Not too hard [Aiwa AD-M100K]

Yesterday I turned to resurrecting the Aiwa AD-M100K stereo cassette deck. This is quite a nice straightforward machine but the design is very much of its day (1980) and showing its age. It has mechanical tape loading via piano keys, single direction transport, analogue VU meters and no frills. But it was typical of the kind of stuff I was using at the time.

This one had toffee drive belts and although the motor hummed, that was all. I couldn't find any service info but the nice people at Vintage Cassette have a spec sheet here.

After lifting the lid I did some measuring using the tested method of wrapping ribbon round the belt path and overlapping it, then cutting both ends together. This gives the length but be careful, some suppliers quote "length" meaning the belt laid out in a line but still intact - so their "length" is simply half of the measurement. Other suppliers use the diameter of the belt in a circle as "length", including CPC Farnell who complicate matters by referring to the height and width of the belt, meaning the width and thickness as I would call it. But hey ho, it keeps the brain from coagulating I suppose.

This deck needs four belts, which I got from CPC as follows:

Capstan belt: AVBELT4 - flat, 69mm dia, 3.5mm wide, 0.5mm thick
Auto-stop drive: AVBELT78 - 38mm dia, 1.2mm square section
Tape counter primary: AVBELT92 - 52mm dia, 1.2mm square section
Tape counter secondary: AVBELT66 - 28mm dia, 1.2mm square section

These are just what I could find which worked - there may be others. You can pay a lot of money for a dedicated set of belts specifically for this machine, which might just be these ones re-packaged with a fiendish markup. I notice the 'set' suppliers never list the belt sizes in their kits!

The tape transport mechanism can stay in place - I just removed two screws (mid left and bottom right, out of direct sight) which allowed the backplate to hinge away and give space to thread the capstan belt through, followed by the auto-stop belt which runs off a coaxial pulley on the flywheel. I then re-fixed the backplate and fiddled for ages to get the two belts around the flywheel rim/motor pulley and the flywheel pulley/autostop pulley respectively. Then check that it all worked - success! Pretty well everything on these is done mechanically so once the drive is back, only the tape counter didn't work. This could have been tricky but there is enough space around the take-up spool hub, where it passes through the front plate, to thread the belt in. You then catch it from behind and stretch it up to the idler pulley top right, and then add the last belt from the idler to the tape counter.

That was all there was to it this time - I spent the next hour or more listening to Pavarotti's Greatest Hits (Decca K236K 22, 1980) which was very appropriate, just the kind of thing I might have played on it in 1980. It works beautifully. While I listened I put together a full description for the blog, peppered with snappy witticisms and useful tips. Then when I went to publish it, there was a 'Save error' and Firefox crashed, losing the lot. That's why this account is a bit boring, coz I can't be bothered to do it all again.

(Postscript: I found that using copy & paste doesn't work in the blog for inserting images. The image appears but the uploading during Save or Publish gets a bit sniffy with the Javascript...)