Sony DTC 690, DAT, reel motor problem

[Nigel Cook]

The right voltage to this motor but it is lacking torque. Turning the
"torque control" pot to maximum (upping volttage )improves things but not a
cure.
On retraction of the tape into the cassete, the motor is sluggish to respond
so the sliding guides are retracting before the tape is tensioned leaving a
loop of loose tape for a short while before total retraction,so not a brake
problem..
FF and REW are erratic/sluggish. Anyone know ,been here before, if it is
likely a bearing problem. Voltage and current seem correct to the motor and
it always starts, eventually, so not a shorted bit of rotor coils

e-mail (removing .....) diverse2@tcp.co.u.....k
electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse

Nigel,Diverse Devices,Southampton,England

 

[Michael]

In article <fYacnfU_27ma4u2iXTWJkA@tcp.co.uk>, "Nigel Cook"
<diverse2@tcp.co.antispam.uk> wrote:

The right voltage to this motor but it is lacking torque...

Sony has had this problem with reel motors in many of their machines,
including DATs and camcorders. The only fix I know of is a new motor. I
think the permanent magnets get somewhat demagnetized over time, but
anyone can feel free to correct me on that.

By the way, I once owned a DTC-690, and I wouldn't recommend putting much
money into one. They are very poorly made and have a lot of problems,
especially tape transport problems. They sound good when they work,
though. There was an update kit that fixed some of the transport problems,
so maybe yours has it installed, in which case it might work OK. I hated
mine, though.

 

[Nigel Cook]

"Michael" <me@nomorespam.com> wrote in message
news:me-2409032257470001@192.168.0.113...

In article <fYacnfU_27ma4u2iXTWJkA@tcp.co.uk>, "Nigel Cook"
diverse2@tcp.co.antispam.uk> wrote:

The right voltage to this motor but it is lacking torque...

Sony has had this problem with reel motors in many of their machines,
including DATs and camcorders. The only fix I know of is a new motor. I
think the permanent magnets get somewhat demagnetized over time, but
anyone can feel free to correct me on that.

By the way, I once owned a DTC-690, and I wouldn't recommend putting much
money into one. They are very poorly made and have a lot of problems,
especially tape transport problems. They sound good when they work,
though. There was an update kit that fixed some of the transport problems,
so maybe yours has it installed, in which case it might work OK. I hated
mine, though.

Many thanks for the input. I could only think of the bearing problem
often seen on capatan spindles where there is just too much play
and at certain speeds brakes itself. I never thought of loss
of magnetisation. I agree about the mechanics ,while in there ,
i made a filler piece to retract the take-up side sliding
guide fully up against its tape-retracted position.