How to unscrew Rega RB300 counterweight?

[magiccarpetride]

I'm trying to adjust my cartridge on the Rega RB300, but the counterweight does not budge. I've included the closeup photo of the counterweight -- seems like there is some kind of a screw in there but I have no idea how to get it to loosen. Help!

https://imgur.com/a/5S6Zt

[walpurgis]

Hard to tell from that photo, but it could be a hex socket grubscrew, in which case you'd need an allen key of the right size.

You should be able to unscrew the counterweight stub from the arm with the weight attached, that might make it easier to work on.

[karma67]

if you save the picture to your pc and blow it up it looks very much like an set screw so yes id say you need an allen key to undo it.

[Primalsea]

Yes it does indeed look like an hex grub screw, so an Allen key is needed. Be careful though as some people believe that you really have to tighten the grub screw down hard. This is not true and usually just an 1/8th turn after the bottom of the screw contacts the stub should be plenty.

[magiccarpetride]

Yes it does indeed look like an hex grub screw, so an Allen key is needed. Be careful though as some people believe that you really have to tighten the grub screw down hard. This is not true and usually just an 1/8th turn after the bottom of the screw contacts the stub should be plenty.

Thanks for your help guys, you were right, Allen key did the job!

[amati74(Artur)]

It's look like Allen key but is dirty inside. Probably you should use some deeply penetrating cleanser perhaps GT85
or maybe find something more delicate if you are worried about your tonearm.