Although I'm in the UK, I have much more experience of the Tandy CoCo -- I even have a CoCo3 here. The Dragon 32 and CoCo 1 are pretty similar (based on the same Motorola application note), but alas the PSU is one area that's different. I do haev a Dragon 32 that's not too hard to get to. If you get no other help, I'll dig it out and trace out the schematics of the PSU board (shouldn't take too long). I'll need them myself sometime anyway... -tony

The Dragon and Coco are similar on the 'computer' side [1], but the PSU is rather different. The Dragon has an external transformer box that connects to a DE9 plug on the back of the Dragon. Inside the Dragon (I've just looked) there are 2 PCBs. One is double-sided, glassfibre, and contains the 'computer' stuff (6809, 6883, 6847, RAM, ROM, etc). The other is single-sided SRBP, and contains the PSU, modulator, and video output socket (the Dragon has a 3 pin DIN video output, the connections being audio, ground, composite video in some order). The 2 PCBs are connected by a short length of ribbon cable with a plug/socket on the 'computer' board. The PSU circuitry consists of 8 diodes (forming 2 bridge rectifers, one to provide the +5V supply, the other to provide the +12V, -5V supplies from a centre tapped transformer winding), a few caps, and 3 3 terminal regulators for the 3 supplies. There's nothing 'clever' or unconvnentional about it. [1] The main difference is the printer port. When you've taken over the lines for the keyboard, sound, etc, there are 3 PIA lines left. The CoCo uses them to make a bit-banged serial port (2 inputs, one output). The Dragon uses them to make a centronics port (strobe, busy, acknowledge IIRC). The Centronics data comes from the same port that provides the keyboard scan outputs. Since the printer only looks at that data when the strobe line is active (and it's not active during keyboard scanning), and since the CPU doens't look at the keyboard inputs when it's printing, there's no conflict here. I assue he's in the UK. The Dragon is much more common over here, I think. And his domain name looks like a UK amateur radio callsign (am I right?) The cassette format is the same at the bit level, and even at the file level. The problem is that the BASIC tokens were assigned in a different order (for what reason %deity only knows!). So ASCII BASIC programs will load into both machines, as will some machine code programs (provided they don't use ROM calls that are different on the 2 machines). Tokenised BASIC programs will load, but won't run, and the listings are garbage! If you just copy the cassettes to audio CDs, then I can't see why it won't work (although I really can't see the point of doing this -- if you want to preserve the recordings I'd not use a CD!). But I would have thought you could interpret the data on the tape and make a much smaller file that was essentially a bit image of the 0's and 1's on the tape. Then convert that back to the right audio format to load it into the Dragon. The format of the tape data is documented in the CoCo service manuals, etc. -tony

Ye gods, are they still selling those? I bought 2 of 'em over 2 years ago now. It was almost worth it just to have a laugh at the catalogue since it looked like they hadn't updated it since the 1970s! Looking round the website now I'd hazard that most of the pages haven't been updated since 1995 - wow - a dual speed external CD writer with 1.2gb drive for *gasp* $2695! http://www.binarydinosaurs.co.uk/Museum/Tano/tano.php One of these days I'll see if one of them powers up with a standard UK Dragon PSU. I cheated when I got mine - I was over in Nashua for a Compaq 'do' at Digital's old Nashua HQ so I had my machines shipped there and brought 'em back myself. Cheers w