Denial

You just have to love engineers. I'm not sure if this was posted on this forum before, but here is the FULL STORY. Fun read. Any thoughts on these mods?

Jeff-20 wrote:Any thoughts on these mods?

Posts about heavily modded VIC-20s come up once and again (that particular example springs to my mind), but I think this one had not been mentioned thus far.

Main 'issue' I think about those mods (what I also wrote in the other thread): mostly, there is no detailed documentation how the mod what performed, let alone something like a circuit diagram - which then makes those mods a one-of-a-kind thing. That is o.k. if such mods merely 'collect' a selection of cartridges - tools/games or RAM expansions - in lieu of a cartridge extender. But if they actually provide a capability that could not be provided by a simple combination of cartridges but rather require an actual modification of the mainboard circuitry, then you are lost without a schematic.

I wonder if those venilation holes are enough?

Rectifier and voltage regulator have been removed (an external power supply is used instead), and these are the biggest heat sources beside the VIC chip in a 2-prong VIC-20. Anyway, there is also the open cartridge port, so there ...

Where’s the JiffyDOS button?!

chysn wrote: ↑Sat Jul 30, 2022 7:03 am Where’s the JiffyDOS button?!

I’m sure if it had been available at the time this was made, he would have added it.

Hey everyone: I JUST discovered your site! This is the guy who modified his VIC-20 so he could use it for engineering school.

Here are some answers to your questions:

1. The upper interface is exactly as Mike predicted. The only mod was the addition of the 1 meg bias resistors that you see on those expansion boards.
Without those resistors, the system becomes unstable and crashes.

2. Mike: You called it. With the power supply components removed, there's literally NO heat inside the Vic. I'll post some pictures of the inside of the
power supply. I basically moved the parts from the VIC over to a separate Radio Shack box, except I had to use a different heat sink.

3. JiffyDos would have been cool but it wasn't available back then...

Either RUN or Ahoy! magazine wanted to run a story about it and I still have the latter from them somewhere. But by that time, everything was for the Commodore 64.

If you're still interested, I can whip up a schematic for the Power Supply.

John

Hi, John,

W3AFC wrote:Hey everyone: I JUST discovered your site! This is the guy who modified his VIC-20 so he could use it for engineering school.

first of all, welcome to Denial!

With the power supply components removed, there's literally NO heat inside the Vic.

There had been some heated (pun intended) discussions now and again here in the forum, whether a heat sink on the VIC chip is necessary (my bet is on the "no" side - there's enough cooling through the pins and wide PCB traces on the underside of the board already -, IMO adding a sink just increases the heat capacity near the chip and keeps it longer warm when switched off ...).

I've had my own share of extensions/changes of the mainboard, the VFLI mod, an own variant of the S-Video mod, and a new bug-fixed BASIC ROM in particular. Also my MINIMON cartridge could be regarded as mainboard extension, as it effectively goes between mainboard and any other cartridge. Maybe one of these could spark your interest.

When it comes to software, take a look what has been released as tools or games for the VIC-20 in the last years here: https://sleepingelephant.com/ipw-web/bu ... m.php?f=15. Having a more modern mass storage solution like SD2IEC drives makes it much more easier nowadays to transfer stuff between PCs and the VIC-20.

Greetings,

Michael

John, you should be very proud of that build, it's a beast. I'm amazed at how much you were able to cram in that case under the keyboard.

Out of curiosity, with all those bells and whistles attached, did you ever measure how many amps the 5V rail pulled on your Super VIC?

How often did you use the Protecto-80 output over the stock VIC-I output, and what sorts of things did you do using that add-on?

As Enzo from Reboot would say... "That's alphanumeric!!!"