Nearly 30 years ago, zip ties, shrink wrap and hot glue were highly expensive luxury items for a poor student. You could not just order them from the Ebay for pennies/cents. So every hack was made using cardboard, electrical/painters tape and random re-used wires.
Disclaimer
All information on these pages is provided "as is". The information may be
misleading, inaccurate or completely incorrect. I take no responsibility if
you break, brick or in other ways demolish your assets after following
these instructions. These pages contain graphic images of violence towards
valued Commodore hardware. Viewer discretion is advised.
Complete mes[s|h], not easily dismantled nor understood.
I was tired of changing burned fuses after unsuccessfull reset with combination of scissors and user port.
Something more safe and robust was needed.
I have never come across reset-proof games faking CBM80 cartridge header in memory and thus needing unstoppable reset circuit.
Honestly speaking, I was not even aware of such thing at the time.
So I went the easiest route and shorted user port pins 1+3 instead of proper way of grounding pin 8 of 556 reset timer (U20).
The reset timer's active high output is inverted with 7406, which is Open-Collector, high voltage driver, so it should survive output grounding.
I had my Action Replay Mk.6 always connected, so it could have overridden any reset-proofing attempts.
Do NOT try like this at home!
On later revisions, Commodore split _RESET line to _INTRST and _EXTRST.
The external was connected only to IEC and line pull-down was driven directly from 556 reset timer via transistor, so it only activated on power on.
This was annoying, because some games put fast loaders to disk drive's memory and after the warm reset, the drive was still locked and required a power cycle.
One time in my life I became interested in how GEOS2.0 disk/program encryption worked (IIRC it involved XOR with some static value),
so I needed ability to reset the C64 and drive separately. I added additional reset button and source selection switch.
To my circuit analysis, overriding the Q3 _EXTRST transistor should not have any adverse effects, except allowing inbound reset from the IEC bus.
The Plan.
Excessive use of electrical tape.
1541 clones and Load-It datasettes being distant future and outside of price range, slowly loading from tape and having load error was the way to go.
Oh the joy when I discovered the Meaning of Life - err, the hole above tape head. Finally I could play the events on the B-side of my original World Games tape.
To improve successrate, I added switch, resistor and piezo speaker to READ input to be able to hear when I am closer to the perfect azimuth.
For some reason, I connected the speaker between read - write lines, and not to ground.
Using tape as your daily driver, you could easily train your ears to recognise starting and ending sequences.
Later I was introduced the mystical world of Turbo Tape 3, which allowed the same prosedure with red and black stripes.
To have many more happy years (in storage), I planned a mission to cleanup the past 30 years.
In the retro recipe would include recapping, heatsinks, Artic MX-4, IC socket, Fairy/Windex and more eye-pleasing wiring.
History in the making.
Axial capasitors are getting hard to acquire and many recappers on Youtube try to re-create them from radial ones with leg extensions and tape/shrink wrap.
For some reason in its infinite wisdom, Commodore engineers have had a premonition and placed pads for both axial and radial capasitors, even in 2 different pitch.
So you may have a nice and robust rework (with hot glue).
Please clean flux residue - it can go quite hard after 25 years.
PC front panel accessories and HP Blade heat sinks in better use.
Jump to
Part 1: Main Attraction
Part 2: Expanded Universe
Part 3: Power supply