Let me start by saying thanks for all the help I've had in the past!! A friend of mines Tiny computer got zapped by lightning, and ceased to function. I had a look at it for him and the first thing I noted was the lead for the power switch was severed. I repaired that with a block connector, (as trying to find a replacement lead is like trying to find the proverbial needle!) Hey presto now it works but only occaisionally. The problem is it sometimes wont initiate the monitor, and there is no "beep" . I believe it has IBM BIOS which no beep could indicate a short circuit. Any suggestions would be gratefully appreciated
you will be looking for the proverbial needle to solve this one. Any one of the components could be damaged. I suspect though, as jazzypop suggests that you start with the psu. It is more likely that there is an intermittent fault with this than a motherboard component, "chips" or ic's are so sensitive that if current had got to them they are likely to have been fried and the computer would not have worked at all, but although unlikely this is still possible. Happy hunting!
If that amount of current went through the mobo, I would suspect that a lead from the PSU has had its internal insulation damaged, and two conductors are shorting - but that really is pure speculation.
Far better to start at one end, and work your way through methodically. Slow, but sure :)
Do check out all of the basic circuits and leads first, before you start substititing in known good components. If there is a damaged cable (possibly within the PSU itself), you risk damaging the 'good' component.
I would be inclined to see if a claim can be made under the household insurance for a replacement PC :)
If the monitor draws its power from the PC case, it *could* do - but so could many other things.
I'm sorry, but it is pretty fruitless trying to speculate and dive in on the most likely cause. From experience of many, many similar situations, I can honestly say that the fastest way to fix it is to start at one end and eliminate each possibility in a methodical way.
I can understand your desire to start with 'the most likely' - it almost never works :)