component, it might account for my being able to reset the computer by
probing the comparator output with my 20kOhm VOM. I'll look for it, too.
>Right, that's related to the problem. The comparator seems to be working
>correctly.
It does appear to be comparating (is that a word?) correctly but I'm still
not convinced its input impedance remains low all the time. But now I know
that I have more parts to look for. Sigh.
>A dry joint is more likely -- SMD resistors are normally reliably. A dry
>joint could cause problems, though -- maybe worth resoldering things. And
>I rreally would suspect the orange thing is a capacitor.
Dry joint on a cap. has no effect in steady-state, right? I mean, a cap is
an open circuit to DC, so there's no way the system would fail once
started, if there was an intermittent open on either end of a capacitor,
right? (Also see below.) I'm assuming all this stuff *is* DC...
When I get the iron heated up, I'll try to re-touch the resistors if I'm
feeling cocky. But I think I'll try to replace the comparator first.
<plastic rivet dry-wall anchor monstrosities>
>To be honest, I'd not care about mangling them.
I got them out intact. Now I have to decide between (historical
correctness) and (convenience next time I disassemble). Hmm.....
Wizard also chimed in:
>Yes it is a talutum (sp?) cap it's orange body and did it has tiny
>pip on one end? That's polarity, and much thicker and usually square
>cross section.
There *are* a lot of those, and they match that description exactly. The
6192 has a different form factor, identical to that of the black 1152
beside it. Going against two luminaries such as Tony and Wizard
simultaneously is the mark of a fool, but I'm still thinking this guy is a
resistor. I did not see a polarity pip on it (now that I know what that is,
I'll look again, though), the color was a slightly different orange, and
the shape matches the supposed resistor (1152) beside it.
Plan for tonight is probe some more (as above), then replace the
comparator. My wife did actually pick up replacement comparators. She said
the guys at the electronics place gave her a really funny look. She walked
in with the 2-year-old and the 6-year-old (offspring), and asked by number
and name for the IC's I wanted - without referring to her notes. Guess that
doesn't happen too often. Anyway, I now own $1.30 worth of spare
comparators, and I'd rather solder on the IC than on the SMD's for my first
effort. Besides which, I don't yet own replacement SMD resistors, or caps,
or whatever the heck they are.
If no joy with the new comparator, I can try to retouch solder joints on
everything connected to the voltage divider. Anything to look out for when
dealing with SMD's with a cheapo soldering iron? :-(
- Mark
Received on Sun Feb 27 2005 - 13:22:22 GMT