Yes, I have to agree with you. But wonder if something ancilliary to keyboard was affected when I took old one out/put new one in. One has to turn the machine over and its not very rigid once KB, batteries, CD drives are out

I guess I can remove & reseat wires again...

Have noticed that, on reboot, num lock light is sometimes on & wonder if its something to do with connections in that direction

I tested the hard drive with Hitachi's utility and ran Dell diagnostics and of course everything was OK

it is possible you fried something in the whole process.

But since all is working on very low voltage/amperage that rarely happens. Do you still have the old keyboard ? If that was not dead maybe when you put it back at least you are back to the situation you were in before the swap. Sounds to me that's a better starting point than you have now.

Otherwise look at the keyboard again.

Good luck !

 

Yes I do have the old keyboard -- and indeed, as it was the 'M' that was permanently faulty , perhaps I should have yet a *further* go at cleaning the contacts under the plastic 'M' letter cap, and then reinstall it and see....

FYI, I had a good look at the underneath of both KB's and the seating arrangements in the dell. Its clear that theres a number of contact points to earth the aluminium panel which forms the underneath of the board -- one near right edge, one on left, and 6 curious little ones top right the num lock/Pause/Indert etc etc etc keys are.. My old keyboard shows very pronounced contact points with these, and Im surptised as the springiness of the contacts involved wouldnt immediately lead one to think that the contact would be so 'hard' (I presume that in part theyre something to do with ensuring good circuitry to the key that switches on monitor lights, viz num lock and scroll lock, as well as the others in that segment in KB) . Anyway, I cleaned ALL contact points with a high-volatile electrical contact cleaner, carefully did the ZIF and the ribbon connector attacchments and reinserted the whole caboodle...Have tightened up only with moderate firmness...!

Its booted up OK...but sometimes it'll be fine for days and then just go black. So I have to wait and see. It teaches one to Save' like nothing else...

I somehow dont think I fried anything...am moderately conscious about earthing, but, who knows...certainly in its 'good' periods the machine's so good one would doubt that somethings fried... Yesterday was a bad day so I'll wait to see if this is better

thanks for the heads-up.

I hope you get this sorted out.

good luck !

The bad news first:
It black screened again
Attempts to reboot fail (as in previous episodes) after about 2 seconds after pressing the 'On' button

Now the good news
I de-tension (but dont fully undo) 3 screws holding top ('Northern') edge of KBoard
It reboots. Was fine all day yesterday and so far this a.m.

Strange isnt it. Makes one think KB is pressing against something or something is pressing against KB. Yet cant see any obvious difference between this new KB and original one

keeping the 4 most 'northerly' keyboard screws quite loose seems finally to have worked. Tightening just 1 of the more southerly ones to 'compensate' caused a black screen. Loosening it again seems to have rendered it stable.
Strange...