Are all Servo motors the same? please help me!

Plaguedog

New member
i really, really want to get my mt8x fixed. will a servo motor from another 4track/8track work? please somebody tell me! i don't care if you make it up, i NEED advice!!!!
 
Are you SURE it's a SERVO motor?

Is it belt drive or direct drive? Have you opened up the unit to inspect it?

Belt drive units are usually the more simple DC motors, (not servo). Also, when drive function fails, it's usually the BELT more often than the motor.

Direct Drive units are usually servo motors, which is quite different from belt drive.

Most Tascam Portastudios and Syncasets are belt drive, DC motors, with the exception of the most sophisticated units: the 644, 688 & 238, which have built-in plug-compatible Sync function.

The 238 I'm positive is a Direct Drive Servo motor, as I've just had the opportunity to have one replaced. The 644 & 688 I'm ASSUMING are also Direct Drive Servo motors, which leaves the possibility open that I'm MISTAKEN,... in which case, some more knowledgable member will eventually come along and correct me.

[OT], the Tascam 388 is a BELT drive unit, that uses SERVO function in the tension arms, PLUS a "tach wheel", which in effect achieves the same Sync capability as a Direct Drive servo-type unit. The Servo is used for that spot-on accuracy, that shuttles tape to an accurate set point, and stops on a dime. A non-servo return-to-zero, like on the Tascam 38, will zoom past zero, then reverse,... past zero again, then reverse, and in smaller increments, rock back & forth till it settles on zero. That's NON servo accuracy for'ya.

The Yamaha MT8X, I have no direct knowledge of. You could tell me more. Maybe we've been throwing the term "servo" around too loosely, but that's all I know of the subject. I know what I know, but YMMV. Maybe if you could fill in supporting details, eh?

In most cases, a qualified repair tech might an answer, with maybe YAMAHA FACTORY SERVICE being the best alternative.

Good Luck.
 
Nay,... belt drive.

I checked the MT8X manual, and Direct Drive is not mentioned. I'd venture to say, that the MT8X is likely a belt drive capstan. Granted, I'll give you the point, that the motor's listed as "DC Servo" motor. Servo may not be the main issue, as it pertains to this question. It may not need a motor, at all.

[OT] The MT8X is a virtual clone of the 488mkII, which is indeed belt drive.

[OT] After some thought, I'll retract the statement above, that AFAIK the 644 and 688 are Direct Drive. To the best of my knowledge, the Tascam 644 and 688 were belt drive Portastudios. Most of the locate functions on these Portastudios were done with "tach wheel" technology, alone. [Not Direct Drive transport].

My first recommendation would be to open the MT8X unit up, and check for coherency of the drive belt, and the spinning function of the motor. If you have already done so, and verified DD or otherwise, then I beg your pardon, please.

/DA
 
Ps:...

The Tascam 488 manual lists the motors as "DC Servo" motors, and the unit is indeed belt drive. The Yamaha MT8X and the Tascam 488 would have used viturally the same tape transport.

Opening the MT8X unit up, and getting a first person view of the cassette transport mechanics, would forward your issue, quite a bit. I'd say, verify and/or replace the drive belt.

If I'm entirely mistaken, or off base on this one, again, I beg your pardon.
 
Hi,
Can anyone share the Yamaha part #s for the motor and belt? I recently took my MT8X apart and it is belt driven. If there were a motor with the same physical dimensions and electrical specs and different rpms, it would work fine. The tape machine would likely run at a different speed, which be okay unless you were trying to run a tape recorded on your MT8X on another machine.
 
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