Ondrej Pavelka

#82826

Hi folks,?

I normally fix synthesisers? and sometimes the odd Rhodes Wurlitzer Pianet or Clavinet. When it comes to Hammond's I have dealt with T200 and L100 successfully.?
The thing is I have tiny workshop and now I'm asked to figure out the hum problem with B3 and L122 cab. To be fair I can't realistically imagine moving the B3 with Leslie 122 to my workshop for troubleshooting.?
I'm based in Europe and the hum is 50+100+150 Hz so clearly it's either grounding issue or PSU filtration issue.?

I don't have spare "Leslie" connector to make a dummy cable and fire up the speaker on it's own. I suspect the Leslie more then the B3 itself is the problem.?

How would you triangulate the issue if you were me??

#82827

开云体育

Probably someone else will offer a better suggestion but I would start by removing the wires from the 2 “G” terminals on the ?preamp in the organ. That is the signal output from the organ. With both of those disconnected, if the same hum is there it would be in the Leslie amp and likely the can capacitor.

?

Rich Reid

208-861-9263

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Ondrej Pavelka
Sent: Thursday, January 28, 2021 3:51 PM
To: [email protected]
Subject: [hammondzone] B3+122

?

Hi folks,?

I normally fix synthesisers? and sometimes the odd Rhodes Wurlitzer Pianet or Clavinet. When it comes to Hammond's I have dealt with T200 and L100 successfully.?
The thing is I have tiny workshop and now I'm asked to figure out the hum problem with B3 and L122 cab. To be fair I can't realistically imagine moving the B3 with Leslie 122 to my workshop for troubleshooting.?
I'm based in Europe and the hum is 50+100+150 Hz so clearly it's either grounding issue or PSU filtration issue.?

I don't have spare "Leslie" connector to make a dummy cable and fire up the speaker on it's own. I suspect the Leslie more then the B3 itself is the problem.?

How would you triangulate the issue if you were me??

#82828

开云体育

All,

To determine if it’s the organ, you can attach headphones to the GG outputs. The signal is hot enough to drive them, and you can see if you hear hum with no Leslie attached.?

Next, while you can remove the wires from the GG terminal while the Leslie is plugged in, you can achieve the same (maybe better) result by shorting the GG terminals together. ?This will eliminate any signal from the Leslie input, and you can then see if the hum is because of failed filter caps in the Leslie. If you remove the wires from the GG terminals, there is possibility of picking up hum since the input wires of the Leslie would then be unattached to anything.?

If you find electrolytics have gone bad in either the organ or the Leslie, I would strongly recommend replacing all of them. (Assuming they are all the same age).?

Good luck,

Jim G

On Jan 28, 2021, at 5:55 PM, Ondrej Pavelka <info@...> wrote:

?Hi folks,?

I normally fix synthesisers? and sometimes the odd Rhodes Wurlitzer Pianet or Clavinet. When it comes to Hammond's I have dealt with T200 and L100 successfully.?
The thing is I have tiny workshop and now I'm asked to figure out the hum problem with B3 and L122 cab. To be fair I can't realistically imagine moving the B3 with Leslie 122 to my workshop for troubleshooting.?
I'm based in Europe and the hum is 50+100+150 Hz so clearly it's either grounding issue or PSU filtration issue.?

I don't have spare "Leslie" connector to make a dummy cable and fire up the speaker on it's own. I suspect the Leslie more then the B3 itself is the problem.?

How would you triangulate the issue if you were me??

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#82829

Just short out the G-G terminals and see if the hum goes away.? If it does then the Leslie is not the? problem. It's the AO28 preamp. Start with the filter caps on the power supply.

