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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
I am close to finishing restoring a Beogram 4004.
I have fixed the usual arm failing to lower problem (stuck pivot on horizontal lever) but now see that when the arm is lifted there is no damping - it bounces up and down (away from the record) a couple of times before settling.
I have checked the brass damper and that appears to be designed to provide damping only when lowering the arm.
It looks like the right hand spring is actually providing the lifting force, when the solenoid releases. From photos it appears the spring is the correct size
Is there anything in the linkage that is intended to damp the arm upward movement on these turntables?
I have a 5500 and an 8002 and both of them raise the arm quickly but smoothly without any bouncing.
Thank you for any advice
Hi Dave and others,
I have the same problem and just started searching the forum for ideas on what may be causing this. I would appreciate any advice you or other may have.
Thanks
Hi and a happy new year
To both two questions
1. Is your MMC cartrigde mounted?
2. Did you aligne the counterweight to zero and after that adjust the tracking force to around 1,2 grams?
two questions which might be silly but......
Just saw that the arm is lifted.
Best regards
Christian
Yes, the cartridge is mounted and the tracking weight is set.
Looking more at it last night, I actually think the problem is that I used a too viscous silicone grease for the damper after I cleaned it. The solenoid/spring appears not to push the piston all the way in when lifting. Once that is off, much doesn't work right. I checked posts on the specifications of that grease. Someone mentioned a Dow Corning 200 Fluid which I believe is much less viscous than. the generic silicone grease I used. Does anybody have recommendation on the right grease/oil to use for the damper?
Thanks, Per
Hi Per
What you already investigated makes sense.
Clean out the grease and just apply a little bit vaseline or silicone grease which is used for O-rings, adjust the damper with the "airvalve" on the top of the damper.
Look that the inner valve of the piston is working.
This valve opens when the relais is of and the spring loaded arm is pushing the damper in.
This is why the tonearm is lowered slow and lifted quick
Take a look at Beolovers video for more details:
https://www.youtube.com/watch?v=IxIxHb8sZdg
Good luck
I cleaned everything again (second time) and applied a less viscous silicone oil (50 cSt which is similar to 10W motor oil in viscosity) instead of the heavier silicon grease I had use before (which I learned is 5000 cSt). I also checked that the inner valve in the piston works as intended. The damper seems to work very smoothly now and easily when the air valve in the back is opened.
I should say that the BG did not have much dirt when I cleaned it first after buying it a month or so ago. Also, there are clear signs of someone having worked on it before (some of them not good signs like solder iron having done slight damage to some wires).
When fully assembled and the main air valve on the damper is opened, all works as you would expect - compressing and extended the damper fully, but of course the arms lowers very quickly then. As I increase the damper effect by screwing in the valve screw, the arm lowering slows as intended. However, before I can get to the ~1s lowering time the spring is not able to operate the levers and the motion will stop at the point when the piston rod hits the vertical lever and experiences more resistance. The solenoid pushes the first arm that it is connected to all the way down rapidly and holds there, but the spring, which is responsible for pulling the piston out of the damper and lowering the arm, does not pull the sliding arm next to the solenoid all the way with it. The vertical lever connecting to the v-groove and the arm seems to have the right springiness and resistance - at least it is very close from what I can gage - and there is no sticking. A very slight push with my finger makes the spring, which is responsible for pulling the piston out of the damper and lowering the arm, contract fully and complete the movement. It mostly looks like the spring has weakened. Has others experienced that problem? Does anybody know what the specifications of that spring is and how to evaluate its elasticity (like a certain extension with a given weight other other method)?
Thanks,Per
NB: Since this is veering off topic from the title and original question of this tread, I am posting these questions in a new tread with the link below. You can also search for my user name "ski4ever". Please answer there. Thanks!
https://archivedforum2.beoworld.org/forums/t/45358.aspx