Hammond M3 repair chaos

MechaGodzilla · Post by **MechaGodzilla** » Sat Mar 04, 2006 11:09 am

Heyo-

So I have this really bitchin' Hammond M3 that I got for free off of Craigslsit. It fires up alright and the motor spins fine, but the actual organ sound is incredibly low-volume (Like, barely audible). However, the percussion still bleeps away at full volume, so I know the amp is working.

After looking at the schematic my best guess is that the matching transformer is shot. Any other ideas? Is this a common M3 problem?

Anyway, if it's junked, at least it didn't cost anything.

Scodiddly · Post by **Scodiddly** » Sat Mar 04, 2006 11:31 am

You've got some drawbars pulled out and the appropriate preset key down, right?

Not sure where my Hammond binder is located, but I could dig it up. I don't know that I'd start by blaming the matching transformer, though. Probably any capacitors (except ceramic disc types) are worth replacing.

Milkmansound · Post by **Milkmansound** » Sat Mar 04, 2006 12:24 pm

what about the tubes? Those don't last forever either...

MechaGodzilla · Post by **MechaGodzilla** » Sat Mar 04, 2006 9:05 pm

Yep, the drawbars are pulled out, and they do affect the sound.

You know, I haven't even checked the tubes. But would a bad tube make it quieter? I figured a bad tube would just sound cruddy.

Milkmansound · Post by **Milkmansound** » Sat Mar 04, 2006 11:08 pm

check the tubes.

Scodiddly · Post by **Scodiddly** » Sun Mar 05, 2006 5:22 am

I found my binder, and I don't have an M3 schematic! Grr...

Anyways, if it's anything like the B3 there's still maybe a tube stage or two between the the matching transformer and where the percussion signal gets mixed in.

MechaGodzilla · Post by **MechaGodzilla** » Mon Mar 13, 2006 12:01 am

So I found a PDF of the schematic here... Anything in there look like a potential culprit?

Scodiddly · Post by **Scodiddly** » Mon Mar 13, 2006 5:35 am

Point "D", right there in the middle, is where everything gets mixed together. Since there are separate matching transformers and preamp sections for upper & lower manuals and the pedals, you might check all of those to see if any work. Also try with the vibrato on, since that's a separate preamp path as well. The previous owner may have just lived with one dead section after another until only the percussion worked, and then sold you the organ.

tonewoods · Post by **tonewoods** » Mon Mar 13, 2006 9:02 am

Well, the M3--even when things are working right--isn't all that loud to begin with....

I'd get ahold of a Leslie to make that M3 sound the way it should...

Here's some info on how to go about doing that.
It's not that difficult....

Luck!

MechaGodzilla · Post by **MechaGodzilla** » Mon Mar 13, 2006 11:24 am

Well, both manuals still have the same problem (sound is nearly nonexistent), both with or without the vibrato on.
Hey, here's a clue - The previous owner robbed the bass pedals from this one to fix up his main organ - So instead of having pedals, it has a nice piece of wood for your feet. I've never turned the organ upside-down, but could something have been severed when he took the pedals?

Scodiddly · Post by **Scodiddly** » Mon Mar 13, 2006 8:18 pm

MechaGodzilla wrote: I've never turned the organ upside-down, but could something have been severed when he took the pedals?

Shorted, possibly. But only the lower partials, you should still get the right high partials. And if the percussion still works... maybe the guy took a tube or two as well?

Scodiddly · Post by **Scodiddly** » Mon Mar 13, 2006 8:21 pm

Looking at that schematic again...

Both manuals go through the part labelled "manual amplifier". I'd definitely spend some time on that part of the preamp, since it's before the "D" point where the percussion gets mixed in.

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Hammond M3 repair chaos

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