-=> Roy J. Tellason said to Greg Mayman
 -=> about "POWER SUPPLY" on 01-03-04  04:06.....

 RJT> Absolutely.  It's gotten me downright schizoid in terms of the way I
 RJT> deal with this technology.  There's the stuff I _use_,  and don't mess
 RJT> with,  because of things like the above,  and then there's stuff I mess
 RJT> with,  which looks to be a decade or two behind the times.  At least.

Yes, my feelings exactly.

I hate having to troubleshoot surface mount stuff.

A friend bought a secondhand modem a couple of years ago that
would NOT pick up the telephone line on an H1 command, but if you
lifted the phone that was also connected to the line, the modem
would grab it OK.

He got fed up with the thing and gave it to me.

I traced out the circuit of the line grabbing bit -- all surface
mount so I had to use a 3x magnifier -- and found a three
transistor circuit with a couple of resistors and a capacitor
that would act rather like a series connection of an inductance,
a resistor and a zener, to load the line in the offhook mode.

But the odd part was a fourth transistor that would short circuit
the base-emitter of the first one of the above three if the line
was above about 20v, thus preventing the circuit from grabbing
the line.

Of course if you lifted the phone that was also on the line, the
voltage dropped to about 10v, this fourth transistor turned off,
and the other circuit could then loop the line as normal.

I have no idea why the manufacturer -- Hayes of all people! --
included such a ridiculous arrangement. I soldered a wire bridge
between base-emitter of this fourth transistor to stop it from
turning on and blocking the other circuit. Now the modem works
just fine!

 RJT> I've not got a real good picture of what today's hobbyists are all

A quick look at a few copies of Silicon Chip magazine (Australia)
shows projects for
*  a valve (tube) audio preamplifier
*  a 350w audio power amplifier
*  an IR remote controlled motorized volume control
*  a 0-80A LED ammeter for cars
*  an ultrabright LED torch
*  an efficient power supply for a 1W ultrabright LED "star"

and that's just a three issues that came readily to hand.

 RJT> about.  I used to get the magazines regularly,  and have pretty much
 RJT> stopped doing that except for having recently started buying
"Nuts &
 RJT> Volts" again.  And too much of the stuff I've been finding on the 'net
 RJT> is at a pretty basic level,  or it's people who are doing things that I

Yeah, that's waht I've found. I discovered a couple of sites with
some electronic novelties but most of them are very, very basic
stuff.

 RJT> wouldn't,  like robotics and such.  I still can't get over this one
 RJT> site where the guy chronicled his spending _seven months_ to get to
 RJT> where he could cast these housings for "homebrew linear
bearings" for
 RJT> some sort of CNC machine.  Casting aluminum?  Not me...! 

Nor me!! It sure sounds like the hard way to go.

Bronze is usually considered as a better bearing material, and
sintered bronze bushes aren't all that hard to buy off the shelf!

 RJT> True.  Although I've avoided scrapping any parts off such stuff so far
 RJT> I have once or twice been tempted to do so,  just for how small you
 RJT> could make something.  Though small isn't necessarily a big deal with
 RJT> me either. 

A friend of mine has a tiny TV set he made in Britain in about
1950 for his entry in a Radio Club competition. Apart from the
p/s the whole thing fits in the palm of your hand!!!

OTOH watching TV on a 1-inch screen, and with no sound, has its
drawbacks 

 RJT> Yes it is.  I closed up my shop back in 1992,  and at that time a guy
 RJT> who worked there had a lighted magnifier that I was making pretty heavy
 RJT> use of. I've since acquired one of those myself,  and just recently had
 RJT> to clean all the flux fumes off the lens.    There are
also a couple

I keep saying I must buy one. Occasionally I see them on sale
under Aus$100 (current price from one retailer is $99) but that
always seems to coincide with a rush of bills that I have to pay.

So I make do with a couple of hand-held glasses, and two pairs of
magnifying specs, but those big illuminated ones are just so
handy that one day I _will_ get one.

And they keep the flux fumes out of your face -- very important
to me these days when I have to work so close to the job to see
what I'm doing 

 RJT> OTOH on my linux box I'm running a 132 column by 60 row screen,  and
 RJT> find it quite readable.  

My guess is that you have a monochrome VGA monitor... those
things give beautifully high definition that you just can't hope
to match with a colour monitor.

I hope your new year is starting well, and continues that way!

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

... Intuition is reason in a hurry.
___ Blue Wave/386 v2.30

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