Jay Terleski

Array Solutions
214 954 7140

Show quoted text

On Thu, Jan 28, 2021 at 5:43 PM Rich Reid <[email protected]> wrote:

Probably someone else will offer a better suggestion but I would start by removing the wires from the 2 “G” terminals on the ?preamp in the organ. That is the signal output from the organ. With both of those disconnected, if the same hum is there it would be in the Leslie amp and likely the can capacitor.
?
Rich Reid
208-861-9263
?
From: [email protected] [mailto:[email protected]] On Behalf Of Ondrej Pavelka
Sent: Thursday, January 28, 2021 3:51 PM
To: [email protected]
Subject: [hammondzone] B3+122
?
Hi folks,?

I normally fix synthesisers? and sometimes the odd Rhodes Wurlitzer Pianet or Clavinet. When it comes to Hammond's I have dealt with T200 and L100 successfully.?
The thing is I have tiny workshop and now I'm asked to figure out the hum problem with B3 and L122 cab. To be fair I can't realistically imagine moving the B3 with Leslie 122 to my workshop for troubleshooting.?
I'm based in Europe and the hum is 50+100+150 Hz so clearly it's either grounding issue or PSU filtration issue.?

I don't have spare "Leslie" connector to make a dummy cable and fire up the speaker on it's own. I suspect the Leslie more then the B3 itself is the problem.?

How would you triangulate the issue if you were me??

#82830

开云体育

Starting at the Leslie and working backwards, some simple checks. First, turn the volume control on the Leslie down, if the hum disappears with the organ sound, the fault is probably in the organ, if not the fault must be in the Leslie. Second, do any of the organ controls affect the hum? Specifically, swell pedal, volume soft tab, vibrato controls, if any of these affect the hum this may give a clue as to the cause. Lastly a not uncommon cause but one that often puzzles players and technicians, is the Leslie near the left hand end of the organ? There is an audio matching transformer at the left hand end of the keyboards, if the Leslie is placed near this, it can pick up the magnetic field from the Leslie motors.

On 28/01/2021 22:50, Ondrej Pavelka wrote:

Hi folks,?

I normally fix synthesisers? and sometimes the odd Rhodes Wurlitzer Pianet or Clavinet. When it comes to Hammond's I have dealt with T200 and L100 successfully.?
The thing is I have tiny workshop and now I'm asked to figure out the hum problem with B3 and L122 cab. To be fair I can't realistically imagine moving the B3 with Leslie 122 to my workshop for troubleshooting.?
I'm based in Europe and the hum is 50+100+150 Hz so clearly it's either grounding issue or PSU filtration issue.?

I don't have spare "Leslie" connector to make a dummy cable and fire up the speaker on it's own. I suspect the Leslie more then the B3 itself is the problem.?

How would you triangulate the issue if you were me??

--

Virus-free.

#82831

开云体育

Starting at the Leslie and working backwards, some simple checks. First, turn the volume control on the Leslie down, if the hum disappears with the organ sound, the fault is probably in the organ, if not the fault must be in the Leslie. Second, do any of the organ controls affect the hum? Specifically, swell pedal, volume soft tab, vibrato controls, if any of these affect the hum this may give a clue as to the cause. Lastly a not uncommon cause but one that often puzzles players and technicians, is the Leslie near the left hand end of the organ? There is an audio matching transformer at the left hand end of the keyboards, if the Leslie is placed near this, it can pick up the magnetic field from the Leslie motors.

On 28/01/2021 22:50, Ondrej Pavelka wrote:

Hi folks,?

I normally fix synthesisers? and sometimes the odd Rhodes Wurlitzer Pianet or Clavinet. When it comes to Hammond's I have dealt with T200 and L100 successfully.?
The thing is I have tiny workshop and now I'm asked to figure out the hum problem with B3 and L122 cab. To be fair I can't realistically imagine moving the B3 with Leslie 122 to my workshop for troubleshooting.?
I'm based in Europe and the hum is 50+100+150 Hz so clearly it's either grounding issue or PSU filtration issue.?

I don't have spare "Leslie" connector to make a dummy cable and fire up the speaker on it's own. I suspect the Leslie more then the B3 itself is the problem.?

How would you triangulate the issue if you were me??

--

Virus-free.