|8TMOT - ADJ
Our universal adjustable speed motor and speed control board
was roughly one full year in development, and is the motor we
most commonly use due to its adaptability to almost any unit.
This motor is included with all Ford, Mopar, AMC and Wollensak
restorations, and is offered as a quality and reliability upgrade
on many home units for higher torque and less wow and flutter.
To replace a motor, we must first determine the DIRECTION OF ROTATION and REQUIRED RPM.
If your pulley and flywheel are on top, you will need a motor with CCW rotation. If the pulley
and flywheel are "upside down", you will need a motor with CW rotation. Then we figure RPM.
To determine required RPM:
If your motor still runs but speed is inconsistent, we have the apparatus to measure RPM and
simply measure the RPM while the speed is correct. If your motor is dead, we designed the
BFM-1 Motor Simulator and RPM Gauge which makes this a one minute procedure,
Occasionally I prefer a mental challenge, and have devised this formula to figure required RPM:
1. Determine capstan diameter. The capstan is the vertical steel post to the right of the playback
head. It will be either .25 (large) or .18 (small). Multiply this value by 3.14 to arrive at your
CAPSTAN CIRCUMFERENCE. Note that a cassette capstan will be much smaller than above.
2. Divide 3.75 (or 1.875 for cassette) by CAPSTAN CIRCUMFERENCE, then multiply
that result by 60. This will be your CAPSTAN RPM.
3. Divide FLYWHEEL DIAMETER by MOTOR PULLEY DIAMETER. Call this result X.
4. Multiply CAPSTAN RPM by X. This is your REQUIRED MOTOR RPM.
In about 75% of cases, we should arrive at something very close to 2000, 2460 or 3000 RPM. The vast
majority of 8 track motors operate at 2000 RPM, but not all. Keep in mind that actual RPM will usually
be 30-40 RPM lower once motor is installed and loaded down by the drive mechanism. In most cases,
RPM is correct "as is", but it is possible that internal adjustment of the centrifugal switch is necessary.
To save time, we often substitute an adjustable speed, tachometer controlled motor which is adaptable
to almost any machine. A new motor is INCLUDED with all Ford, Mopar, AMC and Wollensak restorations
and is considered a quality upgrade - outside of our flat rates - on most other 8 track machines. Below
are pictures and descriptions of the motors stocked and installed ONLY by Barry's 8 Track Repair.
|8TMOT - 1
2000 RPM CW or CCW rotation with internal pulse generator
Diameter 1.75" Length 1.95" 12V, 50 mA
Matshushita part # MYF-15AF3
|8TMOT - 2
2460 RPM CCW rotation with Fast Forward
Diameter 1.62" Length 1.80" 12V, 100 mA
Unknown manufacturer, part # 440417N
|8TMOT - 3
2400 RPM CCW rotation
Diameter 1.59 Length 1.48 12V, 100 mA
Audiovox type M4 for home and car units, part # 279-04
|8TMOT - 4
2000 RPM CCW rotation with Fast Forward
Diameter 1.80 Length 1.60 12V, 80 mA
With pulley, exact motor for AkaI CR-83D
|8TMOT - 5
3000 RPM CW rotation
Diameter 1.82 Length 1.90 12V, 50 mA with grooved pulley
|8TMOT - 6
2000 RPM CW rotation with Fast Forward Nippon part # NAM - 3A
Direct replacement for some Lloyd's, Realistic and other models.
|8TMOT - 7
2400 RPM CW rotation
Diameter 1.625 Length 1.50 12V, 80 mA Mitsumi M40A2-2S
|We Even Have Complete, NEW Transports
|Tips for perfect speed tweaking - non technician version
1. First, look for a speed adjustment. Some better units with onboard speed adjustments are Pioneer,
Wollensak, and some of the classic Delco 8 track machines. They're usually not labeled, but are almost
always the control closest to the motor. It never hurts to "adjust and return" an internal control; in fact,
it cleans them and eliminates noise from an old, oxidized internal connection.
2. A tighter belt will slow down the motor, but place more wear on the motor and capstan bearings.
Cheaper manufacturers generally used a specific belt tension to set the speed.
3. A larger diameter motor pulley will speed the machine up. Wrapping layers of tape around a
pulley can increase its diameter in tiny increments.
4. A larger diameter flywheel will slow the machine down. Tape can work here too (I've never done this!)
5. If you have access to a lathe, you can reduce the diameter of a pulley or flywheel.
|8TMOT - 8
3000 RPM CCW rotation
Diameter 1.81 Length 1.80 12V Matsushita Part # MYT-11KF
|8TMOT - 9
3000 RPM CCW rotation
Diameter 1.53 Length 1.96 Matsushita Part # MYT-15MF
Has slightly more torque than 8TMOT- 8, otherwise similar
|8TMOT - 10
xxxx RPM xxx rotation
Diameter x.xx Length x.xx Unknown mfr. part # NEXD198
|All 8 track motors have a shaft diameter of 2 mm (standard size)
|BARRY'S 8 TRACK REPAIR stocks more than 2000 NEW 8 track motors!
|To maintain my claim as the world's best-equipped 8 track repair facility, I have purchased the entire
known remaining world stock of new motors for 8 track machines. You won't find them anywhere else!
|Our Inventory of NEW 8 Track Motors
on all Ford,
|Call 928-533-9666 (Paying Repair Jobs ONLY)
|DO NOT CALL FOR BELTS, PARTS OR FREE REPAIR ADVICE!
|The World's Only Shop With 100's of NEW Motors
|4783 N. Glenrosa Circle
Prescott Valley, AZ 86314