capstan belt

Repair Teac A3440 4 track Multitrack Reel to Reel

The Teac A3440 is a classic reel to reel tape recorder from the late 1970’s, early 80’s significant in that you could use it to make 4 track multitrack recordings at 15 inches per second, the professional tape recording speed. At the time there was precious little else around at the price to do this so this machine was perfect for small bands and studios who didn’t have the wallet busting amounts needed to buy a larger format 16 or 24 track recorder.

While the A3440 isn’t the last word in high quality analogue recording it has had some significant users in the past none less than Lee Perry who’d used the earlier but similar A3340 on his Heart of the Congos album.

the problems

This machine didn’t initially look heavily used, the heads had little wear but it hadn’t been used in a long while and there was a heavy build up of tape residue on the whole tape path. The capstan was very dirty and i these cases xylene is a more effective cleaner than IPA but don’t get it anywhere near plastic!

This A3340 powered up but the right hand tension arm was hanging at an odd angle and it wouldn’t play or wind.

Time to take it apart – the fake wood sides and rear panels get removed and it’s pretty easy to see what one of the problems is.

teac-a3440 sticky broken capstan belt

A very nasty ‘melted’ rubber capstan belt that took a fair while to scrape and clean off with IPA.

A new belt has purchased online – Teac parts in the UK are a big pain to get hold of through the official channels and I’ve given up contacting them unless I’m desperate for a part I can’t find anywhere else.

The other lack of drive was caused by broken micro switches. When the right hand tension arm is moved up, two micro switches behind the front panel switch power on for the capstan and reel motors. As this arm can get a los of use / abuse it’s common for the micro switches to crack. Both on this example were broken as was the small plastic piece that stops the arm moving too far down.

the repairs

To replace the capstan belt:-

  1. Remove both screws holding the capstan flywheel against the front panel.
  2. Make sure the flywheel is cleaned of all old belt debris.
  3. Make sure the motor wheel is cleaned of all old belt debris.
  4. Refit new belt over small motor wheel, then flywheel.
  5. Replace bracket remove in part 1, making sure you’ve cleaned off the old grease and regreased where the end of the capstan shaft can run.

Although not essential I took the opportunity to remove the whole capstan shaft, clean, check for wear and reoil before putting back. If you do this you will need to reset the endfloat though.

microswitches

teac a-3440 capstan motor micro switch

It’s not possible or worthwhile trying to repair the microswitches as the modern equivalent that fits perfectly is very cheap. Two were purchased from Farnell and replacement is just a case of:

  1. Unscrew and move away the control PCB to get more space
  2. Make a note of or photograph wiring connections for switches.
  3. Unscrew and carefully desolder the existing microswitches.
  4. Connect wires and solder the new switches in.

The arm end stop was repaired easily with strong super glue and after many hours is still holding.

is it working?

In a word, kind of! The belt and microswitches got the deck and transport moving. It will pull tape and make a noise which is great but an annoying intermittent problem started to appear after some initial testing.

When play or wind are selected, large solenoids clunk and release the reel brakes and move the pinch wheel. This was working BUT occassionally and only in play the right reel brake solenoid didn’t move, leaving the brake on, causing the tape speed to slow, back tension to increase and wow to go crazy!

See our next post for the repair of this problem…

Posted by greatbear in Audio Tape, 5 comments

Replace Tascam BR 20 Capstan Belt

We have two of these excellent machines in addition to our Sony APR 5003 and Studer A80’s. The Tascam BR-20 was Tascam’s last and top of the range 1/4 inch reel to reel tape machine and available in two track stereo and stereo with centre timecode option.

The capstan drive in the BR20 is belt driven by a wide belt. Both belts in our machines looked OK but we’ve replaced all roller bearings, belts and pinch rollers in both of our machines anyway as a matter of course. These parts are still available from Teac UK via Acoustic Services on 01-844-347600.

Below is a simple explanation of how to change the capstan belt.

Tascam / Teac BR 20 rear panel removed

  1. Unplug machine from mains power and move to a strong stable base.
  2. Remove cross head screws from the rear panel and lift plate off. Depending on the type of plug in your country you may not be able to remove it completely.
  3. You’ll now be able to see the capstan motor and it’s control board attached to it.
  4. Remove the 4 cross head screws and gently lift the analogue audio output board away from the machine as in the picture above.
  5. We now need to remove the whole capstan motor assembly with the control board still attached. Remove the 4 cross head screws right at the front of the assembly, NOT the six nearest to you when looking at this image. 
  6. Carefully unclip the 4 cable connectors from the motor control board. The other connector cannot be removed from the board and must be removed where it connects to the other board.Tascam BR 20 capstan motor board with cables removed
  7. The whole assembly can now be lifted out from the machine. Be careful to not snag any cables and remember to unclip the black cable ties.
  8. You’ll now be able to unclip the control board from the assembly by carefully compressing the black clips with some needle nose pliers.
    Tascam BR 20 capstan motor board unclipped from assembly
  9. Now remove the six cross head screws holding the capstan motor assembly together. This is the only way to remove and refit the capstan belt. There’s not enough room to do it any other way!
  10. Now you can remove the old belt and capstan shaft. It’s a good idea to clean the capstan with IPA where the old belt has run and reapply a little grease to the bearing end of the capstan.
  11. Fit your new belt and reassembly is the reverse of dissasembly! Be careful though to not drop the screws into regions you can’t get them out of – luckily there aren’t that many on this machine but a long magnetic screwdriver is very useful.. just don’t get it anywhere near the headblock and heads!
    New Teac capstan belt for Tascam BR20 reel to reel tape machine
Posted by greatbear in Audio Tape, quarter inch tape, tape machines, 2 comments

Teac C-3x capstan belt

I recently ordered and replaced the capstan and counter belt on this cassette deck. These parts are easily available from Fred Marrs who sells a huge range of correctly sized replacement belts through his eBay shop. He has even gone to the lengths of remanufacturing the Nakamichi OC 8096 capstan belt to the correct specs.

This Teac machine is a really nice 3 head cassette deck, built like a tank, and very similar if not identical to the original Tascam 122. I don’t use this deck for normal cassette transfers as I feel my Nakamichi decks generally sound better but this is one of the few decks that can record and playback at double the normal speed so it’s reserved for these transfers and as a backup.

The transport is quick and easy to remove and the belt was easy once the capstan had been removed – this was also greased and oiled a little too.

Teac C-3x transport removed

Teac C-3x transport removed

Teac C-3x capstan motor with new belt

Everything went well until  I tested it with an old tape – It would play for a few seconds then the take up reel would stop letting tape get pulled around the pinch wheel, well and truly chewed!  It looked like the rubber drive wheel that the reel motor works against has perished at one point or slips. I also noticed that the little rubber sleeves that act as brakes on the reels have perished too. I’m going to have to get it all apart again to fix this – see below for more soon..

Oh and here’s a the service manual for free, so you don’t have to get fleeced by an eBay seller who’s downloaded a load of free manuals.

Teac C-3x Service Manual

Posted by greatbear in Audio Tape, Video Tape, 13 comments