Can you hear me, Mother?

 About three years ago I acquired a pair of Amstrad CPC464s. One I sold on to help pay for the initial outlay on the bundle (which also included my Plus/4) but I kept the other as it wasn't in the greatest condition and I had, to be honest, never owned a CPC before.

Clear the decks! It's huge!

As part of my escapades with the CPC, I added an audio in mod. This allows me to load games via the sound output of my phone - or anything else with a 3.5mm audio jack. Unfortunately, I'd found that it was quite unreliable and would not load a lot of the games I'd managed to find on the internet. I put this down to the software I was using to convert the .cdt format files to .wav format being a bit flaky and my phone not outputting the volume loudly enough. And so I put the CPC away for a long while; I even pinched its Z80 processor to assist in the diagnosing of a poorly ZX Spectrum +.

Oi! That Z80 is MINE!

Z80 restored and ready.

Fast forward a couple of years and there is a rather excellent YouTube channel called "Noel's Retro Lab". As the name suggests, a very nice guy called Noel repairs and explores retro computers and games systems. And as luck would have it, he dedicated a whole video to the exploration of modding the CPC with an audio in jack. See that HERE.

To cut a long story short, my original mod was incorrectly fitted. I had attached the inputs to the actual cassette read head. While this did work it did have a couple of disadvantages. First, it seemed to need the 'Play' button pressed to pick up the input. Second, as mentioned above, it wasn't very reliable. 

The NRL video is very detailed and well worth a look but, very simply, by moving the '+' side of the input to the correct side of capacitor C317 (the red wire), this meant that the input signal would pass through the op-amp circuitry of the CPC, giving a strong and stable signal at just the right location. And no need for the tape 'Play' button to be pressed.

New wiring - thick black
and red wires re-soldered

I also moved the black negative wire from the play head to a more generic 'ground' connection. It probably wouldn't have made any difference but not really worth taking the chance.

And now... how to be a complete freakin' moron.

As suggested, I also have a ZX Spectrum on my bench which I was originally going to try with my batch of cassette recorders. I had problems though (another post inbound on that) so I re-focussed on the CPC. 

But guess what happened. I had two power plugs on the bench. One was 5v max current of 3A with centre positive plug, the other was 9v max current 1.4A with centre negative plug. When I plugged in the power and switched the CPC on, nothing happened. Guess which one I had plugged in to the CPC? (I'll give you a clue - it was the wrong one.)

!

Oh. S**T.

Fortunately, my immediate incompetence was saved by past me making the competent decision to unplug the 9v 1.4A centre negative supply from the mains. Bullet well and truly dodged.

Anyway, with power now sorted it was time to see if the mod now worked. Since it was a long time ago that I last used the CPC I had long since lost the .wav files I had of the couple of Amstrad titles I'd found. My hard disk has also been changed out in my laptop for a nice shiny SSD following a hard disk failure too so I no longer have the software that converted the .cdt files to .wav. I finally managed to find an Android app called Tapdancer. This takes the .cdt file and plays it directly out of the headphone socket of my phone. It's quite old though, and is not on the Google Play store. As a result I can't really recommend it but it did work for my test purposes.

Next problem. Finding something to load. Eventually I found a .cdt of a Spanish motorcycle racing game. Google is your friend.  Tapdancer happily accepted it and converted it but, would it load? No. Not initially. The problem though was that the cable I have kept popping out of the headphone socket on my phone. I suspect it has 'had it'. A bit of fiddling later I managed to get it to stay in.

Would it work on the second attempt? Yes. Flawlessly.

Speccy photobomb

It works!

On the first load I realised the game was in Spanish with no English option. This was a problem when I re-defined the keys and ended up with the directions and acceleration all mixed up. Not the easiest game to play with keys like that.

Next up, WEC Le Mans. And it was the English version so I could at least get the keys re-defined correctly. 

I like all racing games. Even this one.

And, again, it just worked. After about five minutes the game started straight up with no complaints. The game itself seemed OK for the time i.e. it's no Gran Turismo. With only one apparent track and quite hard time limits it's quite difficult but the graphics are cute, especially when you crash and the controls are OK, if a bit slow. I'd give the game a solid 6.5/10. 

And that's basically it. The CPC now works quite happily with .cdt files playing directly from my Android phone. The only thing I have left to do is find that piece of software I originally had that converted .cdt to .wav in case I feel the need to try a direct player (instead of TapDancer).

The CPC is also proving to be the most solid and reliable machine I have. Nice.