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Old 26th May 2012, 12:14 pm   #1
howard
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Default Dual CS505-2 and CS505-4 turntable repairs

Hello again,

I was recently given two Dual CS505 turntables to repair, neither of them worked and they hadn't been used for many years. The first, a 1986 CS505-2 was missing its belt (a new one was supplied), the motor didn't start up when the arm was moved over to the start of a record and the pitch control didn't work. The second a 1991 CS505-4 Audiophile Concept model likewise didn't start up, it did have its belt but the speed change didn't work.

These are straightforward turntables to work on and come apart easily. Ensure that the turntables are disconnected from the mains when working on them. Owners and Service manuals for the Dual CS505 models are available from The Vinyl Engine website.

CS505-2
Lift off the perspex lid, secure the tonearm onto its pedestal with its clip, and fit the cartridge guard if available to protect the stylus. To remove the platter, remove the rubber mat and in the middle of the platter around the spindle is a round plastic locking washer, remove that by pressing down on it and turning it anti-clockwise while holding the platter - the one on this turntable was a devil of a job to shift - and then the platter can be lifted off the flywheel.

To access the underside of the deck, loosen off the two black cross-headed transit screws and then lift slightly and pull them both from the top end outwards which disengages locating washers at the bottom ends through slots in the sides of the pedestals underneath and the deck can then be lifted upwards a short distance and turned over and rested on the plinth.

When the arm is moved towards the start of a record, a microswitch is activated which powers up the motor, well this one was obviously tarnished inside so it was given a quick squirt of DeoxiT and the switch operated manually a few times. The deck was put back onto its plinth, the turntable plugged in and switched on and now the motor starts when the arm is moved to the start of a record and when moved to the end of the record the motor switches off.

The belt is straightforward to fit. Some replacement belts come with an alcohol pad for cleaning the flywheel and motor pulley but this one didn't and as they weren't particularly dirty I just wiped them clean with a damp cloth and then slipped the belt around the flywheel, fed it along the white guide and then around the motor pulley. The motor was switched on and the belt quickly settled down into its normal working position. The speed change was checked and that works OK.

The pitch control wasn't working because the pitch control belt was rotten and had broken in two places so was beyond repair. These are available on Ebay but at £21 or more apiece are rather expensive. Anyway I obtained an original toothed belt from a German dealer and that just slipped over the toothed cog on the bottom end of the pitch control knob and the toothed cog next to the motor pulley.

Some of the grease around the mechanism was showing signs of drying up so that was softened with some switch cleaner and then supplemented with some Electrolube plastic grease. In the service manual there are five lubrication points.

The turntable was then cleaned, the transit screws and platter replaced (line up the slot in the platter with the hole in the flywheel and rock the platter to ensure it has dropped into place) and secured with the locking washer by pushing down on it turning it clockwise, the rubber mat replaced, the tracking weight and anti-skating adjusted, the stylus cleaned with stylus cleaner, the lid replaced, the turntable connected to an amp and switched on and a record played. The Dual CS505-2 is now working fine.

CS505-4
This model is much the same as the CS505-2, the platter and trim differ. Lift off the perspex lid and hinges and secure the tonearm and cartridge as above. The platter comes off the same way as the CS505-2 as does the deck. The microswitch was cleaned with DeoxiT and a little Electrolube plastic grease was smeared around its little button as it was sticking a bit. The motor then started up OK when the arm was moved to the start of a record and switched off when the arm was moved over to the end of the record.

In the bottom of the plinth I found a small leaf spring which had fallen out from between the speed change lever and another lever which operates the speed change mechanism so that was put back into place and that then worked OK. In the service manual there are five lubrication points.

The turntable was then cleaned, the transit screws and platter replaced (place it onto the flywheel and turn the platter until it drops into place) and secured with the locking washer by pushing down on it and turning it clockwise, the rubber mat replaced, the tracking weight and anti-skating adjusted, the stylus cleaned with stylus cleaner, the lid replaced, the turntable connected to an amp and switched on and a record played. The Dual CS505-4 is now working fine.


The German built Dual CS505 turntables gained a good reputation for producing good sound quality and for reliability during the 1980s (I had one) and are probably the cheapest decent secondhand hi-fi turntable around at the moment. Build quality isn't bad, the plinths are plastic and a bit lightweight and consequently they do need to be situated well away from the loudspeakers to avoid acoustic feedback. Both these decks have the original Ortofon/Dual ULM 68E cartridge which tracks well at a tracking weight of 1.5 grams in the Dual Ultra Low Mass tonearm and which together produce decent sound quality and stereo from vinyl.

These turntables have lasted well, I am impressed.
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Last edited by howard; 26th May 2012 at 12:20 pm.
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Old 26th May 2012, 12:16 pm   #2
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Default Re: Dual CS505-2 and CS505-4 turntable repairs

And CS505-4 pics ...

Howard
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Old 29th May 2012, 1:20 pm   #3
ben
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Default Re: Dual CS505-2 and CS505-4 turntable repairs

Great work! I've done up quite a few Duals, very common in Spain. They just go on and on.
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Old 29th May 2012, 10:00 pm   #4
ianj
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Default Re: Dual CS505-2 and CS505-4 turntable repairs

Lovely budget hifi decks,sound good with the Ortophon om cartridges as well, I had a 505-2,gave it away in 1997 when I got a Technics sl deck,which I still use,and the Dual is still working today.
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Old 30th May 2012, 3:47 pm   #5
howard
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Default Re: Dual CS505-2 and CS505-4 turntable repairs

Quote:
Originally Posted by ianj View Post
Lovely budget hifi decks,sound good with the Ortophon om cartridges as well, I had a 505-2,gave it away in 1997 when I got a Technics sl deck,which I still use,and the Dual is still working today.
I was amazed how well these Dual turntables work and sound, they're not quite a Linn Sondek but considerably better value for money. Anyway I got to keep the CS505-2 for fixing the other one

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