[vcf-midatlantic] Jan Workshop Report

Eric Rangell erangell at gmail.com
Tue Jan 15 12:43:17 EST 2019

I want to thank Todd for his excellent support in helping me diagnose the
issues with the C64 I purchased at Festivus.  We used the dead test
cartridge to identify suspect RAM, then a logic probe to check the levels
on those chips.  He desoldered and resocketed them and the machine booted
to Basic.  Also, Jeff gave me some leads on where to find equipment for the

I was able to plan my VCF exhibit, which will teach people the basics of
how to program a Replica 1 Plus by typing in hex codes to make it print
their name.  Or people can play Microchess with a Kim Uno or run programs
on the Replica 1+.  I got the Replica 1 Plus to use a Raspberry Pi as a
serial terminal, so that gives it a nice small footprint.  I also got
Plamen's Passport MIDI card (a2heaven.com) to work in a GS by routing wires
through the back panel to midi sockets on a breadboard.

I also built a 6522 chip tester using an Arduino Mega and Data Logger
shield - I soldered a ZIF socket to a PCB with ribbon cable jumpers going
to the pins.  I had previously worked on the test harness software, which
can be seen at https://github.com/erangell/RMChipTester   This will help
Henry C. identify bad chips from suppliers.  I still need to write more
test scripts, so if anyone is willing to help let me know.

At the end of the day I watched David G. give a fun demo of the PDP8 in the
museum.  He showed us how to enter the boot code and read and run programs
from paper tape.  Conceptually it all fits with my understanding of how
computers execute code - the only differences I see are the hardware and
the machine instruction set.

Thanks to all of you for your friendship and support - it means a lot to me.
Eric Rangell

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