Capstan motor for Technics RS-M245X cassette deck

hermhart

New Member
I have a Technics RS-M245X cassette deck which I purchased at Goodwill. It seemed to be playing cassettes well. However, I discovered that occasionally, about every minute or so, the speed would drop for a few seconds and then pick back up again. I assumed that seeing the capstan is more massive than it is for cheaper decks, that probably the drive belt was stretched. (I have a Technics turntable I got at a thrift shop that had that problem which was easily remedied by replacing the drive belt.) So I got a new belt, and using an online service manual and my ingenuity got it replaced. However, upon getting everything back together, now I find that the drive motor is dead. I thought maybe I had damaged something in the replacement process. However, there is voltage applied to the motor, but it doesn't turn. So that tells me that the problem is the motor itself. I thought maybe coincidentally, there was trouble with the belt AND the motor, which is possible. But my wife said, Well, maybe the trouble was the motor all along. And I thought, well maybe so. Maybe the voltage regulation circuitry was going out and then finally quite entirely. I read a thread somewhere where he had a similar motor whose regulation circuitry had burnt. He had just put in a resistive voltage drop, which sort of worked for him. So...

The motor is part number MMI-6A2LKPA. It looks as though Panasonic has had an equivalent part of number 330PPL3D9ONSD. It looks pretty grim trying to find one to buy online, at least at a reasonable price. So, here are my questions...
1. Where could I acquire this motor at a reasonable price?
2. Is it practical to rebuild the voltage regulation circuit for it? (I've worked a lot with voltage regulator circuits.)
3. Is there a broader issue that I'm not even asking?

Thanks
 
I have a Technics RS-M245X cassette deck which I purchased at Goodwill. It seemed to be playing cassettes well. However, I discovered that occasionally, about every minute or so, the speed would drop for a few seconds and then pick back up again. I assumed that seeing the capstan is more massive than it is for cheaper decks, that probably the drive belt was stretched. (I have a Technics turntable I got at a thrift shop that had that problem which was easily remedied by replacing the drive belt.) So I got a new belt, and using an online service manual and my ingenuity got it replaced. However, upon getting everything back together, now I find that the drive motor is dead. I thought maybe I had damaged something in the replacement process. However, there is voltage applied to the motor, but it doesn't turn. So that tells me that the problem is the motor itself. I thought maybe coincidentally, there was trouble with the belt AND the motor, which is possible. But my wife said, Well, maybe the trouble was the motor all along. And I thought, well maybe so. Maybe the voltage regulation circuitry was going out and then finally quite entirely. I read a thread somewhere where he had a similar motor whose regulation circuitry had burnt. He had just put in a resistive voltage drop, which sort of worked for him. So...

The motor is part number MMI-6A2LKPA. It looks as though Panasonic has had an equivalent part of number 330PPL3D9ONSD. It looks pretty grim trying to find one to buy online, at least at a reasonable price. So, here are my questions...
1. Where could I acquire this motor at a reasonable price?
2. Is it practical to rebuild the voltage regulation circuit for it? (I've worked a lot with voltage regulator circuits.)
3. Is there a broader issue that I'm not even asking?

Thanks

The circuit in the motor is the speed control "DC servo" circuit, it can not be replaced by a resistor. One important issue - on that deck (and other Technics decks with that mechanics) the case of the motor needs to be isolated as the motor terminals are connected to the ground and the negative supply line -14V, so a standard motor with a case internally connected to the "-" supply terminal would create a short circuit and damage the deck's power supply. You need a 12V CCW 2400 rpm DC motor with an internal DC Servo speed regulator AND an isolated case. I may find one for you - drop me a PM (private message). You will also need a test tape to adjust the motor so the tape travels at the right speed.

Cheers

Alex
 
Hi Alex
Just came upon this thread do you know if you can still source this motor MMI-6A2LKPA? I have a Technics RS-B10 Tape Deck that uses the same motor.
Cheers
Wombat
 
Wombat, you may be able to use a Mabuchi EG-510/500 depending on the rotation- is it CW or CCW? The thread you are replying to is over 5 years old.

I have an MMI-5A2L here and it's the same dimensions as a Mabuchi EG-500YD. The EG-510 (with the inbuilt servo) is about 10mm longer, but has the same mounting screw spacings and is 2400rpm CW with adjustment.

I've just checked the case on the Mabuchi and they are isolated.
 
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