Simple fix for sagging counterweight on Ortofon tonearms
When I acquired my RMG309 a nylon tie was wrapped to support the sagging counterweight due to a deteriorated rubber tube that decouples the counterweight from the rest of the tone arm assembly. Since I was restoring an SME 3009 that had the same problem I ordered an extra set of rubber decoupling tube which fits the Ortofon but was too soft to support the more massive counterweight. What is required is a harder type of rubber tubing available from an auto supply.
Fixing the problem is very simple. To disassemble, loosen set screw [1] to release the spring, set screw [2] to remove the counter weight and then carefully pull out the short aluminum tube [3]. Remove all the deteriorated rubber inside the short aluminum tube [3] as well as on the other end towards the gimbal bearing tower [6]. Using fine sandpaper sprayed with a burst of WD40 clean the short metal shaft [4] until it is smooth and shiny. This will later be force fit into the new rubber tube [5] which is a 1/4" OD and 1/8" ID rubber tubing approximately 1 3/8" long I found at a local auto supply for .75 cents a foot. I did not bother to crazy glue the rubber tubing since there was enough resistance in the fit.
This is how it looks after reassembly.
Hi - thanks for this helpful post.
ReplyDeleteI have the same issue with an RMA309 but I can't really get the short aluminum tube [3] out. I have removed both screws in the hole on the counterbalance [2] - but the rubber sleeve and the tube won't budge.
I don't want to damage anything, so I thought I'd get your advice first. Did you simply pull it out by force?
Regards,
Claus
When working with tonearms, I never use force. In my case the counterweight (2), short tube (3) and short metal shaft (4) fell out in one piece because the rubber was very dry.
DeleteI've always wondered if the metal shaft was permanently attached inside the bearing tower. I guess I'll never know. I rebuilt mine almost 20 years ago and holds its own compared to the '90s Japanese reissue RMG309i and Bokrand AB309.
I hope that helps!
JE
Thanks for your reply JE.
ReplyDeleteMine really won't budge. The rubber on mine is orange and appears to be thicker so perhaps it's just really sticking to the tube. Perhaps a little WD40 will help.
The rubber damper was also orange in mine. Cleaning up the residue was a pain. I used a solvent - paint thinner or maybe acetone?
Delete