What modern component should I use for switch click suppresion? - UK Vintage Radio Repair and Restoration Discussion Forum

Nickthedentist · 22nd Aug 2014, 10:11 am

Hi everyone,

I'm (still) restoring my Dynatron Mazurka which has a Garrard 4HF deck.

The click suppressor across the motor switch's contacts is the original, and has just started oozing wax

So what should I replace it with? I usually use CPC so something from their range would be ideal. I presume Class X would be OK as there's no risk if it were to fail short circuit.

The choices from the "Capcitors, Suppression" section seem to be:

Ceramic disc rated at 250v AC, Class X1 (as well as Y1 or Y2) in a range of capacitance values from 0.1nF to 10nF,
Metallised propylene, 440v AC, Class X1, 10nF to 1uF,
Metallised propylene, 275V AC, Class X2, from 10nF to 3u3F,
Metallised paper, Class X2 with integral 47R or 100R series resistor, 250V AC, 47nF to 470nF (the infamous Rifas!)

Any suggestions please? I know it's a bit of an old chestnut, but I've done some forum searches and not come up with anything definitive.

Nick.

kalee20 · 22nd Aug 2014, 11:07 am

Stick with the original value. A resistor in series is a good idea - 22 ohms or so - otherwise you will get sparking when the contacts close.

Any of the first 3 will be OK.

Tractorfan · 22nd Aug 2014, 11:15 am

Hi,
There are devices which contain a capacitor and 120 ohm resistor combined and made for the purpose. I think they go under the brand name of 'Quench-arc', or something similar, if that's any help.
Cheers, Pete.

julie_m · 22nd Aug 2014, 2:36 pm

There is a purpose made part: Maplin RG22Y which combines a suitable resistor and capacitor together in a single package.

SteveCG · 22nd Aug 2014, 3:42 pm

You may come across the term 'snubber' for these click reducing capacitors which have a series resistor as well.

I've replaced failed Rifa snubbers with the appropriate value of X2 type capacitor with the appropriate value of resistor wired in series. I use 1 watt rated resistors for this role because of their higher maximum working voltage.

DOFFERY · 23rd Aug 2014, 12:45 pm

Why not use the normal suppressor items, these contain the two items mentioned & are either long lead or fixed type?

Coin.

Maarten · 23rd Aug 2014, 5:51 pm

Since they may still have impregnated paper dielectric as the infamous RIFAs do. Nothing is mentioned in the link to Maplins, so I fear the worst.

audiomik · 24th Aug 2014, 7:22 am

Nick
whilst I can't remember the eventual value of capacitor used for a turntable motor switch suppressor, I do remember trying one of the larger values shown in your list in the first post of this thread.

Unfortunately this had the effect of providing the motor with sufficient current through the capacitor to run with the switch open.

Suggest that you try 10nF 250VAC with a 100R in series to start with.

hope this assists
Mik

Nickthedentist · 29th Aug 2014, 5:07 pm

Thank you everyone for all the helpful suggestions.

The answer, it would seem, should have been RTFM, which states quite clearly that the original component is 0.05uF in series with 220R.

I will gut the original, and try to fit one of the 47nF metallised propylene ones + a 220R resistor inside.

BTW I couldn't find the RC suppressors/snubbers mentioned above simply because they're not in the Capacitors (supression) section of the CPC paper catalogue - they're in the Suppressors section (of course

) so thanks for reminding me of those.

Next daft question... What voltage rating for the resistor would be the bare minimum acceptable?

Nick.

22nd Aug 2014, 10:11 am	#1
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,844	What modern component should I use for switch click suppresion? Hi everyone, I'm (still) restoring my Dynatron Mazurka which has a Garrard 4HF deck. The click suppressor across the motor switch's contacts is the original, and has just started oozing wax So what should I replace it with? I usually use CPC so something from their range would be ideal. I presume Class X would be OK as there's no risk if it were to fail short circuit. The choices from the "Capcitors, Suppression" section seem to be: Ceramic disc rated at 250v AC, Class X1 (as well as Y1 or Y2) in a range of capacitance values from 0.1nF to 10nF, Metallised propylene, 440v AC, Class X1, 10nF to 1uF, Metallised propylene, 275V AC, Class X2, from 10nF to 3u3F, Metallised paper, Class X2 with integral 47R or 100R series resistor, 250V AC, 47nF to 470nF (the infamous Rifas!) Any suggestions please? I know it's a bit of an old chestnut, but I've done some forum searches and not come up with anything definitive. Nick.

22nd Aug 2014, 11:07 am	#2
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,081	Re: What modern component should I use for switch click suppresion? Stick with the original value. A resistor in series is a good idea - 22 ohms or so - otherwise you will get sparking when the contacts close. Any of the first 3 will be OK.

22nd Aug 2014, 11:15 am	#3
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Re: What modern component should I use for switch click suppresion? Hi, There are devices which contain a capacitor and 120 ohm resistor combined and made for the purpose. I think they go under the brand name of 'Quench-arc', or something similar, if that's any help. Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

22nd Aug 2014, 2:36 pm	#4
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: What modern component should I use for switch click suppresion? There is a purpose made part: Maplin RG22Y which combines a suitable resistor and capacitor together in a single package. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

22nd Aug 2014, 3:42 pm	#5
SteveCG Nonode Join Date: Jun 2009 Location: Herefordshire, UK. Posts: 2,495	Re: What modern component should I use for switch click suppresion? You may come across the term 'snubber' for these click reducing capacitors which have a series resistor as well. I've replaced failed Rifa snubbers with the appropriate value of X2 type capacitor with the appropriate value of resistor wired in series. I use 1 watt rated resistors for this role because of their higher maximum working voltage.

23rd Aug 2014, 12:45 pm	#6
DOFFERY Retired Dormant Member Join Date: Aug 2004 Location: Blackpool, Lancashire, UK. Posts: 1,488	Re: What modern component should I use for switch click suppresion? Why not use the normal suppressor items, these contain the two items mentioned & are either long lead or fixed type? Coin.

23rd Aug 2014, 5:51 pm	#7
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,199	Re: What modern component should I use for switch click suppresion? Since they may still have impregnated paper dielectric as the infamous RIFAs do. Nothing is mentioned in the link to Maplins, so I fear the worst.

24th Aug 2014, 7:22 am	#8
audiomik Retired Dormant Member Join Date: Oct 2010 Location: Bath, Somerset, UK. Posts: 96	Re: What modern component should I use for switch click suppresion? Nick whilst I can't remember the eventual value of capacitor used for a turntable motor switch suppressor, I do remember trying one of the larger values shown in your list in the first post of this thread. Unfortunately this had the effect of providing the motor with sufficient current through the capacitor to run with the switch open. Suggest that you try 10nF 250VAC with a 100R in series to start with. hope this assists Mik

29th Aug 2014, 5:07 pm	#9
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,844	Re: What modern component should I use for switch click suppresion? Thank you everyone for all the helpful suggestions. The answer, it would seem, should have been RTFM, which states quite clearly that the original component is 0.05uF in series with 220R. I will gut the original, and try to fit one of the 47nF metallised propylene ones + a 220R resistor inside. BTW I couldn't find the RC suppressors/snubbers mentioned above simply because they're not in the Capacitors (supression) section of the CPC paper catalogue - they're in the Suppressors section (of course ) so thanks for reminding me of those. Next daft question... What voltage rating for the resistor would be the bare minimum acceptable? Nick.