RE: 19K6400

From: Clay Cowgill <ClayC_at_diamondmm.com>
Date: Fri Jan 23 1998 - 14:55:02 EST

> Another thing that would have to be added is an overvoltage clamp on
> the
> output of the regulator, since if the Vin to Vout voltage is greater
> than
> 40V, then the regulator will burn up. This will not be a problem with
> installing it into a standard WG6100.
>
Been a while since I tried any LM317 tricks, but let's say we have
40-0-40 input into a full-wave bridge rectifier. We'll get about +/-57V
unfiltered DC out, yes? (.707*80) Hang a couple big 4700uF caps (ugh,
I'd really say you wany 100V caps there) and figure our input to the
voltage regulators is about 56V DC. We want +/-47V, so we need to burn
off around 10V with a regulator setup. We want to use a standard LM317
and LM337, so is the way to do that just to raise the "floor" the ADJ
pin up to (let's say) 18V with a zener. So the input is 56V, the output
is set for 46V, but the "adj" voltage sets virtual ground as +18 so the
regulator "sees" Vin of 38V, output of 28V and it'll burn off the 10V
delta. (Actually, you could probably play some input games and get an
input voltage closer to the regulation voltage and save some heat...)
Does that sound right? My power supply design skills haven't been
exercised since high-school electronics class. ;-)

         You must understand, when I designed this upgrade kit it was to
fix the
> problems with the WG6100 monitor. I never intended to also have it
> work
> for the "sega" type of vector monitor.
>
Ahhh, just you wait. I'll put it together with an 80W Weller
pistol-grip soldering gun (with the little light-bulb that turns on when
you pull the trigger) and then send it back and complain that it doesn't
work in my GO-7. *laugh* :-)

-Clay
Received on Fri Jan 23 11:56:00 1998

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