As best as I can tell, it would be:
ID - ~8-8.5m
OD - ~11-12.5m
Thickness (height when laid flat) - ~3mm
Can anyone confirm?
Can anyone point me to a supplier who might have something close?
This is the closest I could find-
Thickness(THK) = 3.6 mm (mm) Measurements in millimeters Metric system
webspareparts.com
Thank you
Hi all, re: HK CD-401 -
Intro:
Long story short - I have a CD-401, bought some months ago from a dishonest Audio Lab pro seller (he sells descent gear though) on line and paid him in advance. Many issues NOT disclosed, including this PB, FF, RW present on picking up demo. He even blamed me made it to stop after I touched the faceplate,
We HiFi'ers all know this must be from belt or wheel failure. He asked more dollars to fix it. I denied and took it home as is. I have been busy since, but bought some belts, just to prepare for fixing it myself.
(A) Belts -
With the new belts in hand and over many after-work long nights studying this machine, I determined it a difficult box, not designed for diy repair. When I was about to give up, I found some ways to remove the motors for putting on the main and spool new belts, but nothing changed after.
(B) Wheels and Idlers -
I then looked at the tranmission parts, in different nights and with different resuslts from each. I hope my experience can help and benefits whoever needs it.
Here we go, in summary form:
(1) on checking the intermediate (white) wheel and tyre, the tyre (belt) disintegrated into pieces.
(2) replaced it with an O-ring that I have in hand, but its too narrow, the final (black) wheel missed it and was too thick.
(3) added one more O-ring to make it wider for contact surface, worked, but the thickness was apparently a problem. They squeezed and pushed the black wheel tyre up, especially with FF and RW speed. I was hoping the black wheel tyre to run in the groove between two O-rings, that didn't happen because the black wheel tyre is like a flat belt riding on both O-rings.. (when belts and that tyre gave up, it was a sign of time the other rubber parts reached the end of their lives).
(4) When pressure built up, the clutch hub behind the white wheel tyre disengaged, and kept slipping. I believe it acutally slipped before I noticed or before I put on O-rings.
(5) I also tried with pvc shrink tube, 1 ring, 2 rings (1 over the other), they worked briefly. Afterall, pvc tube for tyre can not survive the service of playing.
(6) Removed the very tiny retaining washer....(note - in my case, this washer broke, and flied away two time. luckily and finally found it back to hold).
Findings:
(a) the clutch hub case had some kind of felt for friction,
(b) the white plate carrying the said white wheel per #1 above has some hairline concentric grooves ,
(c) other parts consist of a black coupling tube-ring and a disc with a brass cross.,
(d) I thought this cross was for a rotation motion *sensor next to the spool belt motor, but proved wrong. No idea what it is for except as a sub-set friction part. ( * a 2SC2320 transistor).
(e) no idea what to do next, how to rejouvenize or to replace the felt to generate friction and how much friction is actually needed,
(f) I chose to take a "non-damaging" option (no matter what, the felt has be fixed or to go, the grooved plate can be cleaned with white alcohol or nail tint remover if needed). -
(i) applied glue spray over the felt, and on the grooved plate, let them dry for 2-1/2 days, (note: all parts must not be seized together. they need to slip to avoid breaking the tape when tension arises).
(ii) put them back, bingo. I got back the friction. May not be enough or too much, but it works, at least I got back the motion from spool motor.
(g) now, back to the tyre:
(i) measured the white wheel, dia. is like 9mm x 11 mm with tyre. (unfortunately no such flat-belt in the market for diyers),
(ii) rubber tubes of 9x11 or 8.5x11, don't have any handy and don't know where to buy,
(iii) where I was jotting down the shape and size ..... with a pencil and ball pen, I noted they have a "rubber" collar on each (i suppose they are soft pvc),
(iv) no harm trying, I pulled them out, cut a ring from the section that looked near/alike,
(v) bingo, another bingo, it worked. this tyre must NOT be too thick,
(vi) privsio - it worked but not the best of what I expected,
(a) both collars are not real or artificial rubber, pvc wouldn't last long
(b) neither can provide me with consistent performance, but the tyre ring on deck works for couple of hours now, and yes, the deck had 3-4 time occassional stops, but could continue to "play" when pressed again,
(c) so far no tape chewing on Play, and FF, RW both work.
CONCLUSION:
These are the areas to heal.
I will keep it to run as is until I can find the rubber tyre, and hopefully, for the black wheel as well.
