Final Resort
I have a DV1 set and yesterday the squelch woudn't work before that the signal meter at the bottom woudn''t work.
And after the squelch propblem the volume was playing up does anyone know what could be wrong with it?
If all else fails do a full reset. Before you do, backup all the things you can, Memories etc, as they will be wiped from the Radio (Not the backups on the SD Card so they can be restored afterwards). Just in case, after backing up to the SD Card, I would switch the DV1 off, remove the Card, put into a P.C. and save all the contents. You can put it back into the radio then before doing the reset.
How to do backups, what can be backed up, and how to do a full reset is explained in the Manual.
Very occasionally the AR-DV1 can have a 'nervous breakdown' which can cause very odd things to happen, so it is not necessarily a hardware failure issue.
Do NOT restore any of the backups yet. Try the radio and see if all is working correctly. If so, the Manual explains how to get your settings back, from the backups you created.
If that does not fix it, then sorry to say it will probably have to be physically repaired.
Good luck