-=> Roy J. Tellason said to Greg Mayman
 -=> about "POWER SUPPLY" on 12-07-03  04:05.....

 RJT> Yes,  it's proving to be the case here.  Concurrent with hardware
 RJT> issues,  too.  Until yesterday I never saw a HD where just putting the
 RJT> power connector in would prevent a system from powering up at all,  so
 RJT> I guess there's a problem in there,  and I have a thought or two on
 RJT> that subject,  like maybe a shorted cap or similar?  We'll see,  if I
 RJT> can find the time to mess with it. 

A dead short is usually one of the easiest to find, mainly
because it is so drastic a fault.

Intermittents are harder, but the ones I hate are where something
just draws more current than usual.

Some years ago I tried to isolate a fault on a digital delay unit
(used for telephone talkback on the radio) where the 5V regulator
suddenly was running a lot hotter than usual. I never did locate
the cause due to not being able to access the unit for most of
the day, as it was being used on air.

Fortunately it was still working alright last time I heard...

 RJT> Yeah.  At least I've collected a ton of schematics of assorted simple
 RJT> little circuits,  and may have the inclination to play with some of
 RJT> them.  I like the simple approach,  when it can be made to work.  Some

I've collected quite a few. If you're interested in getting more,
you could take a look at Electronic Projects Online...
http://www.electronic-projects.net/index.shtml

That's one of several sites with interesting circuits, sometimes
very trivial, but occasionally novel and interesting.

 RJT> stuff gets just too elaborate,  though.  There was one design I can
 RJT> remember where a signal went in the order FET -> optoisolator ->
 RJT> transistor -> SCR -> bridge (!) -> triac, which I thought was a bit
 RJT> much... 

I think I know what they were doing. OTOH it could probably have
been simpler.

 RJT> I've surely had enough of that,  stuff that isn't fixed is either
 RJT> going to get scrapped (like I need more parts!) or just tossed.  A

I still have a 5-inch National Ranger TV from about 1971 that has
a short in the p/s, probably a diode broken down. It's just been
waiting until I can find time to dig into it far enough to get to
the diodes, which is ###### awkward because of the way it's
built. But now I think I may have lost the screws for the case.

My original intention was to connect it to the video output of
the VCR, so I can monitor the VCR without switching the big TV away
from the program we want to watch. A very handy feature when you
need to copy something fairly long from a tape that has other
stuff on it as well.

But the local s'mart is selling 4" or 5" TVs with AM/FM radio for
only $30.... maybe I will scrap the old Ranger...

 GM> Maybe a description of the home of the Sodium family who invented
 GM> the Sodium vapor lamps that bear their name 

 RJT> Jeez,  I hope they don't start trying to collect royalties on table
 RJT> salt... 

Now available: "Sodium" (tm) chloride powder 

From Greg Mayman, in beautiful Adelaide, South Australia
   "Queen City of The South"    34:55 S  138:36 E

... I'd love to, but I'm uncomfortable when I'm alone or with others.
___ Blue Wave/386 v2.30

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