sut wrote:Just went to power up my ST and after an initial 'flash' no power at all. I've tried with a different power lead still no pulse.
What's this likely to be ?
Dead / No Life? A power supply problem. The power supplies in these are removable modules so there's absolutely no reason to discard the whole machine, and you have various options besides trying to fix the PSUs you have, but let's take a look anyway.
Trying another mains lead was a good start. Next thing is to take the machine apart and look at the PSU - with the power lead disconnected entirely from the machine - and look at the PCB of the PSU. There is usually a glass fuse in a clip-in holder on the PSU PCB. Is that fuse OK?
If it's blown, your options are to
-(Less technical). Replace it with the exact same type, turn on the machine and see if it stays on. Only do this once. If it blows again, don't replace the fuse again as there is a fault somewhere on the PSU. You'll have to fix it or replace it.
-(More technical). Have a look around anything likely to have caused the fuse to blow first. Besides the fuse, does anything else show obvious visual signs of distress (black soot marks, vapourised copper deposits?) Be aware that under certain fault conditions the high voltage capacitors may store a charge for quite some time after the mains input has been removed. It won't kill you but you won't forget it in a hurry. If there's no obvious problem, replace the fuse, but again only once, as above.
If the above is out of your comfort zone, user exxos
here on this forum offers various options from refurb / repair kits for existing ST power supplies, ST power supplies which have already been refurbed, and (just in) an entirely new 21st century design high-spec replacement power supply for the ST range.
You used the word 'flash but you weren't very specific about that. A Flash on the display screen? A flash from inside the unit near the power switch?