At 00:43 26-10-1999 -0600, Dr. Green was heard to comment:
>With all the discussion of building your PCBs at home, and the
>wonderful VAX wars, I didn't think it was that far off topic :-).
Actually, it strikes me that building PCBs at home is perfectly on-topic
for the list if it involves re-creating "classic" replacement components
that are no longer made.
Case in point: DEC, at one time, made a supplemental +/-15V switching
regulator board that operated from about 36-40V input (monopolar) for the
H770 power supply (as used in some models of the 11/03 and others).
Such a part is, of course, no longer made, and several of the components
used appeared to be DEC-custom. With that in mind, I set out to design a
functional replacement. Fortunately, I was able to take advantage of the
tremendous strides in switching PS technology and PWM circuits that have
come along since the 70's. The new design uses perhaps one-fifth of the
original parts count, and the parts are all generic.
I have all the core active components sitting in a box at the moment. I
have enough to build two prototypes. Said prototypes will likely require a
two-sided PCB that I'm probably going to have one of the local board shops
do since I don't have the facilities or chemicals to do that kind of thing
here.
The only thing I'm waiting on now is a copy of the field maintenance
prints for the H770 power supply so I can, at least in function, copy the
control circuit that DEC used to enable/disable the regulator.
Anyway, that's just one example. As for the VAXen "wars," well, all I can
say is that the list does go through phases where stuff like that crops up.
Witness the gripe about the E-bay thread I made not long ago.
There's always the 'unsubscribe' option if it gets to be too much for you.
;-)
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner and head honcho, Blue Feather Technologies
http://www.bluefeathertech.com // E-mail: kyrrin_at_bluefeathertech.com
Amateur Radio: WD6EOS since Dec. '77
"Our science can only describe an object, event, or living thing in our
own human terms. It cannot, in any way, define any of them..."
Received on Tue Oct 26 1999 - 08:34:55 BST