[HAM] Leslie 122 Amp Question

[Jim Shanks]

> At 12:47 PM 6/4/2008, Jim Shanks wrote:
>> > At 10:37 PM 6/3/2008, Jim Shanks wrote:
>> >>Hi All,
>> >>I have a Leslie 122R amplifier that's been subjected to some very
>> >>creative repair.  Looks like whomever fixed it couldn't find the
>> >>30/30/30/10 can cap so they just wired in a bunch of 22mf caps.
>> >>Following the schematics, it looks like one of them is even wired
>> >>wrong.  Plus wires were moved from original locations to accommodate
>> the
>> >>mods and other components a just plain wrong.  Not surprisingly, it
>> >>doesn't sound like it should.
>> >>Anyway, I have the right parts, and service instructions and
>> >>schematics.  What I don't have is a photo of a 122 amp that's put
>> >>together correctly.  A picture or diagram would be real helpful in
>> >>properly placing the correct components as well as getting the right
>> >>colors on the wires.
>> >>Anyone know of a source or have a high res digital photo of the
>> >>underside of a 122 amp?
>> >
>> > Jim, there are a couple of problems with this approach. If this amp
>> has
>> > indeed been modified so irresponsibly, the wire colors could well have
>> > changed. What if, for example,  you were to see an orange wire in the
>> > picture hooked up to C56 +, but the orange wire was now doing
>> something
>> > else? And, no matter how beautifully photographed, I don't think I
>> would
>> > be
>> > at all comfortable with following what I think I see in such a photo.
>> The
>> > only way to wire this amp right, in my humble opinion, is with a
>> complete
>> > understanding of what you see on the schematic.
>> >
>> > The first, and easiest part, is that a terminal trip long enough to
>> hold
>> > the three or four largest electrolytics can have the ground side
>> bridged
>> > across the lugs with grounding wire.
>>
>>Hi Steve,
>
> The name is Scott.
>
>>I don't plan on trying to copy a picture to get mine right
>>except to the extent that I would like the color codes and position of
>> the
>>components to match an original as closely as possible
>
> It won't be easy finding orange or purple wire.
Found orange, I'm color blind, so if there's purple, I thought it was
blue.  :)   I'll ask my daughter to identity the colors for me.  The local
auto parts store will order any color, just takes a couple days.  They had
the standards in stock (black, red, orange, yellow, green, blue, white) 
You're right they don't have purple, but they can get violet.
>
>>the only other thing
>>I see that's out of spec is the DC motor brake circuit was disabled by
>>clipping one lead of the capacitor.
>
> 122s never came with brakes. What's the deal with that???
Maybe "brake" is the wrong term.  Didn't the 122 supply DC voltage to the
motor to slow it down?  Maybe I just read the theory of operation wrong.

>
>>I also noticed that the output tubes, while matched on brand, are not
>>matched.  That doesn't mean they aren't biased correctly, but I doubt it.
>
> Leslie amps are self-biasing; you don't bias them.
That's good news.
>
Thanks for the help.
>
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