I was at the ‘Retro Tech UK’ fair recently (which I would highly recommend) and on my third time round the room my eye was caught by what appeared to another variant on the ‘slimline’ design but was a little more expensive than the usual few pounds, and also had some odd looking controls. The seller immediately sprang into action, and told me that it was the “very unusual” Sony TCS-2000. I had never heard of this before, but he explained that the capstan (ie the thin metal rod which is used to drive the roller which feeds the tape through) was driven directly by the motor (rather than connected by the usual rubber belt – an universal point of failure in old devices) and that as a result it had lots of clever tricks.
First of all it mean that the tape transport was extremely accurate and reliable with the minimum of the dreaded ‘wow and flutter’ (being variations in speed which often result from slack or slipping drive belts). Secondly though it made some very special functions possible – such as running the tape at four times its normal speed, reading the high speed audio in and through digital processing playing it back at normal speed in 8s chunks. This means that you can scan through a tape much more quickly than usual but yet listen to snatches of audio played at normal speed helping you to work out where you are in the recording. You can also record index marks as you record and can skip between these again with high accuracy. The seller told me that the main market for these had been ‘the security services’ where they had been used to record interviews, and sure enough it came in a sinister-looking black vinyl case. That clinched it… although as I told the seller “you had me at ‘very unusual’”.
When I got it home, I did look around on the Internet but could find very little about it. There is one article on ‘Walkman Review’ which gives a good (if rather brief) summary of it, but beyond that – nothing. I did find the service manual, and a couple of mentions in catalogues from the time but little else and sadly nothing to corroborate the ‘security services’ story although it does sound plausible. What was interesting was that no other portable Sony cassette – not even the famous WM-D6 range – used this direct drive approach and this must make it one of the most technically advanced and accurate portable cassette players ever made.
I was very impressed by the sheer quality of the build. The controls are largely mechanical (rather than the ‘full logic’ electronic controls more commonly seen on high-end gear) but the keys are brushed metal and feel extremely solid. There are lots of interest looking buttons and switches on it, and very unusually for a unit like this it has two built in microphones providing for a stereo recording. One irritating – and important – thing is that like a lot of modern slimline units (but unlike the ‘classic’ ones from the 80s and before) it does not have a built in power supply and so you need to use either batteries or a 6V supply via a barrel connector. This is a ‘centre negative’ polarity – for some odd reason, as most are ‘centre positive’. I have found some audio gear (including synths, effects units etc) which have the same polarity. So if you don’t have the original Sony power supply (which unfortunately I don’t) then you have to be careful as most power supplies with this connector are wired the other way around.
So with it powered up properly, I was pleased to find everything working. I couldn’t resist hooking it up to my Spectrum and loading a few tapes and as expected the signal was rock solid and the games loaded perfectly. So whilst playback worked perfectly I did notice that on fast forward or rewind the tape wasn’t winding smoothly, and instead was moving in bursts suggestive of a worn or slipping belt. The motor for the winding mechanism is separate from the drive motor, which is again one of the unique features as usually it is the same motor for all functions.
So the next thing to do was strip it down and look for the problem… but this article is long enough so the story continues in Part 2.
Universal Discovery Methodology 