This is a follow up to my recent post about the redesigned Beogram Commander remote control board, which now works in both (DC-motor) Beogr...
Tuesday, April 12, 2016
Beogram 4002 (5513): Rebuilding the Arm Lowering and Tracking Systems
I started restoring the Beogram 4002 (5513) that I recently gave a first checkup. As usual, I first did the arm lowering and tracking systems since without them up to spec further testing and rebuilding of the other Beogram functions is difficult. Here are a few impressions of my process. This video shows how to rebuild the tone arm mechanism in detail. This picture shows the mechanism assembled:
First, I removed the damper and linkages for cleaning and lubrication:
This shows the removed parts:
All parts were in good original condition and so all I had to do was lubricate everything and put it back together. Then it was time to lubricate the pivot point of the damper to arm linkage. For that one has to take out the sensor arm:
This shows the linkage removed:
This video shows how to get to the linkage and re-lubricate it. After lubricating the shaft, it was time to put the sensor arm back in and to adjust the arms to be parallel and orthogonal to the carriage rods:
After this was accomplished, I replaced the original tracking sensor light source with one of my LED based replacements. This shows the original part in place:
And with the replacement in place:
I recently had proper circuit boards manufactured for this part, so it looks now quite professional. This shows it from the light source side in comparison with the original part.
These parts are available to other enthusiasts. Just send me an email or use the contact form on the right and I can send you one of these:
Whenever the tracking sensor light source is replaced the tracking feedback sensitivity needs to be re-calibrated. There is a video that shows the tracking sensor adjustment procedure in detail. I put on my least liked record and a dented MMC20EN from a not-so-great ebay deal and did the adjustment to get about 2 turns of the platter before the carriage servo starts kicking in:
So far so good...the tonearm is now behaving well. On to the motor and the electronics.