By popular request (really, I got quite a few emails about this!...;-), I finally completed my Beogram DC motor restoration video! It demon...
Thursday, December 7, 2017
Beogram 4000: Restoration of the AC Motor and Replacement of the Reservoir and Motor Capacitors
After restoring the PCBs of the Beogram 4000 that is currently on my bench it was time to look after the reservoir and motor capacitors, and the AC motor itself. This shows the capacitor and motor section of the deck in original condition:
I started removing the old cans and found that the big ones had started leaking:
So it was definitely high time to get this done. This shows the capacitor bay after removing them:
I also removed the motor (this was a good moment since its leads were already unsoldered from the capacitors):
The motor is held together by threaded rivets. If one wants to open the motor to re-lubricate the bearings, these rivets need to be drilled out. This is how the motor looked like after returning from my drill press:
I opened it up
A very simple yet elegant construction! Made in Switzerland...those were the days...;-).
This is a close up of the rotor with everything that sticks on the shaft:
I immersed the two halves of the motor housing with the bearings in oil (it seems there is no obvious way to get the bearings out without doing major damage) and pulled a vacuum to draw oil into the bearings.
I have actually at this point no evidence that these bearings are indeed Oilite bearings. It seems no significant bubbles form after the vacuum is up. But the treatment has so far permanently cured all motors that were knocking, so I am continuing doing it....
While the bearings were in the oil I installed my capacitor replacement assembly:
It consists of a 3D printed plastic shell that holds the new capacitors in place, and that fits into the mounting strap of the original capacitor assembly:
The motor was reinstalled using two 3D printed 'nut arresters' that are used to replace the drilled out threaded rivets, that allowed to adjust the tilt of the motor relative to the platter axis (this allows to adjust the height at which the belt sits on the platter):
These plastic parts hold the M3 nuts in place that one can adjust the tilt screws agains the motor housing:
I also usually replace the original slotted adjustment screws with modern stainless hex socket head bolts. They make the tilt adjustment so much more straight forward when the platter is installed since one can use a ball end hex screwdriver at an angle turning them while the platter is rotating.
Unfortunately, in the meantime I had to realize that the MMC cartridge mount of this Beogram has the (frequently found) cracked MMC cartridge mount, so the next step is to replace it with one of my (you guessed it!...;-) 3D printed replacements.