heater in the general region of the PSU and it will always boot after about 15 or 20 seconds of this low level of heating. Given the thermal inertia of a heavy power supply like the AX1200i it means the only significant temperature delta is of the air being drawn/ blown into the PSU.

This leads me to the conclusion that there is some temperature sensor or other thermally sensitive component which needs the ambient temperature to be about 20°C or so instead of a normally lower temperature.

I wondered if it could simply be a resistor of the wrong spec in series with any a thermocouple used in these PSUs.

It is an EBAY special and has always exhibited this behaviour and isnt really a problem, and has been powering my various rigs for the last three years without any other issue. I just wondered if anyone has seen a similar problem, have they been able to fix it or if there has been a batch of these PSUs that had gone out with the wrong value of resistor or duff thermocouples something similar.

I am well aware of how dangerous it is to work on exposed power supplys with charged capacitors, but I wondered if anyone has any pictures of suspect components or any maintenance experience with this model ?