[rescue] Rescued iMacs looking for input on repair

[James]

> Bill Bradford wrote:
> >
> > On the other hand, we had a tech support guy / stoner who would
> > discharge CRTs with nothing more than a large, long flat-head
> > screwdrive and an impressive "BANG!".
> >
>    I have a question after reading this: you kept a stoner _on staff_?
>    Wait, no, I have a different question: how can you discharge one of
> these man-almost-killing capacitors without getting zapped? Does the
> metal implement have to be grounded to something (besides your central
> nrevous system)?
>     Not that I'll ever do it, since I know that I *don't* know which
> parts are the scary ones inside that metal shield that lines a CRT case.
> -wde


Not that I'd keep a stoner around, but us crufty greybeard types grew up
discharging CRT envelopes with screwdrivers. Snuggle a flat-tip screwdriver
under the rubber anode cap and swing the shank toward something chassis like
and *snap*. In fact, if I didn't get a snap I didn't trust it was
discharged. I've been known to fire up the chassis again to charge the tube
so I could discharge it again if I didn't get a snap. If I still didn't get
a snap I would fire up the chassis and leave it *on* and discharge the tube
to see if I had HV. Sometime after tube HV circuits disappeared I found that
this could damage circuits. Of course, this was back in the day when the
integrated circuit was a neat new idea and a company called Intel didn't
exist. Companies like Transitron ruled the IC world.

Oh, it's time for my Geritol, gota go.