Random Commodore Plus/4 hax

… or I’ve simply lost some pics


This post should’ve been written a long time ago but I’ve simply lost pics… This is the reason why I’ve called it “Random Commodore plus/4 hax”

Long story short, I’ve purchased eight broken Commodore Plus/4 machines. As usual, all machines had to be fixed, cleaned and retr0brighted. In this post I’ll describe some of the fixes that I’ve applied.

PSU socket

I don’t have an original PSU for Plus/4 but since the voltages are the same as in C64s, I’ve figured out that I can replace original sockets with the ones used to power up C64 ๐Ÿ™‚

This hack is quite straightforward. All I had to do was to de-solder original square sockets, remove unnecessary pins from round DIN7 socket and solder it on the motherboard.


All the keyboards required cleaning and some sets of key caps had to be retr0brighted. Rather easy job ๐Ÿ˜‰

Key cap studs

Some of the key cap studs were broken and I had to replace them. I didn’t have spare original studs so I’ve used studs from Mitsumi keyboard of Amiga 500 keyboard. However, I had to trim them a bit.

GND Springs

Some of the keyboards were missing tiny springs that connect a GND signal. I’ve made new ones by cutting a small spring that I’ve found in my spare parts.

Power LEDs

There was issue with broken power LEDs. The problem is that these LEDs are not standard and are not available in online stores nowadays (at least I didn’t find any).

Here is a comparison with an LED that are available – standard rectangular LEDs

I’ve figured out that I can trim these LEDs to a desired size.

Here is how it looked.

SD2IEC and CPU replacement

On the electronics part, I had to replace some of a fried 7501/8501 CPUs. That was easily achieved by using a an adapter for 6510 by hackjunk.com

This is a very smart hack by hackjunk.com which allows to use a C64s 6510 CPU. The drawback is that original ROM has to be replaced too.

I’ve also installed an SD2IEC inside some of the machines. This is an SD2IEC of my design. More details described in this blog post.

Finishing touches

The problem with dark plastic is that after cleaning, it becomes matte and looks like it was treated with a sandpaper.

To bring back original color I usually use a thin oil – a baby oil for example.

Final words

Like I’ve written at the beginning, I’ve lost most of the pics for this post and I cannot fully describe everything, however, I think that presenting above hax was still useful ๐Ÿ™‚

I’ve managed to fully restore five machines. The remaining rest has to wait for MOS TED replacement The ThED project – which is still undergoing heavy testing. Covid-19 and the mouSTer project slowed ThED down a bit but we will be fully working on it soon.

This is it for Random Commodore plus/4 hax post. I hope you liked it ๐Ÿ™‚


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7 thoughts on “Random Commodore Plus/4 hax

  1. Did something similar today, was wondering if anybody has thought about changing the inbuilt software, perhaps replacing the painful word processor with fb16 etc?

  2. It was a nice read! Thank you for saving those underrated machines. You may see some wonderful releases in the future, as some very talented guys (programmers, graphicians and musicians) started to support this platform since few years, and already made great releases, like Pet’s Rescue. With the SID card available, the main hiatus of the range (proper sound) is also corrected, and also worth to mention the recently announced AY card too (a much cheaper alternative for music generation, the same used by ZS Spectrums 128K and ATARI ST)

    Now what is coming…

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