Friday, 6 September 2013

C64 datasette 2nd revision [Hacks/Mods]

As detailed in my previous article, I managed to successfully modify a standard datasette for external line in by intercepting the wires between the tape heads and the datasettes control board.

In this article I will show the latest revision.

I returned the previous datasette to its original condition and stripped the control board from a unit with dead motors. To start with, I desoldered all the original wiring to the tape heads and gave all the points a fresh ball of solder. After the board was prepared I set about soldering in the new input socket that would replace the head unit, I would have chosen better parts but I used what I had to hand.

In this attempt I decided to wire the line in socket exactly as before but remove all surplus equipment. In my prior attempt I had concluded there were just 3 main points to use with this method. Should I revise further I will wire up data out too, but I simply didn't have the parts... plus I would never use it...

The net result of doing this was the unit needed almost half of the 'volume' from my smart phone and was significantly more reliable. I am considering adding resistors to impede any distortion but for now it works fine.

I was able to locate the leaf switch that tells the computer it's datasette is 'playing' and simply remove it and join the circuit directly to ground at the board which allowed me strip even more redundant hardware out.

The final board ended up so small I fitted it internally but left its original connector in place so it could be removed should I use another solution through the datasette port.

While the unit was dismantled I took the opportunity to add video and sound sockets, this is insanely easy to do as it is just 3 solder points... In fact the hardest thing was committing myself to drilling the casing! I sent the audio to both available audio sockets for fake stereo. To finish up I made a small lead to connect my 7 inch screen to the C64 to save mess.

It's probably worth mentioning this solution is best used with PRG files, they seem the most compatible with Tap Dancers turbo loaders. Other formats work but it can be a pain to find the correct loader option at times. Also worth mentioning I had to set the software to 'inverted output signal'  and find the correct volume which for me was '7'.

Should you have any suggestions on how to improve this solution further please add your thoughts in the comments box.

Certainly saves a lot of messy cables!


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