@esky
Honestly it is not a great arm. Only really suitable for high compliance cartridges, unless you have the 3009R which has a stainless steel arm tube and has a higher effective mass.
My advice would be to simply re-solder all the connections - you need to remove all the old solder first and then re-solder with new solder. You might find that the earthing is the issue - there is an earth wire running from the 4 pin bracket to the arm-tube ( inside ) that may be broken - you can use a multimeter to check this.
The other possibility is a dicky joint in the cable from arm to phono - you can test this by using a multimeter to test continuity by removing the arm cable and wriggling the connectors at each end with a multimeter checking continuity.
Any technician should be able to do this in a few minutes if you can’t do it yourself.
A good source for technicians is to check out the professional sound companies who supply DJ equipment - they have tech’s to maintain DJ decks etc and usually are very competent.
Another simple test to see if it is earthing is to run a wire from your phono earth and use the other end as a probe to touch the arm at various points and see if the hum disappears.
