Tone wheel generator removal on a Hammond A-100 Organ?

[stanchfi]

It looks like I need to remove the tone wheel generator from my A-100 (turning the main shaft on one end, does not turn the other end)

It looks to me like removing it involves the below steps
1. Un-solder 150ish connections on the connection bar (red in the photo below)
2. Cut or un-solder 2 wires to the vibrato generator, and 3 wires to the run motor.
3. remove 2 bolts and 4 springs.

Can I disconnect the wiring box on the right hand side near the run motor from the assembly, so I don't have to deal with those wires? (see image below)

Anything I am not seeing, or any advice?

[tmccann]

Your list is partially correct. I wouldn't cut anything, and some wires can be removed from one end or the other. On the vibrato scanner, for example, you can unsolder the wires at the scanner or the line box. I usually do the line box, but either works.

MOST IMPORTANT is to take a lot of pictures. And labeling wires with numbered or lettered tags is helpful before taking the pictures. Something like this works well:

https://www.homedepot.com/p/Gardner-...-035/302444112

For a wires with a lot of terminals, I usually number the terminals left to right (in my head or with a Sharpie) and skip numbers on wires for any terminal that is not used. In the photo above for the TG wires, I would label the first wire as #2, second as #3, third as #5, etc. That way you can't get it wrong going back in,

After labeling and taking pictures, you can do the following:

0) Unplug the organ
1) Unsolder all TG wires (<100, not 150)
2) Unsolder 1-2 wires on right rear of the TG for grounding lug(s)
3) Unsolder vibrato scanner wires at the line box (above the scanner near the top of the organ) or at the scanner itself. You only need unsolder the external wires, not all of them on the scanner
4) Unsolder the scanner shielded wire from the pre-amp, and unscrew the shield as well. You will need to free the wire from the bundle all the way back to the scanner.
5) Unsolder the AC and other external connections to the terminal strip on the left side. You can leave the start motor wires and any other wires, but the AC mains and the wires running up and back to the start/run switches all need to be disconnected
6) Remove the four (not two) TG locking bolts. There are two in the back of organ, and two in the front under the manuals.
7) Remove the four springs. This can be done easier if you lift up the generator a bit to remove some tension on the springs.
8) Carefully examine that there are no remaining wires attached or anything that will snag on the generator. If there are wires in the way, tape them up or down so you have it clear.
9) Carefully lift out the generator, making sure it is not catching on anything. You can do this yourself, but it is much easier with an extra pair of hands!

Make sure you have a cleared area for the generator on a cart, bench, or table before puling it. It's heavy and awkward to handle.

Good luck!

[Sweet Pete]

Make sure the bounce of the springs isn't in play when soldering or working on genny....have it 'bolted down' already off the springs if possible.
Should be step 1A......it's all in the factory service manual,pre 'internet'.

[stanchfi]

Thanks. For the wires, I luckily have access to a laser cutter, so I'm cutting pieces of cardstock to hold most of the wires.
I'm also going to mark any unused terminals with black sharpie


The rest of the wires I will certainty label, as well as take photos of EVERYTHING.
The "I'll remember where it goes" has bitten me in the ass too many times in the past.

Thanks for all the advice!

I'll post an update, hopefully tomorrow

[enor]

The generator harness is laced - there really is no need for any further marking. The lacing clearly shows how it's supposed to connect.

[David Anderson]

Standard practice is to remove the generator with the AC line panel still mounted on the generator after desoldering all power wiring. Desolder the shielded wire from the vibrato scanner at the preamp, which you will have to do to remove the preamp. Note where it is routed. Edit: Forgot this is an A-100, so you don't have to remove the preamp. Still, desolder the scanner coax lead from the preamp.

Desolder all wires. Cutting wires earns you the h-word.

Use care in desoldering the scanner harness from the drawbar base terminals. I've seen lots of them broken/damaged (the terminals). Take careful note of how the scanner harness attaches to the terminals. People often get this backwards in reassembly.

Use a serious temperature-controlled soldering station. A pencil iron will not cut this job. A gun-type iron is clumsy, IMO, and will be too hot to hold by the time you've finished all the harness wires. I know this from experience, which is why I have a soldering station and would never look back.

