27 Nov
2007
27 Nov
'07
2:23 p.m.
Roy J. Tellason wrote:
When we had the shop there were a whole lot of times
that you couldn't tell
which chip was bad without trying a new one in there, and the dropping
prices of the machines made wholesale replacement of parts impractical, so it
was a policy of mine to *always* unsolder the chip and put a socket in there.
In the interest of full disclosure, I remember the ROM chips were always
socketed, but my many "educational" endeavors on the machine (and the
occasional lightning strike through the modem telephone line) caused a
number of trips to the service center for repairs.
The place that got all of my business (Micro Pace Computers in
Champaign, IL, later called Keepin' Pace Computers) applied your rule,
so my SID, CIAs, and RAM ended up socketed, making my machine very valuable.
1764? With the VIC20, I find the two-pin power
connection to be the
preferable one.
Yes, if you have the 2 prong VIC, it's solid, as the regulation and such
is done internally. Though, 2 pin units seem to not be as common, as
CBM switched over to DIN pretty early on. Thus, many folks guard those
machines and the PS units. I assumed an everyday VIC user has their 2
prong unit boxed, as I do, and messes with things on a later DIN unit.
All that said, the VIC had lower power usage and tended to not have an
expansion port extended with multiple items drawing power, so I never
had a VIC PS fail per se. But, the near max draw of the 64 (they
re-used the VIC PS design and specs for the 64, as I recall), coupled
with the plethora of expansion options for the 64, overburdened the
struggling supply.
To be fair, it's entirely possible the PS was fine and would live a
reasonable life attached to a bone stock 64. No one actually owned a
bone stock 64 for very long, though. Once you had overloaded them, it
seemed only a matter of time before they would fail.
To try to add some new information, the VIC/64 joysticks should not be
overlooked for small IO projects for kids. DE9 female sockets are easy
to find, and there's Vcc, GND, 5 pins of IO and 2 pins of 8 bit ADC
available for the taking per port. In fact, using both ports with a bit
of ML and a nice BASIC program, you could make a nice electronics
trainer for possibly multiple machines (It looks like the Atari variants
had true joystick IO ports, but I know very little about the Apple and
TI units. Google says Atari created such a trainer for their 400/800
units, so the idea held some merit.
Quite honestly, that is a neat idea, and one that would be easy to
implement. If there's some interest, let me know.
Jim
--
Jim Brain, Brain Innovations (X)
brain at jbrain.com
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!
Home: http://www.jbrain.com