Dual 606 record player – Restoration (part 1)

If you read the very first article on this blog you might have seen that I’m rebuilding old record players. And lately I just started over with my third one; it’s a 1980 Dual 606. Back then it was a mid-range player, but much of the hardware was taken unchanged from the high-end equipment, most notably the drive-train (more on that later).

On a first sight the device was in a very good condition when I received it, but there were some issues with the electronics – rather common for devices this old – which had to be fixed. The first part of this series of articles is about technical details and how to break the turntable open.

Spec-sheet: Dual 606 record player

  • Semi-automatic operation
  • Electronic Direct Drive
  • Strobe light
  • Adjustable anti-skating
  • Adjustable anti-resonance filter

The Dual EDS 500 direct drive:

  • Speeds: 33 1/3 rpm and 45 rpm
  • Start up time: 2 – 2.5 sec. at 33 1/3 rpm
  • Wow and flutter: ±0.05% DIN / ±0.03% WRMS
  • Rumble: Unweighted: 50 dB / Weighted: 75 dB

Tonearm:

  • Length: 221 mm
  • Distortion free ULM (Ultra Low Mass – a Dual buzzword) tonearm
  • Mount: 4 point gimbal bearing
  • Counterbalancing: tuning anti-resonator
  • Tracking force range: 0 – 3 grams (dynamically applied)
  • Max cartridge weight: 6.4 grams (ULM mount!)

Platter:

  • Weight: 1.4 kg
  • Size: 304 mm
  • Removable & non-magnetic

 

Originally the Dual 606 was shipped with a Dual brand Ortofon cartridge – the TKS155. The needle is a DN155E which isn’t actually as bad as one might expect from it being “stock equipment”.

Crack it open!

Okay, let’s start!

Getting ready:

For the following you will need:

  • some screwdrivers (slot and phillips)
  • a set of pliers
  • a few boxes to store the screws and other small parts
  • two boxes (cardboard boxes do fine, books too) having the same height (approx.) as stands for the chassis

Step 1: Remove the stylus

Safety first! The stylus is one of the most expensive parts and some times hard to replace (not here luckily). First we flip over the stylus cover.

Now lock the tonearm. Then we have to unscrew the upper securing screw (be careful with the aluminum screw – it’s a very soft alloy ! You may damage it if you use a tiny screwdriver) …

…to be able to pull the needle:

Finally tighten the securing screw again to keep the cartridge safely in place.

Step 2: Remove the counterweight

There’s a screw right behind the tracking force control. Open it and pull the counterweight out.

Step 3: Remove the platter

This one is quite easy, just pull the platter straight up (don’t worry if there’s some drag – 30+ years of gravitational force and dirt apply…) and it should come apart. Put it aside, we won’t need it until one of the last parts of this series.

Step 4: Unscrew cables from the frame

Be sure to free the cables prior to lifting the chassis. I forgot to take care of that and had to put things back together again… Simple remove the two screws in the back of the frame:

Step 5: Lift the chassis

To do so we start by loosening the transportation lock screws; it’s the same story as for all old(er) Dual devices. You can find three of them on the top of the record player (marked in red below):

Positions of the transportation lock screws on a Dual 606

Positions of the transportation lock screws on a Dual 606

To lift the chassis you need to twist the lock screws (the part of them beneath the chassis has to move away from the frame):

Twist the transportation lock screws

Twist the transportation lock screws

When two of the three lock screws are free you can carefully lift the chassis upwards (take care of the cables in the back side).
Note: I always remove the front and the right lock screws first – it seems easier for me to do so.

And that’s what you should see:

Beneath the chassis of a Dual 606

Beneath the chassis

Now remove the whole chassis from the frame, and put it on the boxes – upside down! For me it worked out best to have one box on the front and one in the back of the chassis.

 Step 6: Disconnect everything

Now we can proceed by disconnecting all the cables we don’t need; namely the mains connector, the RCA plugs and the ground cable.

To remove the mains cable and the ground cable unfasten all screws marked in the first picture below. Then lift the two clamps of the mains cable with a tiny screwdriver (in the black mains switch box).

Next we will disconnect the RCA cable. For this remove the cover of the audio circuit breaker and then the audio cable clamps.

Finally unscrew the clip on the chassis. Done!

Further proceeding

Mainly part II will deal with the electronics of the Dual 606.

Most electrolytic capacitors had very bad ESR values which means they were close to blowing up. The record player was running, but I know that these parts just would have failed soon. The classic example of what’s to repair when you get an old “broken” Dual turntable is the AC filtering capacitor in the mains switch. Those babies love to go boom! What happens is that the plastic case starts to get hairline cracks with time and moisture gets in. This lowers resistance (remember caps should have infinite resistance ideally). Because of that the cap starts to heat up, which finally ends up pushing poles together and then… BOOM!  You get some magic smoke and a nasty smell all over your place!

I hope you enjoyed reading this. If you have any question, just leave a comment below.

You can find further information about the Dual 606 here:

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About Yannic

Yannic is a daytime freelance software developer, inventor and full-time geek. There's not much technical stuff he wouldn't like to crack open to see how they work. As a perfectionist most of the things he's getting into are completed in the most fashionable manner.