Beocord 9000: Exchanging the Rubber Parts in the Tape Mechanism

I made some more progress with the Beocord 9000 that I am restoring right now. I recently received the rubber 'tires' for the idler wheels in the tape drive mechanism and so I set out to install them. The reason I went ahead to do this was that the deck would not rewind properly. At the end of the rewinding process, when the power to the motor is reduced by the microcontroller the winding process became very slow and, depending on the particular tape, it also stopped in some cases. Of course this was not acceptable, so I looked around, and what came up on Beoworld.org suggested that the idler wheel rubber tires can harden over time reducing the friction and hence the transport becomes slow.

It turned out later, after I took the mechanism apart that a previous 'repair' effort on the mechanism bent an important friction pad, which in effect caused the problem. Well, now we have new idler wheel tires in the drive but also a straightened out tab that functions properly again. I think it is part of any decent restoration to refresh the rubber for long term stability, so I do not think the replacement was a useless effort. Anyway, I made a video about the replacement of these idler wheel tires (that can be obtained from Dillen of Beoworld.org...what would we do without him!!...;-). Here is the video (pay attention to the part where I discuss the bent pad - this can happen very easily if the drive is assembled without knowing about this issue):

It is worthwhile pointing out that I had a couple of issues during the rebuilding of the tape drive:

1) The plastic fixture of the clutch had a crack. This seems to be a standard issue with these drives. There are several posts on Beoworld about it and how to fix it with sections of brass pipe. I went a different route, since I did not like that one has to take the clutch apart for fitting the brass segments. My solution was to print a two-part ABS plastic sleeve that I then glued together around the part using Acetone-printer filament slurry. I will make a separate post about this in the near future.

2) After I plugged the drive back into the Beocord, it behaved erratically. When I pressed 'play', for example, it would go on 'fast forward' instead, rewinding ceased to work altogether. It turned out that pulling the plug of the ribbon cable that goes into the microcontroller board caused the board-mounted header to crack several solder points, and that caused intermittent behavior. To I desoldered them, and that fixed everything. This shows the header with the cracks. If you look closely you can see the ring shaped hairline crack around the top pin:

I added some flux and solder to the points and that fixed the problem:

After this I tested the drive, and it performed flawlessly. I measured the fast forward and reverse times for a C90 Maxwell tape:

FFD: 1:44 min with the motor power reduction coming on at about 1:37 min

FRV: 1:40 min; motor power reduction at 1:33 min

The spec from the manual is C60 takes 70 sec in either direction. So I think we are pretty close at ~100 sec for a C90. You guessed it: I do not own C60 tape...never understood their purpose...;-)

What is left to do is to get the rubber pinch roller rebuilt by Terry Witt. While it still performs o.k. it shows a bulging cracked surface, i.e. needs to be fixed to make this a 'full' restoration. Here is a picture: