Tuesday, October 14, 2008

Bringing in the Hammond

Last weekend, my stepson came over and helped me move the Hammond in from the garage to the new studio space. Before we moved into the new house, it was stored in (climate-controlled) storage, and then it had to wait in the garage for a while. All in all, it hasn't been played in about 2-1/2 years. So there are a few things that need to be done first.

About the organ: It's an A100, one of the spinet styles that Hammond produced mainly for the home market. Despite that, it's a full-up tonewheel organ, with exactly the same layout, sound generation, and controls as the venerable B3. In fact, if you are looking for that B3 sound but find the price tag daunting, you can pick up an A100 and get that exact same sound for $500-1000 less. I don't know why it is that the A100 should sell for that much less than the B3 when they both use the same components. The only difference is that the A100 contains a built-in power amp (two, actually) and speakers, so you don't have to have an external tone cabinet to play it. (Despite that, it does have a socket for connecting a Hammond tone cabinet, or with the proper adaptor, a Leslie.)

The A100 weighs about 350 lbs., and this one has a magnetic attraction for my toes. I actually dropped it on my toes once! So, of course, as we were moving it in, my shoe got stuck in a gap in the floor between the hallway and the room, and it nearly ended up on my toes again. But I eventually got myself unstuck, and now here it resides in all its glory:

Once it was in place, the first step, after a good vacuuming, was to unlock the generator's locking bolts. The generator, and all of the rest of the rotating mechanism, is suspended by a set of springs for mechanical isolation while in use. For transport, it has to be locked down to avoid damage. Here is one of the locking bolts, protrouding from the underside of the generator shelf:

Next step: oiling the generator and motor/scanner assembly. The generator has two funnels on top of it. To oil, fill each one of these funnels with Hammond oil once, and then let it drain. The oil runs into a resevoir and from there to a bunch of little cotton threads which convey it, via capillary action, to the many bearings inside the generator. I don't have a good shot of the funnels (there will be a video of this part up next week), but here is the front of the generator:

The motor/scanner assembly has a little pot on top of the motor which contains a cotton pad. To oil, squirt oil on the pad just to the point of saturation. More will not do any good; it will just wind up all over the place and possibly crud up the contacts of the scanner. Here's a shot; the motor is the square box, with the oil pot on top of it. The scanner is to the left:

Note that this is the run motor. The start motor is at the other end of the generator; it doesn't require regular oiling. However, while I was in there, I put a bit of oil on the mechanism that couples the start motor to the generator shaft. This particular organ has always had a bit of trouble with the start motor not engaging the shaft, and some oil seems to help.

Now, since the organ hasn't been started for a while, I'm going to wait a few days for the oil to propagate through the mechanism. As it happens, I had to go out of town for a few days on business anyway.

The next step was to reinstall the tubes, which I had removed and packed away before the organ was moved from the old house. This organ has a bunch of tubes carrying the Hammond brand. Now, Hammond didn't actually make its own tubes. I'm not sure who made them. They are all noted "Made in Holland". Here's a 6Y5 full-wave rectifier tube, from the reverb power amp:

And a 12AX7 from the preamp:

So when I get back, it will be ready to attempt to start. Before I do that, since it hasn't been on for a while and the filter capacitors are likely completely discharged, I need to come up with a way to limit the power inrush the first time it's turned on. I think I know where I can borrow a variac, but if I can't find one, the backup plan is to plug together all of the long extension cords I bought while were were building the house, about 200' worth, and plug the organ into that. That much wire should do a fairly decent job of limiting the inrush. I'll turn on the run switch for a few seconds, without trying to start it (I'll bet it won't start with that much voltage drop). Then I'll get rid of all the extension cord and attempt to start it.

A few glam shots: Some of the drawbars.

The start and run switches. Older Hammond tonewheel organs have a run motor (the one in the photo above) which is an old-style synchronous motor. It does a fine job of regulating speed once it's started, but it does not have enough torque to start by itself. So there is a second, compound motor which does the starting. It's sort of like starting a car: You switch on and hold the start switch (it's spring loaded) for about six seconds, while the start motor cranks it up. Turn on the run motor, wait a second or two for things to stabilize, then let the start switch go.

Something that a lot of Hammond players don't know about: This is the patch panel that alters the fixed presets (the reverse keys that don't correspond to a set of drawbars). You change them by moving the wires from one terminal to another. Hammond put a paper sticker on the back of the generator compartment cover that explained how. I was surprised to find this still intact when I first took the back off of mine, and I preserved it. I'll summarize it in a post next week. Note the little white cloth sack hanging from the far edge; it contains spare terminal screws. I've got some special plans for this panel, which I will explain in a future post.

1 comment:

Mike said...

Great posting I have a A100 myself