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Wednesday, June 21, 2017

Beogram 4002 Type 5513: Fit and Finish Rework

These Beogram 4002 restoration projects are rewarding and fun but they often require going back over things multiple times. I had this Beogram playing really well and once the trim and deck pieces were fitted, this deck would be done. The problem was I wasn't happy with the resulting fit of some of the pieces.

The tonearm cover didn't fit quite right. you can see in this picture that the tonearm cover is on all the way but sits slightly crooked. If you look at the tonearm cover between the fixed arm and tonearm carefully you can see that the center divider is not evenly spaced.

This picture shows the tonearm cover problem from head-on view. You can also see that the deck trim doesn't line up well. There is too big of a gap between the two deck panels for my liking.

Another problem cropped up during this final fit check. The record tracking started to hang up and not track. I had to remove all of the deck trim to investigate. At first I thought it was related to the tonearm cover but the problem remained even with the cover removed.

I exercised the tonearm travel a bunch of times to see if I could spot a problem. To my surprise I could visually see the tangential drive motor and screw slow down during fast forward travel near the center of the platter. This was puzzling so I immediately rechecked the drive screw lubrication and the belt. I finally discovered the problem was with the new drive pulley.

Since starting this project our drive pulley supplier, Nick (in the UK), sent me a new re-designed aluminum pulley for the Beogram 4002 turntables. Here are some pictures of the pulleys for the Beogram 4002.

The new, version 2 pulley is much closer to the original pulley. It has the four holes around the center hole like the original, plastic pulley. Those are for certain Beogram 4002 versions that had an optical sensor attached. The new pulley is lighter weight than the version 1 pulley.

As soon as I swapped out the drive pulley to use the version 2 model the tracking problems went away. Looks like I will be ordering a few of these new pulleys going forward.

To address the arm cover fit I ended up going through all of the fixed arm and tonearm alignment procedures again. This time I added the fit of the tonearm cover to the adjustment checks (before locking down the arm positions).

To fix the deck panel gap problem I had to go through all of the guide washer adjustments again as well as check the posts on the leaf springs. It took a good number of iterations to get the fit right.

Here are the final results of the rework. The deck lid seam looks good, tonearm cover is straight and the Beogram is back to full functional play testing again.

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