[Drawbar Dave]

When I do this I remove the start and run switches intact as part of the generator. This way you can fire it up on the bench and check your spin down time before you reinstall everything. It goes without saying that the switches will need to be suitably insulated as they have exposed electrical terminals. I use a plastic hobby box enclosure with two holes cut in it for this purpose.

[tmccann]

When I do this I remove the start and run switches intact as part of the generator. This way you can fire it up on the bench and check your spin down time before you reinstall everything. It goes without saying that the switches will need to be suitably insulated as they have exposed electrical terminals. I use a plastic hobby box enclosure with two holes cut in it for this purpose.

That's a good idea. I did that one time, but wrapped the switches in electrical tape. The box is a way better idea. I've used alligator clips as substitutes, but one wrong move and you've failed the smoke test.

One thing this jogged in my memory is to also wrap some electrical tape around the start motor terminals as they are exposed and live. I've touched them by mistake and got bitten.

[stanchfi]

Well, good news, I got the tone generator removed, thanks to all the helpful advice.
I also found the spring that couples the main shaft. I'm not sure how hard it is going to be to get that back into place.

[stanchfi]

Since I have the generator out, what's the best method to free up the wheels?
None are frozen, but quite a few are gummed up.
Is lighter fluid the best option, or is there something that might work better

I've got my eye on another organ, so I need to get this one up, running and sold as soon as possible, or I will need to look at getting a divorce attorney.

Thanks

[tmccann]

Since I have the generator out, what's the best method to free up the wheels?
None are frozen, but quite a few are gummed up.
Is lighter fluid the best option, or is there something that might work better

What I have done is propped up the tone generator from underneath and with a gloved hand work the wheel pairs back and forth until they move freely. Then with the generator running I use a gloved hand to stop each pair of wheels and that helps free them up also. I do this for each pair until they stop freely with the slightest pressure.

If you have anything particularly stuck, you can spray it with CRC QD contact cleaner through a straw, which is light naphtha. But you have to follow this with a syringe of Hammond oil or the bearings may be squealing. Squealing == damage.

Do not spray oil into the tone generator indiscriminately. I have read multiple posts from experts that the clutches are dry clutches and not meant to use oil.

I have also just recently used a small syringe filled with Hammond oil on an M3 generator and put a drop directly on each bushing for each wheel in the TG. This is easy to do if you stand up the TG vertical or flipped upside down but make sure to secure it. Might be over oiling, but that particular generator runs very quiet and takes ~24 seconds to stop turning when I turn it off.

Lastly, make sure to check both the run motor and vibrato scanner turn easily, and you can use the contact cleaner followed by Hammond oil there also. Consider a vibrato scanner service while it's out of the organ. There are a lot of good links you can google for how to and caveats.

[tiredoldgeezer]

but that particular generator runs very quiet and takes ~24 seconds to stop turning when I turn it off.

That's pretty impressive.
I cleaned-oiled a spinet TWG that i was proud of. Rundown over 20 seconds, but I don't think it made it to 24.

[stanchfi]

Thanks to the wonderful advice, I have the A-100 back up and running great.
Thankfully when I had the tone generator out, I decided to take the cap off the vibrato scanner, and it was pretty gummed up as well, so I took it apart and cleaned and oiled it as well.

Here's a video of my son testing it out - https://www.youtube.com/watch?v=s8HG5rBPJQE

If anybody is interested, he's got it up for sale on Craig's List here - https://tippecanoe.craigslist.org/ms...216265431.html

Thanks again!

[enor]

That's a really cool back panel - haven't seen that design before but I love it!

[stanchfi]

I thought it was a factory option, but I could not find any others like it, so I suspect it is custom, though they did a heck of job matching the stain color.

[KeithB]

Yes, I suspect a custom back also. The factory backs had screws about mid way down that screwed into the TG shelf and obviously looked much different from that one.

[enor]

There's also a version with "church window" shaped openings with cloth inside. I understand it was only available for the A-105 in the US, but in Europe it was also an option for the "plain jane" A-100 (I have it on mine).