I Love Workin' on Old Stuff

[<JAMESEO@aol.com>]

I started out as an electronic technician in the Air Force during 
the Viet Nam era, working mainly on vacuum tube-based radios, with 
some solid state digital gear thrown in for good measure. Back then, 
of course, solid state circuits differed from tube circuits in that 
they were transistors 'n' stuff mounted on a printed circuit board 
as opposed to tubes, wires, caps, resistors, and other parts mounted 
to a cassis as we all know and love in our Hammonds. After that, I 
went to work for "a large Beaverton-based electronic test and 
measurement instrument manufacturer" (look at the name plate on your 
blue 'scope), where, more and more, IC's and other magic were the
order of the day.

Man, am I glad to have come back "home" with my M3/21H!

Had a gig Saturday night, and after I had made the organ-to-Leslie 
connections and fired 'er up, I was met with an interesting problem: 
the upper manual had no main tone, but it did have just the harmonics 
when percussion was turned on. The lower manual had main tone, but not 
when vibrato was turned on. Also, the rocker switch for the upper manual 
vibrato would not "snap" into position, either on or off. It just sat 
there in-between states. Hmmm, says I. Well, it's a good thing I had 
the ol' Ensoniq KS-32 along to pinch-hit for the Hammond sounds, because 
in a case of brain-fade, or perhaps just feeling lucky, I had neglected 
to make sure my schematics and tools were along for the ride, but I did 
have a screwdriver, so I was at least able to pop off the cover for the 
manual connections to the amp (A & B) and verify that it wasn't something 
simple like a broken connection. No such luck, and I didn't have enough 
time for further investigation, so I just used the KS-32.

Meanwhile, this afternoon I had a chance to troubleshoot. Went straight 
for the upper manual vibrato switch, since it obviously needed looking 
at, anyway. Sure enough, that little spring clip thingy that holds the 
switch in one position or the other had somehow come off its mount point and
had bounced around in the switch bank box during transport and had 
come to rest across a couple of connections in there, thus causing the 
symptoms. If this had been a modern keyboard, like the KS-32, with its 
IC's, and everything mounted directly to one or two circuit boards, I
wouldn't have even thought of troubleshooting it myself, except perhaps 
to look for bad solder joints, etc. Besides, with silicon, something 
would probably have fried, anyway. But since this is good ol' wires 'n' 
tubes 'n' stuff, I dove right in with confidence that it was unlikely 
any real damage had occured. Piece of cake. Like I said, it sure is good 
to be back "home".

- Jim

P.S. The schematics and tools are coming along from now on, too :-)

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| Jim Ormond             Sailor, motorcyclist, musician;  How DO I     |
| 5484 SE Drake Rd.      find time for serious stuff?  Hey, wait a     |
| Hillsboro, OR 97123    minute! That IS my serious stuff!             |
| jameseo@aol.com                                                      |
| http://members.aol.com/jameseo/jimHome.html                          |
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