Vintage Synth Repair

Here is the content you seek !

Mike

 

Let's start at the 6 pin female socket at the organ.

Looking at the socket you should see a nipple. 

That nipple is between pin 6 and 1.

On the female socket going clockwise is pin 6, 5, 4, 3, 2, 1.

The signal comes out pin 6.

Signal ground is pin1.

One method to connect an A-143 to a Leslie 147 is to tap off of the speaker.

See if you can find a connection to any of the speakers from pin 6.

You can also check the Leslie cable for continuity.

Looking at the 6 pin male Plug with reference to the nipple going clockwise
pin 1, 2, 3, 4, 5, 6.

I'm going to bed. Talk to you tomorrow.

Mike

 

Yep, I have the continuity tester. Where on the organ itself should I test?

I'm thinking that it isn't the Leslie itself that is the problem. When I
turn up the volume, it amplifies the hum just as much as it used to, with
the hum still going away with the volume backed off a few notches.

This is really bothering me since everything worked just fine until I
removed the reverb amp.

Andrew

 

Do you have a continuity meter or a basic signal tracer?

Mike

 

I reconnected the speakers inside the A-143 to see if it would play out. It
has great volume. The problem is between the Leslie itself and the Leslie
output on the organ. 

Maybe somebody could tell me how I could test the Leslie, or some way to
troubleshoot. 

Andrew

 

We need to work backwards from pin 6 of the Leslie cable to find that wire
that is not connected any more.

Mike

 

It doesn't have the ensemble echo switch, but everything worked just fine a
couple days ago. the previous owner cut the speaker leads to kill the
internal speakers. It sounded great through the Leslie. Now, it's all weak.


Andrew

 

Someone could have connected the Leslie wrong to the A143. Did the A143 have
a main ensemble echo switch?

Mike

 

It's a Leslie 147. I'm hoping a re-tube of that will help. I don't know what
happened... I'm not 100% sure it's the Leslie itself.     

Andrew

 

Good ! What model Leslie?

Mike

 

I reconnected the speakers inside the A-143 and found out the problem is
actually the Leslie

Andrew

 

It is a possibility. It is the only thing you removed, right? Did you check
to see if a pin got bent? Was there 1 or 2 wires coming from the socket
adapter? Do you have a digital camera?

Mike

 

I ordered all new tubes for the preamp. Do you think maybe a tube is the
problem?

Andrew

 

Do you have another 12BH7 tube?

Mike

 

Ok. That's what I took out and put the tube back in. There must be something
else that is making the organ sound weak.

I can't figure out what it is. All I did was remove the reverb unit and the
reverb amp. Now the organ sound is weak and kind of distorted.

Andrew

 

That is a socket adapter. It performs the same function as going under the
chassis. Remove this adapter and re insert the 12BH7 tube into the socket.
You should be back to normal operation. 

Mike

 

About this...is there a wire added to the tube socket in the Ao-28 that
needs to come out? Since I took out the Organ Mate reverb, my sound got
really weak. You can barely hear it when the volume is on normal and the
pedal is full throttle. I don't know how to fix it. I don't know what to do

Andrew

 

On an AO-28 Hammond preamp, the usual insertion point is between the wiper
of the tone control and the 12BH7 tube at pin 7. I have the installation
directions if you want them.

Mike

 

Get thee to the "Hammond Zone" group, fellow wheeler.  There are some very
good techs there that may be able to work this out for you.

Kenny

 

I have a Hammond A-143 that I just took the reverb unit out of. It was wired
to the far right 2 of the 4 connectors on the right side of the preamp, and
there was a tube adapter thing that it was also wired to. The tube right
under the tone control knob. I took out the reverb unit (it was not stock,
it's a reverb mate reverb) and I took out the stock reverb amp. there were
only 4 wires connected to it when I got it. 2 of them went up to a box by
the vibrato scanner and the other 2 went to the speaker. I cut those off and
now my organ sound is really weak. I've seen in some pictures of A-100
series organs that there are 2 wires coming down from the right side of the
preamp down to the power amp. Mine doesn't have those wires there. I was
wondering if maybe they were taken off when the replacement reverb was put
in... How can I fix this?? I tried to wire the reverb units back in, but it
didn't change anything

Andrew

 

<snip>
Just as a matter of list etiquette, this sort of a request is considered 
extremely rude.

You post to a mailing list with your question, the rest of the subscribers
on 
the list deserve any replies as much as you do.

Asking that is almost saying that you can't be bothered to read the list for

replies.

Not a big deal to me, overall, but I just figured I'd let you know that this

is a response you may end up getting from some people if you use that 
approach to things...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies.
--James 
M Dakin 

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6:24 PM