Treble only on all octaves, and only with Chorus on

[jrinscheid]

(Newbie poster here)
My Hammond organ is shown as model "BC" on the chassis, with an additional note at the top back that says "This console has been converted to Model BCV". I've got a Leslie 32H Series 3 connected to it.

I hadn't played it in about 10 years, while it sat at my ex-wife's house. Recently I got it moved to my house. Reoiled it and fired it up. Initially no tones - but once the oiled worked in, the gears engaged, and we were back in business.

Sort of.

I ONLY get "treble" out of the organ - doesn't matter which octave I play. The lower octaves on the keyboard, I get a very faint treble, but only treble. Even the pedals (2 octaves) produce only treble.

Further, I get nothing - not even treble - unless the "Chorus" slider is pulled out. With it all the way out, I get a very loud, almost shrill, treble on the upper keyboard, upper keys. It reminds me of the organ at the beginning of Cat Stevens' "Another Saturday Night".

Looking at the back of the Hammond, when you pull the Chorus slider out, it mechanically raises the far left side of the bottom assembly - I believe it is called the tone generators, as it is the assembly that contains the rotating gearshafts. It makes me wonder whether there is a loose wire underneath the tone generator assembly.

The other "diagnostic" I have is that when I touch pretty much any of the metal chassis's in the back, such as the one that the vacuum tubes plug into, I get a fairly loud "thump!" out of the Leslie.

It seems like something is not grounded properly - but would that also account for the lack of any bass at all? And how do I find where something is not grounded properly - where do I look first?

Thanks in advance.

[skydawg]

Safety first...has the mains wiring been replaced?How about the coupling caps in the preamp?There are dangerous voltages present,with 80 yr old wiring and insulation.

[enor]

Are the tone generators actually spinning at the correct speed, or are they still too sluggish? To me it sounds like they might be stopped; and if the generators have been stuck it's quite possible that you've gotten it to the point where the start motor turns the generators over, but when you engage "run" they stall to a halt.

I don't like what you say about the "thump" when touching metal though. This could be a dangerous situation. Get someone knowledgeable to take a look at it.

[Hoaxel]

Bassspeaker in the Leslie out of order?

[Jyvoipabo]

Hello,

I summarize because i don't understand very well.

The organ is connected to a Leslie.
When you play you hear only treble but you can still get a melody.
When you play with the pedals, you hear only treble, while there should not be.

When you touch a metal part inside the organ, there is a noise in the Leslie but you do not get any electric shock.

This may be a problem of bad contact in the connection between the organ and the Leslie.

JP

[jrinscheid]

Jyvoipabo - You summarized very well, thank you.

I checked the connections in the cable between between the organ and the Leslie with an ohmmeter, and have effectively zero resistance from the pin on one end to the corresponding pin on the other end. I took the plugs apart as well, to look for "stray" strands of wire, and they look clean...

Would this procedure have taken care of your suggestion of bad contact between the organ and Leslie?

- - - Updated - - -

hoaxel - Does the fact that I get a pretty pronounced "THUMP!" out of the Leslie when I touch the metal chassis tell me that the bass speaker in the Leslie is working? I did not think to have somebody put their ear near the bass speaker while I was touching the metal chassis - to see if that was the one reacting...


- - - Updated - - -

enor - The bar (shaft?) is still turning after "run" is engaged, with the gears engaged near the motor. I don't know what may be happening inside the various tone generators, as they are on the far side of the metal plate at the bottom of the organ. Does that tell me anything?

And when you suggest I get someone knowledgeable to take a look - am I just looking for a qualified electrician, or a Hammond (or organ) specialist? I live in a pretty rural county, so not sure where to find a specialist. (I'm about 2 hours from Pittsburgh, 3 hours from Philadelphia, Washington DC, and Baltimore.)

- - - Updated - - -

skydawg - I purchased the organ in the 1980s.... I don't know if the mains wiring was replaced before that. Are you talking about the main feeds from the plug that goes in the outlet receptacle (in the wall) up to the chassis with the electron tubes in it?

And when you say "coupling caps", could you say a little more? Are you talking about the capacitors (in metal "cans" on that chassis) or something else?

-------
Thank you all for your suggestions - and looking forward to more! :-)

[David Anderson]

The thump could be from a microphonic tube. Try tapping around with something insulated, like a pencil eraser. The 6SJ7 tubes in CV preamps, which is what is installed in a BCV conversion, are prone to becoming severely microphonic.

At this point in history, both CV preamps and 32H amps need to be thoroughly gone through by a tech. They are 60-70 years old, and you can't expect them not to have problems at that age. You have to reset the clock on components that are likely to fail.

