Rob wrote:
On 2012-09-21 01:46, Robert Baer wrote:
Rob wrote:
On 2012-09-20 01:57, Jim Mueller wrote:
How did you determine the pin connections with an ohmmeter if the
switch
doesn't work? If the ohmmeter test shows that the switch does work,
then
the problem lies elsewhere.

The expected result (from looking at many multiple pole switches) was 4
groups of Form C (SPDT), with the center pin of each group of three
being common and upon actuation, all connections move the same direction
as in a slide switch. I think something mechanical slipped or broke and
is reversing the action of 2 poles. It failed over a week or so, I could
press and latch a few times and it would work, but very scratchy audio.
It's definitely the switch even though it ohms out OK. If I knew which
pair of poles was correct, jumpering it is easy - but no pinouts are
available for this vertical mount in 4 pole, so I don't know which way
is on or off and it's a PITA to disassemble and reassemble to test -
many ribbon cables, screws, pot nuts, knobs, etc. Worse than a laptop!
Closest 2 pole ALPS attached for reference.
If you look at that photo carefully, i would expect that the plunger
moves the sliding switch mechanism, by way of the equivalent of a 45
degree slide motion translator: vertical to horizontal.
Now, presuming that is the case, the 4PDT switch would be exactly the
same, only the horizontal moving bar is larger to accommodate more poles.
That translates to "that switch is moused".
Partial confirmation comes from your observation "It failed over a
week or so, I could press and latch a few times and it would work."


Robert- you are correct. I found an ALPS switch, vertical mount, 4PDT,
almost the same as original. I'm more interested in the pinout than the
switch as I doubt the switch would physically fit (shaft, pins, etc.).
With this data sheet I now have the switch action which is totally
different than a horizontal mounted one (which works like a slide
switch). The vertical switch when pressed pushes the contacts outward,
when released, they return. See the GIF and attached PDF.
* I had thought of that possibility, but discounted it due to smaller)
switch actions.

So, now I have the action - I need to remove the old switch and try 4
jumpers in it's place. I also found a schematic on a Nakamichi TA-4
which uses a 4PDT switch in the same "Tone Button" as my receiver,
clearly showing how they bypass the Bass and Treble controls. The part
numbers are different but the circuit is almost the same. Thanks for
your explanation!
Rob

Glad that you have the puzzle resolved; a viable schematic, and found
a (theoretically) replacement switch.