Faulty Dual CS 410 turntable - UK Vintage Radio Repair and Restoration Discussion Forum

WalterGibbons · 14th Jan 2020, 5:16 pm

I have an old Dual TT gathering dust as it won't power on - it worked perfectly till one day it just stopped. No warning, no deterioration, just dead.

It has its own power supply but it's potentially difficult to replace due to the length of the plug (or so I've been told). So I can't test it with an alternative power supply, and have absolutely no electronics skills or equipment to help me!

If you were in this situation, what would be the first thing(s) you'd bee checking? Assuming the power supply may be faulty, can someone point me in the direction of what I'd need to replace it? I've searched for info on the net and see nothing but frightening stories of fried TTs from using the wrong supply!

It's a Dual CS 410 (black model, not silver). I'll attach a pic of the power supply in case that helps.

Nickthedentist · 14th Jan 2020, 5:33 pm

12V at 20mA is a very small amount of power. Might this just be for an internal RIAA pre-amp?

Either way, have you used a voltmeter to check whether there's 12V or so at its output?

Output plug seems to be just a standard DC connector, albeit a long-reach one.

N.

Ted Kendall · 14th Jan 2020, 5:39 pm

Well. if you can get a meter across the power supply and see if it's giving any output, that would be a start. Admittedly, that is off-load, so perhaps 13-14v DC would indicate a healthy supply, in which case it is worth checking the cable. I'd have thought a generic supply of the right polarity wouldn't be too hard to source.

paulsherwin · 14th Jan 2020, 5:41 pm

I agree that 20mA seems low, but this deck is apparently very lightweight with a DC motor.

http://www.hifi-review.com/153673-dual-cs-410.html

snowman_al · 14th Jan 2020, 5:46 pm

Sorry for the really dumb question.
Has the belt fallen off?

WalterGibbons · 14th Jan 2020, 7:31 pm

Quote:

Originally Posted by snowman_al

Sorry for the really dumb question.
Has the belt fallen off?

If only life were that simple

WalterGibbons · 14th Jan 2020, 7:37 pm

Thanks for the replies.

When I said I have no electronics skills or equipment I genuinely mean NONE! I know how to play records, but that's as far as my turntable skills go. You could all be speaking Japanese to me right now for all I understand

I've searched before for a replacement power supply in case it's that simple, but I found this reply to someone else on another forum...

"what most probably happened now, is that, by applying the wrong polarity in combination with an enormously powerful power supply, you've probably fried the LA5512/µPC1470 regulator ic inside the motor. In other words: The electrician not only told you the wrong polarity of the turntable, but should have also warned you, that it's not wise to just connect a random type of 12 V DC power supply. Point is that with such a high excess current capability, an unregulated conventional power supply could even fry the motor electronics in the correct polarity, 'cause the load would be so insignificant that the power supply would apply a voltage that's higher than its nominal voltage and close to its idle voltage without load. However, given that the model you've used is a power supply for a pretty modern NiMH cell quick charger, it'll most probably rather be a compact primary switched switch-mode power supply anyway, so that it's a bit hard to predict, how that would behave in combination with a rather insignificant load."

which scared the Bejesus out of me!Is there anything specific I should be searching for to replace what I have?

paulsherwin · 14th Jan 2020, 7:52 pm

Your quoted post is talking about PSU polarity. The existing PSU should have a little drawing saying if the centre pin of the connector plug is positive (+ve) or negative (-ve). Any replacement must have the same polarity.

The current rating of any replacement isn't important, it's the voltage and polarity that matters.

Edward Huggins · 15th Jan 2020, 9:51 am

The OP's answer in his Post #7 goes a long way to explaining why some Posters never come back to us....
When an enquirer admits "No Skills", any reply which immediately starts off by suggesting voltmeter readings will bound to go way above their head.
Fortunately, Post #8 may go some way to bringing the OP back in to the fold.

Station X · 15th Jan 2020, 3:17 pm

Quote:

Originally Posted by WalterGibbons

If you were in this situation, what would be the first thing(s) you'd bee checking?

Quote:

Originally Posted by Nickthedentist

have you used a voltmeter to check whether there's 12V or so at its output?

When members seeking advice on an electrical or electronics problem say that they have no technical knowledge I wonder what sort of advice they expect to receive. The answer is unlikely to be something as simple as "turn screw 'A' three turns anti-clockwise". Sorry if that sounds frivolous, but that's the way it is.

The OP could replace the power supply and find that the turntable still doesn't work. A simple test with a voltmeter would show whether the existing power supply is faulty. There's plenty of online advice and YouTube videos showing how to use a voltmeter. If that's too difficult for the OP, then all he can do is replace the power supply, but he could well be wasting his money.

Nickthedentist · 15th Jan 2020, 4:17 pm

Walter (?) could have always asked: "What kind of meter should I get?" and "How should I use it to check for that 12 volts?", in which case, one of us would have given a nice simple reply which any person capable of posting on a forum like this would be able to follow.

