Problem with rotary Grayhill switch

Hello,

I just finished my second Pultec EQ and now I came upon this little problem. Let me explain: for the 3k to 16k frequency rotary switches I used two Grayhill switches (rotary type 1P-12pos 2 deck) with digikey part number GH7103-ND (http://www.digikey.be/product-search/en?x=0&y=0&lang=en&site=be&KeyWords=GH7103-ND).
Now I finally finished my Pultecs and just used the switches, only to find there is a problem with one of the switches. There is no connection between the two decks and therefor the switch is not working at all. It seems now that it is bypassed. First I thought it was a bad connection, because when I turned the switch there was a lot of noise and the, let's say boosted 3k would fall away and come back as I tapped on the switch. Then I turned the switch for 1 minute and it got better, but today the switch is not working anymore at all. There is no noise when I turn the switch and when I boost 3k, or 5k, or whatever, there is nothing happening.
When measuring the good switch on my other Pultec, there is, of course, a connection between the two decks, but on the bad switch there is no connection at all.

Anyone any thoughts on this one?

Thanks a lot!

There is not supposed to be any connection between the two decks of this switch as supplied. There will only be connection between them if you make it. Can you attach a schematic of what you are building showing how these switches are supposed to be wired?

Cheers

Ian

I have been troubleshooting an EQN for one of our members here and indeed one Grayhill is completely kaput. There is no connection between the wiper and the contacts on bothe gangs. One gang on the other switch also has no connection. All brand new switches. 

sahib said:

I have been troubleshooting an EQN for one of our members here and indeed one Grayhill is completely kaput. There is no connection between the wiper and the contacts on bothe gangs. One gang on the other switch also has no connection. All brand new switches.

Click to expand...

Wow! That is very poor for a company with a reputation like Grayhill. I trust you have informed them. Maybe there's a whole batch like that.

Cheers

Ian

That's no good news indeed. I already contacted technical support at Digikey where I bought the switches. Hope to hear them soon.

Ian, schematic is attached here. It's the 7 position switch with connection to the inductor.

Thanks,
Bram

Well, you live and learn Ian, as you know. It would never-ever occur to me. I was expecting a short capacitor to ground and it turned out to be an open Grayhill.

There is now another thing that I can't take for granted. I have just received 250 off Grayhill for a product and I am going to check them one by one before they are assembled.

Also wanted to ask: is it normal that you hear clicks in the speakers when turning the Grayhill switches?

Thanks

In your case it should not.

sahib said:

I have been troubleshooting an EQN for one of our members here and indeed one Grayhill is completely kaput. There is no connection between the wiper and the contacts on bothe gangs. One gang on the other switch also has no connection. All brand new switches.

Click to expand...

I received a bad switch as well.  2P6T, one of the poles had no connection.  Took it apart, and one of the shorting pieces was missing.  Gonna have to check them all now as well, since they are a real PITA to unsolder.
Best,
Bruno2000