Stone dead Dual 505/2

snap, crackle and pop
edradour
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Stone dead Dual 505/2

Post by edradour » 14 Jan 2020 00:22

No life at all - switch linkage appears to be working. Any ideas?

Alec124c41
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Re: Stone dead Dual 505/2

Post by Alec124c41 » 14 Jan 2020 00:54

If you don't have one, get a digital multi-meter.
Use it to check continuity in the power cord, first. Then check the switch. Go from there.
Manuals: https://www.vinylengine.com/library/dual/cs-505.shtml

Cheers,
Alec

edradour
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Re: Stone dead Dual 505/2

Post by edradour » 14 Jan 2020 11:22

Thanks Alec - old school here - strictly analogue MM (I like to watch that needle swing). If there no contacts hidden behind that PCB doing something I don't know about - I have a dead switch. Are parts available for these old things?

All best - Roger

Tinkaroo
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Re: Stone dead Dual 505/2

Post by Tinkaroo » 14 Jan 2020 12:50

I would clean the switch contacts with contact cleaner first before declaring it dead.

Alec124c41
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Re: Stone dead Dual 505/2

Post by Alec124c41 » 14 Jan 2020 15:02

I have taken switches apart to clean them. Sometimes it works. ;)
Sometimes the switch mooves a bit, and has to be repositioned.
Good luck.

Cheers,
Alec

edradour
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Re: Stone dead Dual 505/2

Post by edradour » 14 Jan 2020 23:47

Cheers - I shorted out the switch and it all came to life (auto mechanisms somewhat confused!!). My eyesight is not what it was and I thought the switch was the probe type, like on old Garrards, but it's just a common push-to-make button switch, so, hopefully not too difficult to replace. First one of these I have worked on - all a bit tacky inside, but I am deeply impressed by the accessibility for service/repair.

spensar
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Re: Stone dead Dual 505/2

Post by spensar » 15 Jan 2020 04:27

The micro switch on these models are common problem with these models and a clean out with contact cleaner normally does it without needing to take the switch apart, but mileage will vary of course. I have had a couple that would not fire up and that is all it took.

edradour
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Re: Stone dead Dual 505/2

Post by edradour » 15 Jan 2020 11:29

I did try a squirt of Servisol but it did no good - that is one of the cheapest and nastiest micro switches I have seen - same goes for the rest of it really. But it's nice and quiet and stable, so handsome is as handsome does I suppose.

Tinkaroo
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Re: Stone dead Dual 505/2

Post by Tinkaroo » 15 Jan 2020 13:47

edradour wrote:
15 Jan 2020 11:29
I did try a squirt of Servisol but it did no good - that is one of the cheapest and nastiest micro switches I have seen - same goes for the rest of it really. But it's nice and quiet and stable, so handsome is as handsome does I suppose.
I took a look at the switch on the 505 and it looks to be a part of the circuit board.

Therefore to change the switch you may have to change the board and you probably want to change some of the safety caps on it at the same time. I see that Dualfred has the board but recommends changing the caps on it.

The safety caps are sometimes referred to as knallfrosch or exploding frogs since when they go they do so with a bang and some not so nice smoke.

Before changing out the switch it might be better to try cleaning it again and working it in and out a bunch of times. The alternative is as mentioned unless you can fit a microswitch in and have it maintain the same position for switching.

edradour
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Re: Stone dead Dual 505/2

Post by edradour » 15 Jan 2020 17:09

Yes it's pcb mounted but hopefully not too difficult to replace. The problem so far is finding a replacement momentary switch. I might have to do some careful measuring and hope to get something close enough to work. Thanks for the warning about the exploding frogs (!) parallels with 'pond life' are probably a bit unfair. :)

Tinkaroo
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Re: Stone dead Dual 505/2

Post by Tinkaroo » 15 Jan 2020 17:18

Dualfred has this micro switch and in a separate listing the whole board with switch.
For what it's worth.

https://www.dualfred.de/Standard-Parts/ ... 40-en.html

edradour
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Re: Stone dead Dual 505/2

Post by edradour » 15 Jan 2020 17:44

Many thanks - that's really helpful. I don't think it's an exact match but I'll get in touch and see if they have the correct one. It would save an awful lot of fiddling.

Tinkaroo
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Re: Stone dead Dual 505/2

Post by Tinkaroo » 15 Jan 2020 17:51

As mentioned they also have this board with switch.

https://www.dualfred.de/Drive/Electroni ... 65-en.html

edradour
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Re: Stone dead Dual 505/2

Post by edradour » 15 Jan 2020 20:04

Tinkaroo wrote:
15 Jan 2020 17:51
As mentioned they also have this board with switch.
And that would save me even more fiddling, as well as postponing the inevitable frog explosion!! Thanks for making the effort to post those links :)

Roger

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Re: Stone dead Dual 505/2

Post by Bic 410 » 15 Jan 2020 21:05

Take care because there is a note about the caps on the complete board: they are cracked and should be replaced. So I think it's best to fix your actual switch.

I have fixed many of these switches. There are two kinds of switch on these boards.

The black one, with the solder pins on the same side, are the easiest to repair. Once the switch is unsoldered, it can be opened very easily and you will have an easy access to the contacts. You can polish the contacts with ultra fine (2000 grit) sandpaper, or cardboard saturated with contact cleaner.

The red one, with one solder pin on one side and the second solder pin on the "back side" of the switch is more difficult to repair. You will need to unsolder the switch and grind the rivets (on the hollow side of the rivet, not on the head side of the rivet) in order to open the switch. Then you will need to remove the small metal pieces with the contact area, for polishing the contacts. There is a spring and it is touchy to rearrange the switch. Take pictures before dismantling this switch...

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