Pleased to see he's made quite a few posts here, so he may well be back

WalterGibbons · 15th Jan 2020, 4:33 pm

I'm still here you know

A couple of months ago I asked on this very forum about a faulty Pioneer amp. I found the solution and fixed the amp thanks to advice received here. So, lack of skills or basic understanding need not be an obstacle.

If I owned a voltmeter I would happily use it. But I don't. And I probably wouldn't have much use for one in future, so I thought, based on the positive experience last time, I'd ask here again in case there's a simple fix or a solution that's obvious to an experienced person, but not to me. It's always worth a try.

If I replace the PSU and it doesn't work I can always return it. To me it seems like the first place to start. If it's not that I'll delve further.

WalterGibbons · 15th Jan 2020, 4:34 pm

What kind of meter should I get?
How should I use it to check for that 12 volts?

Nickthedentist · 15th Jan 2020, 4:40 pm

Ha ha, you're our new best friend now!

Seriously, if you have any interest in owning or fixing electronic stuff, buy yourself a meter. Screwfix, Halfords and so on do some, and you can get a really nice budget one for £15 or so if you shop around.

Here's some info from forum member Mark: http://www.markhennessy.co.uk/budget_multimeters/

I have one of the Aneng ones at work for day-to-day repairs on equipment. It's not as nice as my posh Fluke which cost about £250, but it's amazing for the price.

Trying to fix electronics without a meter is like trying to fix a bike with your eyes closed. It's not necessarily impossible, but...

Nick.

paulsherwin · 15th Jan 2020, 4:45 pm

You can buy very cheap meters that will do simple low voltage jobs like this:
https://www.ebay.co.uk/itm/Digital-M...r/272392173267

You simply touch the contacts on the PSU plug with the meter probes and it will display the voltage and polarity.

Station X · 15th Jan 2020, 4:46 pm

Just an example.

Did they still teach physics in schools in the 1980's or was it too hard a subject?

Nickthedentist · 15th Jan 2020, 4:51 pm

Yes, even the 99p (incl postage!!) ones will do for jobs like this.

WalterGibbons · 16th Jan 2020, 10:01 am

Quote:

Originally Posted by Station X

Just an example.

Did they still teach physics in schools in the 1980's or was it too hard a subject?

I'm not really sure how to take this response. I mean, was it intended to be extremely offensive?

Station X · 16th Jan 2020, 10:05 am

It was a serious question. I've heard of schools dropping subjects like foreign languages because pupils found them too difficult. Having helped out nephews and nieces with their home work I wasn't impressed with what they were being taught.

I also posted a picture showing how to measure the voltage. Took me a bit of time to set that up edit the picture and upload it for your benefit.

WalterGibbons · 16th Jan 2020, 10:11 am

Quote:

Originally Posted by Station X

It was a serious question. I've heard of schools dropping subjects like foreign languages because pupils found them too difficult. Having helped out nephews and nieces with their home work I wasn't impressed with what they were being taught.

I also posted a picture showing how to measure the voltage. Took me a bit of time to set that up edit the picture and upload it for your benefit.

Still don't understand your intent with the question, but thanks I guess.

14th Jan 2020, 5:16 pm	#1
WalterGibbons Tetrode Join Date: Oct 2008 Location: Glasgow, UK. Posts: 70	Faulty Dual CS 410 turntable I have an old Dual TT gathering dust as it won't power on - it worked perfectly till one day it just stopped. No warning, no deterioration, just dead. It has its own power supply but it's potentially difficult to replace due to the length of the plug (or so I've been told). So I can't test it with an alternative power supply, and have absolutely no electronics skills or equipment to help me! If you were in this situation, what would be the first thing(s) you'd bee checking? Assuming the power supply may be faulty, can someone point me in the direction of what I'd need to replace it? I've searched for info on the net and see nothing but frightening stories of fried TTs from using the wrong supply! It's a Dual CS 410 (black model, not silver). I'll attach a pic of the power supply in case that helps. Attached Thumbnails

14th Jan 2020, 5:33 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: Faulty Dual turntable 12V at 20mA is a very small amount of power. Might this just be for an internal RIAA pre-amp? Either way, have you used a voltmeter to check whether there's 12V or so at its output? Output plug seems to be just a standard DC connector, albeit a long-reach one. N.

14th Jan 2020, 5:39 pm	#3
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,675	Re: Faulty Dual turntable Well. if you can get a meter across the power supply and see if it's giving any output, that would be a start. Admittedly, that is off-load, so perhaps 13-14v DC would indicate a healthy supply, in which case it is worth checking the cable. I'd have thought a generic supply of the right polarity wouldn't be too hard to source.

14th Jan 2020, 5:41 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Faulty Dual turntable I agree that 20mA seems low, but this deck is apparently very lightweight with a DC motor. http://www.hifi-review.com/153673-dual-cs-410.html

14th Jan 2020, 5:46 pm	#5
snowman_al Octode Join Date: Dec 2018 Location: Llandeilo, West Wales, UK. Posts: 1,092	Re: Faulty Dual turntable Sorry for the really dumb question. Has the belt fallen off? __________________ Never Leave Well Enough Alone...

