Tascam 644 Capstan Flywheel question

[John Hodge]

Hoping someone here can tell me where this part goes. Evidently it fell out upon disassembly without my seeing where it came from or it's orientation. I do believe it is related to the capstan function...here's the pic:

 

[SkywaveTDR]

It is a spring to supply a slight back pressure to the flywheel to keep it from going back and forth within the play that is there. It goes on the flywheel capstan shaft before you insert it into the bearing.

 

[John Hodge]

Yes, I've now ascertained that, but exact physical placement is now my dilemma. There are two bearings, nothing but 'plastic' inserts it seems, upper and lower (top and bottom). I have it now placed on the bottom on the short shaft, with the two 'wings against the lower frame, the center with hole up, so it always exerts pressure against the capstan flywheel. Hard to paint this picture...

 

[SkywaveTDR]

Yes, I know. The parts have to be paid attention to when you take it apart otherwise looking at the mechanical break downs does not always give the answer. They have them also in Pioneer reel decks. The Teac bearing have a opposing magnet method instead. Some other cassette deck do not have all that much play so that the spring would not be needed.

 

[John Hodge]

I tried logic for what it's worth; if I placed on top it wouldn't act to brake anything. There are no 'circular' marks on either top or bottom of the flywheel so the "wings" did not drag there ever and even if they did, metal to metal, it would have worn the wings badly. That only leaves one option... I hope. It's back together and no obvious recording or playback problems detected.

 

[John Hodge]

SO MUCH FOR LOGIC...found the diagram for 488 and turns out pretty much identical placement/parts as my 644. here it is. The spring is #11. Still cant figure why it would be metal to metal contact!

 

[SkywaveTDR]

Hi John,
The logic of it all may be something only they can answer. In springs like this they exist to push a flywheel back so as to provide contact to a rear mounted thrust plate. If the spring is put on so it contact the flywheel that would be logical as the other way it would just be acting as a washer. The Japanese are never known for putting in an expensive stamped spring piece where they can get away with a cheap nylon washer. So it seem to me that the bent part of the spring makes contact to the flywheel- don't worry about metal to metal as the part does not move. The other way the spring fingers are sitting in mid air not doing anything.

 

[John Hodge]

Thanks, it's in now as best I could determine from the illustration. Thanks.