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Rotary Switch Question

L

LinuxGuru

Well-Known Member
Hi!

It would be nice if someone could help me - I have some difficulty interpreting schematic diagram with 4-pole 5-pos rotary switch (when I am was in university, we used slightly different Russian GOST standard notations).

Original switch fall apiece and now I am need to replace it with another one.

Its 2 deck, 4 pole, 5 pos rotary switch used to select input on integrated amplifier. It switches not only input connectors (marked with red "1"), but additionally RC circuit in twin triode preamplifier (marked with red "2").

Now the question about corresponding positions:
switch 1/2 - 1/7, 2/8, 3/9, 4/11, 5/12
or 1/9, 2/10, 3/11, 4/7, 5/8 ???

In other words:
when switch 1 stands in position #1, what is the corresponding position of switch #2 - #7 or #9?
when switch 1 stands in position #2, what is the corresponding position of switch #2 - #8 or #10?

Schematic diagram (one channel) enclosed.

Thanks in advance.
 
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I think they're drawn in the same positions.

So, to me, it looks like:

Switch #1, section 1. pin 1 (mic input) is connected to common pin6
Switch #1, section 2. pin 9 (NFB for mic eq) is connected to common pin 8

Usually, these multi ganged switches are drawn schematically to represent one switch shaft position. So, in the schematic, mic is selected with it's required gain and eq negative feedback components.

The switche's moving contact is not the same for each section. That is too bad, because it will make replacing it difficult.
 
Jon is right.

The important point here is that pin6 is the "output" pin for switch 1, section 1.

Also, pin 8 is the "output" pin for section 2 of switch 1.

In schematic, multi ganged switches are drawn in the same position (say, full clockwise for example).

For replacement, if the switch is wired, as opposed to a switch soldered directly on the printed circuit board, you can duplicate the section 2 switch with a switch similar to section 1 (easier to find) if you add a jumper between terminals 6 and 7 (on section 2)
 
I'm still a bit confused. Look at attached schematic and my notes in red.

There are 5 positions on rotary switch (mic, tape head, phono, tuner, AUX).
And only 4 feedback circuits. This is quite logical, since AUX/tuner are essentially the same.

And now:
Switch #1, pins (positions) #1 - 6, switch #2 pins # 7 - 12

Phono -> switch #1 position #3, switch #2 position #1
we have RC circuit in feedback R9 (3.3M) and in parallel C6/C7/R13/R14

Tuner -> switch #1 position #4, switch #2 position #12
RC circuit in feedback consist only of R9 (3.3M), since switch #2 position #12 is not connected anywhere.

AUX -> switch #1 position #5, switch #2 position #7
RC circuit in feedback consist of R9 (3.3 M) and R10 (22k) connected in parallel.

Signal level from Tuner and AUX inputs are the same - 150 mV, yet the level of negative feedback is absolutely different. I cannot explain all that, sorry.
 
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LinuxGuru said:
I'm still a bit confused. Look at attached schematic and my notes in red.

There are 5 positions on rotary switch (mic, tape head, phono, tuner, AUX).
And only 4 feedback circuits. This is quite logical, since AUX/tuner are essentially the same.

And now:
Switch #1, pins (positions) #1 - 6, switch #2 pins # 7 - 12

Phono -> switch #1 position #3, switch #2 position #1
we have RC circuit in feedback R9 (3.3M) and in parallel C6/C7/R13/R14

Tuner -> switch #1 position #4, switch #2 position #12
RC circuit in feedback consist only of R9 (3.3M), since switch #2 position #12 is not connected anywhere.

AUX -> switch #1 position #5, switch #2 position #7
RC circuit in feedback consist of R9 (3.3 M) and R10 (22k) connected in parallel.

Signal level from Tuner and AUX inputs are the same - 150 mV, yet the level of negative feedback is absolutely different. I cannot explain all that, sorry.
Click to expand...

Selector S1:
Position 1: "Mic", section 1. terminal 1 connect through switch to terminal 6
section 2. terminal 9 connect through switch to terminal 8
Position 2: "Tape Head", section 1. terminal 2 connect through switch to
terminal 6
section 2. terminal 10 connect through switch to terminal 8
Position 3: "Mag Phono", section 1. terminal 3 connect through switch to
terminal 6.
section 2. terminal 11 connect through switch to terminal 8.
Position 4: "Tuner", section 1, terminal 4 connect through switch to
terminal 6.
section 2, terminal 7 connect through switch to terminal 8.
Position 5: "Aux", section 1, terminal 5 connect through switch to
terminal 6
section 2, terminal 7 connect through switch to terminal 8.

Are your "notes" in red the "1", the "2" and arrows the extent of your notes??
I think you might be over complicating this switch. "Aux" and "Tuner" switch in the same negative feedback component. The other sttings require their own eq and gain settings.
 
Jon_Logan said:
Position 4: "Tuner", section 1, terminal 4 connect through switch to
terminal 6.
section 2, terminal 7 connect through switch to terminal 8.
Position 5: "Aux", section 1, terminal 5 connect through switch to
terminal 6
section 2, terminal 7 connect through switch to terminal 8.
Damn! I've got it. Section 2 has rotating disc with 2 connecting contacts, not one. Why Pioneer have not adopted Russian GOST standard for electronic notation ? :dunno:

Are your "notes" in red the "1", the "2" and arrows the extent of your notes??
.
Click to expand...

Nope, I wrote "notes aux, mic, t.head, phono" near feedback circuit elements.

PS. Thanks a lot, Jon_Logan ! Your assistance will make this amp sing again!
Click to expand...
Click to expand...
 
LinuxGuru said:
Damn! I've got it. Section 2 has rotating disc with 2 connecting contacts, not one. Why Pioneer have not adopted Russian GOST standard for electronic notation ? :dunno:
Click to expand...


....that's right. That contact on section 2 is wider, making terminal 7 contact the common terminal 8 for two positions. "Aux" and "Tuner". I saw the notes on your later post.
 
Linux, Now that you've got it... Do you see why Jon said in post #4 that this switch may be hard to find. The S2 mode switch will be still harder to find.

Switches with only one contact at a time (like section 1) are easy to find. If you add a jumper outside the switch, like I suggested, you can fix this pre-amp with easy to find switches.
 
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