14th Jan 2020, 7:37 pm	#7
WalterGibbons Tetrode Join Date: Oct 2008 Location: Glasgow, UK. Posts: 70	Re: Faulty Dual turntable Thanks for the replies. When I said I have no electronics skills or equipment I genuinely mean NONE! I know how to play records, but that's as far as my turntable skills go. You could all be speaking Japanese to me right now for all I understand I've searched before for a replacement power supply in case it's that simple, but I found this reply to someone else on another forum... "what most probably happened now, is that, by applying the wrong polarity in combination with an enormously powerful power supply, you've probably fried the LA5512/µPC1470 regulator ic inside the motor. In other words: The electrician not only told you the wrong polarity of the turntable, but should have also warned you, that it's not wise to just connect a random type of 12 V DC power supply. Point is that with such a high excess current capability, an unregulated conventional power supply could even fry the motor electronics in the correct polarity, 'cause the load would be so insignificant that the power supply would apply a voltage that's higher than its nominal voltage and close to its idle voltage without load. However, given that the model you've used is a power supply for a pretty modern NiMH cell quick charger, it'll most probably rather be a compact primary switched switch-mode power supply anyway, so that it's a bit hard to predict, how that would behave in combination with a rather insignificant load." which scared the Bejesus out of me!Is there anything specific I should be searching for to replace what I have?

14th Jan 2020, 7:52 pm	#8
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Faulty Dual turntable Your quoted post is talking about PSU polarity. The existing PSU should have a little drawing saying if the centre pin of the connector plug is positive (+ve) or negative (-ve). Any replacement must have the same polarity. The current rating of any replacement isn't important, it's the voltage and polarity that matters.

15th Jan 2020, 9:51 am	#9
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,340	Re: Faulty Dual turntable The OP's answer in his Post #7 goes a long way to explaining why some Posters never come back to us.... When an enquirer admits "No Skills", any reply which immediately starts off by suggesting voltmeter readings will bound to go way above their head. Fortunately, Post #8 may go some way to bringing the OP back in to the fold. __________________ Edward.

15th Jan 2020, 4:17 pm	#11
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: Faulty Dual turntable Walter (?) could have always asked: "What kind of meter should I get?" and "How should I use it to check for that 12 volts?", in which case, one of us would have given a nice simple reply which any person capable of posting on a forum like this would be able to follow. Pleased to see he's made quite a few posts here, so he may well be back

15th Jan 2020, 4:33 pm	#12
WalterGibbons Tetrode Join Date: Oct 2008 Location: Glasgow, UK. Posts: 70	Re: Faulty Dual turntable I'm still here you know A couple of months ago I asked on this very forum about a faulty Pioneer amp. I found the solution and fixed the amp thanks to advice received here. So, lack of skills or basic understanding need not be an obstacle. If I owned a voltmeter I would happily use it. But I don't. And I probably wouldn't have much use for one in future, so I thought, based on the positive experience last time, I'd ask here again in case there's a simple fix or a solution that's obvious to an experienced person, but not to me. It's always worth a try. If I replace the PSU and it doesn't work I can always return it. To me it seems like the first place to start. If it's not that I'll delve further.

15th Jan 2020, 4:34 pm	#13
WalterGibbons Tetrode Join Date: Oct 2008 Location: Glasgow, UK. Posts: 70	Re: Faulty Dual turntable What kind of meter should I get? How should I use it to check for that 12 volts?

15th Jan 2020, 4:40 pm	#14
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: Faulty Dual turntable Ha ha, you're our new best friend now! Seriously, if you have any interest in owning or fixing electronic stuff, buy yourself a meter. Screwfix, Halfords and so on do some, and you can get a really nice budget one for £15 or so if you shop around. Here's some info from forum member Mark: http://www.markhennessy.co.uk/budget_multimeters/ I have one of the Aneng ones at work for day-to-day repairs on equipment. It's not as nice as my posh Fluke which cost about £250, but it's amazing for the price. Trying to fix electronics without a meter is like trying to fix a bike with your eyes closed. It's not necessarily impossible, but... Nick.

15th Jan 2020, 4:45 pm	#15
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Faulty Dual turntable You can buy very cheap meters that will do simple low voltage jobs like this: https://www.ebay.co.uk/itm/Digital-M...r/272392173267 You simply touch the contacts on the PSU plug with the meter probes and it will display the voltage and polarity.

15th Jan 2020, 4:46 pm	#16
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Faulty Dual turntable Just an example. Did they still teach physics in schools in the 1980's or was it too hard a subject? Attached Thumbnails __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

15th Jan 2020, 4:51 pm	#17
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: Faulty Dual turntable Yes, even the 99p (incl postage!!) ones will do for jobs like this.

16th Jan 2020, 10:05 am	#19
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Faulty Dual turntable It was a serious question. I've heard of schools dropping subjects like foreign languages because pupils found them too difficult. Having helped out nephews and nieces with their home work I wasn't impressed with what they were being taught. I also posted a picture showing how to measure the voltage. Took me a bit of time to set that up edit the picture and upload it for your benefit. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.