8 track cassette capstan motor tascam 238 syncaset

We specialise in tape transfers, especially cassette tapes.

Tascam, Fostex and Yamaha sold cassette multitrack recorders in the golden days of home recording in the 1980’s and 90’s. The 4 track format was especially popular but an 8 track format was also developed that squeezed even more out of the small tape width of the cassette.

We love these cassette formats and their accessibility helped start many musicians’ careers. Unfortunately one of the best 8 track machines, the Tascam 238 Syncaset also suffers from a common and frustrating problem that renders most of these machines useless over time, the dreaded direct drive capstan motor failure…

The 238 and other 8 track and high quality stereo tape decks, the 688 and 122 MkII and III, used a direct drive capstan motor for precise speed control and reduced speed variation or wow and flutter (w/f). The circuit that controls this motor fails in certain ways causing lack of speed control and in our case the capstan motor wizzing away at a crazy speed, not the 9.5 cm/sec that it should do.

PB160882 8 track cassette capstan motor tascam 238 syncaset

This here is the culprit  – you can see the attempted repairs which didn’t ultimately work.PB160872 233x300 8 track cassette capstan motor tascam 238 syncaset

One common failure is that the surface mount electrolytic capacitors fail or their capacitance changes to such an extent to cause speed problems. These can be changed for standard through hole caps but you do need to be very careful as the tracks are damaged very easily – good tools are essential.

The other point of failure in the circuit is the BA6304F SO16 IC – we even changed this but the motor still didn’t turn!

There was some suggestion from previous repairers that the grease at the end of the capstan flywheel hardens over time. increasing the friction and causing problems with the circuit.

This can become frustrating quickly, especially when you have a large archive of cassettes to digitise.

When we can’t repair we reluctantly do the next best thing and buy the whole replacement part but this is another exercise in frustration. Teac parts and Teac UK don’t have any european supply of this capstan motor (part no. 53700075-01) anymore as of November 2011. Interestingly about 6 months ago they did at around £60 GBP, then about 3 months ago they had one left at £160 GBP!

Lots of emails later to Teac US, Teac Canada and Teac Japan there seem to be a nice stock still on shelves somewhere and at reasonable prices UNTIL you ask them to ship to the UK when you discover they can’t do this and I’d need to go through Teac UK!!! I’m pretty persistent but I gave up finally even though some of the support staff tried to be pretty helpful.

We find support for older machines from the original manufacturers is not good generally and unreasonably expensive when you can find it. This is similar across audio and video, semi-pro and professional products. Some companies are easier to deal with and have better parts situation than other but stockpiling machines, parts, manuals and obsolete knowledge is the best course of action.

What we finally did that worked and was a good solution was purchase 3 Tascam 122 Mk III stereo cassette decks which use the same but a later revision of the capstan motor, (part no. 53700121-00).PB160868 300x235 8 track cassette capstan motor tascam 238 syncasetOne machine was donated for the cause and the capstan motor removed, modified and refitted in the 238. The 122 motor has a few factory extras, such as these resistors, shown here:

PB160877 300x265 8 track cassette capstan motor tascam 238 syncasetYou also need to solder / desolder the speed pads, to change the motor speed from 4.8 cm/s to 9.6 cm/s that the 238 needs to run at.

It’s also a good idea once you’ve got the capstan motor apart to clean the old grease from the seat, check the end float which can be adjusted using the screw shown on the left and apply new grease to the capstan end.

Put it all back together – be careful to solder the wires to the motor to the correct pads – they’re different on the 122 and test… Ours worked almost perfectly.

As the transport hadn’t been used for a while the reel motor would intermittently stop as if sensing the tape end. This can sometimes be loose counter belts but on the 238 it’s a digitial counter. We cleaned up the leaf switches on the transport top and also sprayed a small amount of deoxit into the inside of the reel motor. A bit more use and it finally worked to spec…

For 4 track and 8 track multitrack cassette transfer please contact us for more information.

 

 

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4 Responses to “8 track cassette capstan motor tascam 238 syncaset”

  1. Fran Flynn Says:

    I have restored several 122 mkII and mkIII decks. I have recapped the capstan motor and still noticed speed problems. What apparently happens is that when the surface mount electrolytics fail, they also deposit conductive electrolyte on to the PC board below. I have had success with cleaning the pc board very thoroughly after removing the surface mount capacitors before installing new caps. You can see evidence of this problem by simply breathing on the motor and noticing the speed change. The conductive material on the pc board is apparently sensitive to moisture. This could be planned obsolescence or bad design. The capacitors should have been tantalums in the first place, there would never be such a problem in that case.

  2. Nacho Says:

    FRAN FLYNN
    I’m working on a 122MKIII with speed problems. (plays too slow when cold, but returns gradually to almost normal speed when warmed, polarized capacitors have been replaced). My board was clean and looked fine, no leakage. I did try what you said: I breathed on the circuit…. it almost instantly speeded up. I blown and slowed it down again. WOW!! Now I have more clues on what to test

  3. Jess W. Regan Jr Says:

    I was looking at this page, dreading changing caps, when I tried something I never would’ve suspected. I adjusted the set screw on the back of the direct drive motor, (2nd picture, just visible behind the big black cap), and dang if it didn’t start running at the correct speed. Still makes a slight bit of noise, so maybe I’ll have to clean and oil the contact point between the capstan and the set screw, but I’ll be damned. It freakin’ works! Thank you!

  4. Steven Says:

    Hi, same trouble here with my 238, plays constant at I/2 speed. The correct speed pads are jumped. Interestingly when I also jump the 4.8 pads the speed goes too fast. There is something just above the big screw head in the 1st pic marked VRI that can be turned to affect speed slightly but not enough.

    @Jess – Sorry but I don’t see any big black cap on the 2nd pic so not sure which screw to turn. And does the motor have to be removed to get to it? Thanks.

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