Tutorial: Cleaning the motors on a Tascam 38/48/58

ckswartwood

New member
Hi Guys,

I was having some issues on a machine of mine (Tascam 38) where both reel were having issues. All issues listed below were resolved by completing the steps I have outlined.

Problems:
Slow Rewind
Slow Fast Forward
Bad Wow & Flutter / Modulation on playback
And when a majority of the tape was spooled to the take up reel, the playback would crawl along at about 1.5 ips

*Disclaimer: Please keep in mind, I am merely a tape enthusiast - Not a qualified technician. Take this advice at your own risk.
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Remove the Clamper Reel Hub from the machine

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Remove the three screws on the Table Assembly Reel and remove

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Loosen the screws on the Base Assembly Lifter and remove the lifter

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Desolder the motor wires from the PCB

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Remove the Heat Sink

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Transistor/s from the heat sink. (don't loose the plastic spacers beneath the transistors)

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Remove the Motor Mount Screws

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Remove the Motor Screws (front & back) to remove the motor from the machine

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At this point, you should be holding a marooned Reel Motor!

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Lets remove the brushes!
To do this gently unscrew the black inlet screws to expose a washer and the motor brush.

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Make sure you make note of the orientation that the brushes are placed in the motor, if you put them back in a different way, they will "re-wear" and clog up the motor again from new wearing and friction. (I use a sharpie marker to make a dot on the motor and a dot on the brush to match up. One dot on one brush, two dots for the other)

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You are now free to remove the two long bolts to get the caps of the motor off

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Great, We're in!
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Just to ensure I put everything back together properly, I put tape on the motor shroud to signify the direction in needs to be in. (Better safe then sorry!)

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Now, clean ALL of the black shedding and crap out from the motor covers, the shaft, the bearing, washer and the commutator (the bronze thing) Make sure to lubricate the bearings, better would be to completely remove the bearing for a more thorough job.

I use an old toothbrush and Q-Tips and 97% Isopropyl Alcohol to clean everything.

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I use a razor blade to clean the grooves of the commutator

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Here are some photos SweetBeats posted for a similar issue to illustrate a proper before and after. (Please remove these if I am breaking a rule - I didn't think SweetBeats would mind.)

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THATS IT! Take these steps in reverse to get your machine back together.
I really hope this will help some people out with their own machines! After I complete these steps, my motors were quiet, smooth and FAST AS HELL!

Have fun and be safe!

ck
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Bearings

Do the motors bearings require a bearing puller/extractor to remove, or are they readily removable without additional tools??

-Mike
 
they should come out easily, try heating them up with a hair dryer and gloves (so you don't burn yourself). One more thing, don't use alcohol on the bearings, that will ruin them, the alcohol is for the metal copper contacts. You can replace the bearings if you want too, they can be found online, if you do, use ABEC 3 or higher bearings (size accuracy spec).
 
Tascam BR-20

Thank you for the response!!

I have a BR-20 that is noisey on FF and RW. Play works smoothly. I have thoroughly cleaned and relubed the machine, so the bearings are suspect.

I will disassemble the motors and post my findings here.

Thanks!!
 
it can be other things. the BR-20 is not that old, if it has seen a rough life you may have this issue it all depends on how much use the machine has had. You can look up the serial number in the back, it will tell you the year at least. That combined with the wear on the tape guides and heads can give you a rough idea of how worn the machine is. What is the noise like ? can you post a video ?it maybe something else. I wouldn't disassemble the motors before checking other stuff like brakes or any other part rubbing somewhere that maybe causing the noise.
 
Yes, that might be true. I purchased this BR-20 about 3 years ago locally (Mexico) for about US$300.00 which I thought was rather a great price. Unfortunately, the serial number and other TASCAM stickers on the back are gone.

The heads were misaligned, but I managed to align them with a Mac software osc and a test tone tape I made on a Tascam 32 which is pretty much on the money, although I need to purchase a MRL tape to get them spot on - but I guess it's a close match for now.

The noise seems like a grinding, winding noise, but only happens during FF and RW, even with no tape.

I opened her up some time ago and did a thorough cleaning and lube job. The heads are about 95% good or better, along with the tape guides. They hardly seem worn, maybe because of the 3 3/4 - 7 1/2 ips conversion on the machine.

I have another BR-20 which is dead quiet, as is the Tascam 32.

I plan on re-converting the slower speed machine to normal speed. I already changed the resistor on the servo control board, and can't see any difference between both BR-20s servo boards, so the difference must be someplace else.

The previous owner managed to bring the deck to 15ips (simply changing the resistor), but that's because the front panel speed control switch board was disconnected (wires cut). I replaced the wires on the board and speed dropped again to slow. So I guess I have to inspect that board carefully.

Anyways, the recorder is still packed as I have recently moved, but I'll get her out of the box in about 2 or 3 days and I'll get back with any findings.

Thanks!
 
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