Mac II startup failure

[Kallikak]

Here's a strange one. With absolutely no warning, my Mac II failed on me last night. After having gone to great lengths to put this machine together (I got it in parts from several places) I was quite upset by this, although I wasn't about to start to panic without having had a good try at fixing it.

The symptoms were normal startup chime, then either no raster, or partial raster followed by half the chimes of death. That's right - it would get half way through the chimes, and then stop! Go figure... :?:

Anyway, I thought it was most likely a NuBus problem - I have 2 video cards and an Ethernet card in there, so this evening I opened her up, and started taking out cards etc seeing if I could get it to boot. Eventually I did, but wasn't sure exactly why, but was happy enough and I put the lid back on and started her up again.

Same problem... :-(

So I stopped and tried to think what was different between this time and the previous time when it worked. Well, when testing I used my spare keyboard, but when reassembled I used its usual keyboard. Could that be it? Short answer - yes! This keyboard goes via a KVM, and it seems the cable was coming loose. Not yet loose enough to stop the power-on button, but loose enough to cause this strange behaviour on startup!

So, there is a happy ending to this story, but I thought it worth mentioning and adding this experience to the general troubleshooting pot. Would have been much easier to just plug in the cable properly last night and save a day of worry and all the bother of taking it apart etc.

Nevertheless, on the whole, the experience was quite satisfying.

 

[equill]

That all such frustrations should prove to have simple causes. It does carry a moral, though. In defiance of logic, always look at the least obvious cause first. If you can discern the least obvious, that is.

de

 

[LCGuy]

Indeed, equill. A few years ago when i did work experience at an AASP a tech there gave me a very useful piece of advice for whenever i'm working on a challenging problem: Assume nothing!

 

[equill]

For us AR types, it is summed up the axiom from the carpentry/joinery/cabinetmaking world:

Measure twice. Cut once.

de

 

[Charlieman]

Kallikak's problem reminds me of a Mac many years ago that would only start with "Extensions Off". The cause was crisp (US: potato chip) fragments underneath the Shift key.