Retrolinear, Tim Warneck's company, is in North Wales, PA, a suburb of Philadelphia.

[enor]

enor - The bar (shaft?) is still turning after "run" is engaged, with the gears engaged near the motor. I don't know what may be happening inside the various tone generators, as they are on the far side of the metal plate at the bottom of the organ. Does that tell me anything?

Both generators though? What you're seeing is just the chorus generator, there's another one if you look deep into the organ. Your problem description seems to indicate that only the chorus generator is running, not the main generator.

[Drawbar Dave]

Both generators though? What you're seeing is just the chorus generator, there's another one if you look deep into the organ. Your problem description seems to indicate that only the chorus generator is running, not the main generator.

As I read through the thread I formed the same conclusion. It sounds like only the chorus generator is working as you only get sound with the chorus drawbar pulled out and the chorus generator only affects the upper octaves.

If you lift the manuals you can see the main generator and its run motor easily.

[jrinscheid]

enor & Drawbar Dave -

You guys called it. When I peer back into the depths of the Hammond, beyond the chorus generator, I can see that the other "gear and shaft" is not engaged and rotating. I can turn it by hand without too much effort (finger tips, as I'm reaching beyond a metal support that has the amplifier chassis mounted to it), but it is much less "free turning" than the chorus generator out front. I would guess if I spun as hard as I could and let go, it might go 3/4 of one more turn. By comparison, the Chorus generator feels like it would go 2-3 turns.

Couple of followup questions:
1) should I be able to see SOMETHING turning out near the bass generator? I can't recall if I could see motor of the chorus generator turning before I freed up the chorus generators with oil, hand turning, and a few days patience.... The bass generator gear and shaft are definitely not turning, but I can't tell if the motor back there is turning - should I be able to see it?

2) what do I do to loosen up the bass generator? I suspect it hasn't been oiled in over 30 years (the chorus generator was probably only oiled 3-4 times in that time)… I put oil in the funnels the second time I oiled the chorus generator, about a week ago. I put some more oil in today... do I just wait a few more days to see if it penetrates? Or turn it by hand more than a few times?

Thanks.
- Jeff R

David Anderson -

I did as you suggested and "tapped" the vacuum tubes with a pencil eraser. All of them generated a little bit of a thump, but one of the two "black" tubes (I didn't pull them out to check the number) - the one deeper in the chassis - produced a notably louder thump.... is that what you were referring to?

Thanks again.
- Jeff R

[jrinscheid]

I CAN SEE WHAT IS/IS NOT HAPPENING ON "BASS" GENERATOR (Sorry for so many posts, and for walking through this one small step at a time.)

With the help of a much stronger LED flashlight, I can now see better what appears to be happening - not sure how to "fix" it.

On the "chorus" generator, when start switch is engaged, the small gear connected to the motor is immediately engaged with the larger gear on the generator. When the run switch is engaged, and the start (after a 4 count) is dropped out, a flat piece of metal pushes the small gear on the motor OUT of the circuit, and large gear on generators continues to turn.

HOWEVER, on the "bass" generator, when the start switch is engaged, the small gear connected to the motor is NOT engaged with the larger gear on the generator. The smaller gear is turning just fine, but is NOT quite close enough to engage the larger gear. I shut things off, put the shaft on the motor "in" such that the small gear is now aligned with the larger gear, but when I push the start switch, it pulls back slightly and is just missing the larger gear.

It feels to me like the large gear/shaft on the "chorus" generator is on some kind of a spring, but I don't get any similar movement on the "bass" generator. Is there a spring there such that I need to "loosen" the "bass" shaft & gear so that the spring can do its job? Or am I imagining such a spring, and the problem is on the motor/small gear assembly?

Thanks again for the continued advice.

(Note to David: I am not ignoring the need to get the power source checked out, to make sure things are safe. I'm just focusing on the tone generators first, since I can see, mechanically, what is transpiring.)

[geoelectro]

The larger gear is supposed to be free to move back and forth easily. A common problem is that gear getting stuck on the shaft and no longer moving or sliding back and forth. In other words, if you push it to the left, it should spring back to the right when you let go. Usually it can be freed up by oiling the shaft and gently forcing it to move back and forth a couple of times. Both generators should work the same way.

Geo

[jrinscheid]

WOO HOO! All generators are now working, and I have a full range of tones on both keyboards! Thanks to all of you - wonderful and clear suggestions. You've all been very generous and kind to this newbie.

There are a couple of other, followup "problems", but I am going to "close" this thread and open them on new threads, since the title of this one no longer fits.

Again, THANK YOU ALL!