Sunday, July 8, 2012

Ortofon RMG309 fix


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.