Dual 601 Belt-Drive Turntable Repair

Dual 601 Belt-Drive Turntable Repair

The classic Dual 601 turntable is not as well-known as contemporaries by Thorens and Rega, but they are a great turntable.

This 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.

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 not return. I’ve described a similar repair on another Dual 601 here.

This problem is resolvable, 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 lubricant at each lubrication point and not to skimp on this time-consuming step. The factory service manual actually specifies five or six different lubricants and I have modern equivalents for these here in the workshop.

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 follow.

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So here she is, sub-platter removed, showing the layout of the deck. You can see the central spindle bearing, speed change mechanism near the speed change lever and the tone-arm arrangement.
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The first job is to remove the turntable mechanism from the chassis.
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Some detail on the tone-arm stylus pressure adjustment. Note that this design utilizes a spring to provide the down-force, as opposed to a counterweight in other decks. Here the counterweight is set to achieve a zero-balance, with the spring doing the rest.
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Speed change mechanism detail…
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Here we see the underside of the deck, with main orange cam which controls the deck function. The motor is situated at the bottom-right, arm return mechanism is at the top-left.
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The control cam in more detail. this needs to be cleaned and carefully greased.
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And this is the dreaded arm-return mechanism. this causes problems on basically all of these decks, but it is easily remedied.
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After reassembly, we are playing a test record and checking for auto-return functionality.
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And here she is, all serviced, repaired and good to go!

Liquid Mike

At 10 I was pulling apart electronics and by 13 I'd have Dad's hi-fi in pieces when my parents went out! Later, I started Liquid Audio, a specialist electronics repairer known for detail-focused service, repair and restoration of hi-fi electronics & turntables. Keeping classic hi-fi gear alive and well is what we do. Our mission: to deliver TLC for classic Japanese, American and European hi-fi stereo equipment. In my spare time, I ride motorcycles, travel, listen to music and research interesting topics.

This Post Has 11 Comments

  1. Bob

    Thank you Mike, appreciate your feedback!

  2. Bob

    Thanks Mike. Can you identify specific area’s that need to be lubed? Also do you suggest a lite grease?

    1. Liquid Mike

      Hi Bob and no problem! I suggest referencing the service manual for this and other technical information. From memory it’s well written and contains the necessary diagrams, recommended lubricants, tools, adjustments and so on. This saves me a ton of time re-writing, summarising etc!

  3. Bob

    John, I recently acquired a brand new 601 in a sealed box for 40 years or so. Everything works but the auto start and auto return. I assume the lube dried out after decades of sitting in a box. Follow your guidelines noted above?
    Thanks,
    Bob

    1. Liquid Mike

      Hi Bob, it’s Mike and very nice acquisition there. The deck will need a complete service to resolve the lubricant issues and shouldn’t be used until that happens. The article is a great starting point but it’s not a tutorial and there’s a ton of detail I couldn’t include. You’ll need various lubricants, solvents etc and in most cases this would be a job for a specialist familiar with these machines but if you feel like having a go, be careful and best of luck!

  4. Duncan Cochran

    Hi
    Can the performance be improved with a replacement mat? Is there any VTA adjustment? Thanks

    1. Liquid Mike

      Hi Duncan, there’s no VTA adjustment via tonearm settings, but some adjustment can be made via the mat, careful choice of cartridge and headshell spacers. Setup and mechanical state of service are critical with these machines. They are good decks but more maintenance intensive than many others and the Dual headshell/cartridge mounting system is prone to causing trouble, so be very careful with that part of the machine.

  5. Ben

    Hi there, just received a 601 but don’t know where the pitch control switch is.

    1. Liquid Mike

      Hi, the first thing I suggest you do is search for a manual, that way you’ll be able to get your head around the sometimes slightly unusual Dual control layout on these older decks. Speed switching on Duals is on the left. Also, have your deck thoroughly serviced if it hasn’t been done in a few years, these mechanical decks absolutely thrive on regular maintenance and were designed to receive it.

  6. Jon Stannah

    Hi, How do you remove the base. Undone the screws but seems to be stabled and glued?

    1. Hi John, the 601, like many other Duals, uses three screws which hold the deck to the chassis. These must be loosened and moved out the slot they sit in to release the deck. Be very careful, it’s very easy to make one of these much worse if you don’t know what you are doing. These Dual decks are mechanically complex, you need several types and grades of lubricants and there are many points to lubricate and/or adjust.

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