Computer PSU failure - voltages low - damage sustained?

[seanspotatobusiness]

A couple of weeks ago my computer would not boot (the fans all started but the power LED appeared to flicker). I measured some of the PSU (Thermaltake 705w 700 W, now eight years old) voltages and the 12 V output was 10.3 V and the 5 V output was 3.5 V. This is far outside of specification. I bought a new PSU (XFX TS 750 W - more than adequate), however the PC will not boot. I don't have a speaker connected to the motherboard so I have ordered one so I can hopefully get a beep code.

In the mean time I was wondering whether anyone could advise on:

• the probable mode of failure of the PSU (now eight years old; I've opened and inspected it and can't see any obvious damage).
• the possible damage sustained by the other components (I was under the impression that under voltage was not a risk but now I'm not so sure).

At least with the new PSU the power LED isn't flickering but that's the only discernible difference at the moment.

 

[KrisBlueNZ]

At least with the new PSU the power LED isn't flickering but that's the only discernible difference at the moment.

What do you mean exactly? Are you saying that the rail voltages are still wrong with the new power supply?