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Seeking help for push-button switches to rotary selector

OhMagoo

New Member
Thread starter #1
Hi all!

New guy here, seeking help to convert 4 push-button switches into one rotary selector switch. This is on an old Craig H340, which has (imo) a very ugly set of 4 selector switches for the different inputs.

Craig_H340_Switch.jpg

When a switch is off, it's two poles to the left will be connected to it's two poles in the middle(output). When the switch is pressed into the on position, of course the two middle poles connect to it's poles on the right (input). All output appears to go out through the middle poles on the tape switch.

Im having a hard time to wrap my head around how to convert this to a single 4 position rotary selector switch. Any help would be much appreciated!
 
#2
Ok what you need is a 2 pole 4 way rotary with the wires connecting to the existing tape switch poles connected to the rotary poles. The first position of the rotary is tape, 2nd phono, 3rd fmx & 4th am.
As you have not supplied more information I cannot quite tell you what the weirdness is around the FMX & AM connections!
 

cowboybob

Well-Known Member
Most Helpful Member
#3
... Im having a hard time to wrap my head around how to convert this to a single 4 position rotary selector switch. ...
No kidding :banghead: !

You're going to have to emulate (with the rotary switch) 4 DPDT switches that will return to an "OFF" position, any time an alternate rotary switch position is elected, in order to maintain the "Pass-Through" connectivity the schematic indicates.

To me, this would require a very complex rotary switch system with four decks, and/or a very complicated, custom pin arrangement on just one deck (both required for maintaining existing "pass-through" connectivity). In other words, a custom rotary switch. Good luck with that.

And fitting the rotary switch into the push-buttons' connection positions on the PCB would be a very difficult task.

I not being facetious suggesting that you "leave well enough alone" on the project and learn to love the ugliness of the current system.
 
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Thread starter #4
As you have not supplied more information I cannot quite tell you what the weirdness is around the FMX & AM connections!
You nailed it - that was throwing me off and I couldnt figure it out, even with the schematic. (Its available here if you still have a curiosity)


To me, this would require a very complex rotary switch system with four decks, and/or a very complicated, custom pin arrangement on just one deck (both required for maintaining existing "pass-through" connectivity). In other words, a custom rotary switch. Good luck with that.
I was afraid this would be the case. I was hoping that someone with a sharper eyes and mind than I have would see a way around the pass-through stuff to a much simpler solution.

I not being facetious suggesting that you "leave well enough alone" on the project and learn to love the ugliness of the current system.
Taken as friendly advice :)
Ive been looking at its ugly for nearly 40 years, I guess a few more wont hurt lol

Thank you both for your replies!
 

rjenkinsgb

Active Member
#5
The "pass through" wiring on the buttons only prevents more than one input being active at the same time.

With a rotary switch that is impossible anyway - so all you need is a two-pole four way switch.

It's exactly as Fourtytwo said.
Common terminals are output - the centre pins of the tape switch - and the four ways are the inputs from the right hand terminals of the four switches.

That's it, in total.
 

cowboybob

Well-Known Member
Most Helpful Member
#6
The "pass through" wiring on the buttons only prevents more than one input being active at the same time.

With a rotary switch that is impossible anyway - so all you need is a two-pole four way switch. ...
All true, except for the FMX arrangement that, when selected, sends the Gnd in one doirection and when de-selected in another direction that must be maintained for all other selections. So, anyway, a third pole if not a third deck.

But my real issue was with mounting the rotary
 
Thread starter #8
The "pass through" wiring on the buttons only prevents more than one input being active at the same time.

It's exactly as Fourtytwo said.
Common terminals are output - the centre pins of the tape switch - and the four ways are the inputs from the right hand terminals of the four switches.

That's it, in total.
After having a couple looks at it, i get it now. I am going to try a 3 pole and see how she goes...
[
All true, except for the FMX arrangement that, when selected, sends the Gnd in one doirection ...
But my real issue was with mounting the rotary
The FM and AM were throwing me off. The mounting is no problem, i should have mentioned earlier that i am re-boxing the electronics in a new housing , so will panel mount the pots and switches.

Thanks all for your replies!!
 

OhMagoo

New Member
Thread starter #9
The "pass through" wiring on the buttons only prevents more than one input being active at the same time...
.Common terminals are output - the centre pins of the tape switch - and the four ways are the inputs from the right hand terminals of the four switches.
.
All true, except for the FMX arrangement that, when selected, sends the Gnd in one doirection and when de-selected in another direction that must be maintained for all other selections. So, anyway, a third pole if not a third deck.
.
Ok what you need is a 2 pole 4 way rotary with the wires connecting to the existing tape switch poles connected to the rotary poles. The first position of the rotary is tape, 2nd phono, 3rd fmx & 4th am.
As you have not supplied more information I cannot quite tell you what the weirdness is around the FMX & AM connections!
After getting a chance to work on this a bit, the 3P4T did work perfectly for this, so thank you all very much gentlemen!

The 3rd pole was used as the ground and only passed it the one direction with the rotary switch to the FM selection, otherwise passed it the other direction when any other position was selected, as I jumpered them together.

The other part of the FM selector that was puzzling me did make sense after the FM pushbutton's ground was taken care of - one channel of the FM stereo input was at the top right pin of the pushbutton (as looking at it in the pic), but the other channel was routed through the top left pin of the AM pushbutton

Now comes the fun part of re-boxing it so it looks presentable!
.
craig_h340_remains-of-innards01.jpg
 
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