The classic Dual 601 turntable is perhaps not as well-known as contemporaries by Thorens and Rega, but they are very good decks.
This particular Dual 601 had a very common problem, whereby the tone-arm would not return properly at the end of a record. Automatic decks such as the 601 typically have complex mechanisms to return the tonearm to its resting point at the end of a side.
In this case and with Dual decks, a small rubber ‘button’ wears out and perishes, falling off a small lever, causing the arm not to grabbed by the return mechanism and therefore to not return. I’ve described a similar repair on another Dual 601 here.
The problem is fairly easily fixed, once you know what to look for and how to repair it. I have a few pics here if the deck in various stages of disassembly. Once inside, there are numerous lubrication points and adjustments that can be made.
It is very important to use the correct lubricants at the various lubrication points and not to skimp on this time-consuming step. The factory service manual actually specifies something like five or six different lubricants, depending on the lubrication point!
This Dual 601 needed the usual cleaning of the spindle bearing, fresh synthetic oil, various lubrication and some small adjustments before receiving a good cleaning and overhaul of the tone-arm and cartridge alignment.
Once this was all done, she worked absolutely beautifully. A few images describing some of these steps can be found below.