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Setton RS660 Power Switch Question

gregmcm

gregmcm

Active Member
I'm getting back to some work on my Setton RS660. The issue I'm dealing with is the power switch and speaker thump when I turn the unit on. Have done some reading and these switches are known to be problematic and were also used in some Lafayette units with similar problems.

I've managed a work around by connecting the speakers to the "B" speaker terminals and when I turn the unit on I wait for the speaker relay to engage and then move the selector switch to "B" and no issue with speaker thump when I do this.
If possible I'd like to have the switch work as intended so before I dig in I wanted to know:
- are the two capacitors attached to the switch (see photo which shows one of these and the other is located on the other side of the switch) a particular type of capacitor. I've never seen one like this before. They're marked .047uf 250V
- if these capacitors are out of spec could they be the cause of the speaker thump? I tested both and they read .061uf.
- would a .047uf 250V Film Capacitor be a suitable replacement.

I would note that there are no other issues with the switch - flickering etc.. I'm going to pull the switch and have a look inside as no doubt it could use at minimum a cleaning.

Thanksimage1 (3).jpeg
 
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Pulled the switch and upon inspection one side is totally cooked. The other side looks brand knew. I'm going to flip the good contacts to replace the cooked ones and wonder what purpose the good contacts were serving. Looking at them it appears they have never seen any wear. I'm assuming they are there for a purpose given there are connections that they bridge.


image1 (4).jpeg image2 (4).jpeg
 
Start at http://audiokarma.org/forums/index....orth-5-and-an-hour-or-so-of-your-time.504673/
The same switch is used in kenwood and pioneer receivers of the same era so searching will yield tons of information. Refurbishing contacts., using a relay with switch and other ideas.. Lafayette lr-9090 is the exact same (except cosmetics) as the 660.

FWIW when kenwood supplied switches under warranty for kr-4070, kr-5030 and kr-6030, the told repair people to parallel the two sets of contacts, increasing life expectancy considerably. My recommendation would be to use the switch to control an SCR as in the mentioned thread. YMMV
 
Thanks for the help. I dove in and proceeded as follows. Flipped the good contacts to replace the bad contacts. Took the bad contacts and replaced the two contact points with points I took out of a regular wall switch.

The points from the wall switch were connected to an arm that was thicker than the contact arms on the Alps switch. Because of this the wall switch points had enough material on the top side to allow me to do the following.

I was able to use a Dremel tool with a small grinding stone to grind the back of the wall switch points flush with the arm and using a utility knife was able to carefully remove the points. Did the same with the burnt points in the Alps switch. Took the good points and using a knife and small hammer made a split in the middle of the top/backside of the points. I then positioned the points in the Alps switch and using a small screwdriver and small hammer gently widened the split in the top of the points. I started with a small screwdriver and moved to a larger one. Once the points were secured I then used a small hammer to flatten the top so that the points were solidly secured.
Put the switch back in the Setton and now working as designed. All good.

*Photo not to scale but should give you a visual of the points and arm

image1 (5).jpeg
 
There is also a fix/mod using a 120v relay.
I did one years ago.
Basically the transformer is fed the AC from the relay and the relay is driven by the switch using a tap off the 120v line.

The arc snubbers must be removed from the switch or you’ll get a hum.
 
gregmcm said:
Pulled the switch and upon inspection one side is totally cooked. The other side looks brand knew. I'm going to flip the good contacts to replace the cooked ones and wonder what purpose the good contacts were serving. Looking at them it appears they have never seen any wear. I'm assuming they are there for a purpose given there are connections that they bridge.


View attachment 1108864 View attachment 1108866
Click to expand...

Note that is an X rated safety cap. I'd replace it with a *modern* X rated :)biggrin:) cap. An X2/275VAC will be fine and they are cheap. It's just really a spark killer so honestly any good film cap of similar value/voltage will work.
 
sregor said:
Start at http://audiokarma.org/forums/index....orth-5-and-an-hour-or-so-of-your-time.504673/
The same switch is used in kenwood and pioneer receivers of the same era so searching will yield tons of information. Refurbishing contacts., using a relay with switch and other ideas.. Lafayette lr-9090 is the exact same (except cosmetics) as the 660.

FWIW when kenwood supplied switches under warranty for kr-4070, kr-5030 and kr-6030, the told repair people to parallel the two sets of contacts, increasing life expectancy considerably. My recommendation would be to use the switch to control an SCR as in the mentioned thread. YMMV
Click to expand...

This is probably going to be the best long term solution for the Setton.
 
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