Conn 651 Theater Organ Restoration Project

On Hold...

Tue, 20 Jul 2010 12:11:10 -0600

As you’ve probably noticed, it’s been over a year since my last blog posting. I didn’t give up on this project, but life has a tendency to get in the way sometimes. Several life changes have forced me to put this project on the back burner until I can purchase a home to house this gigantic instrument. Until then, it remains covered in storage. But I can promise as soon as we get a house this project will continue.

The biggest project, I think, will end up being the Leslie 600 speakers, rather than the organ itself! I pinpointed the Leslie rotor motor problems to the amp rather than the motors, which makes things a whole lot more complicated. I found several failed components inside the amp, but even after replacing them with good ones (carefully following the service schematic), the motors still refuse to switch over to high unless I “force” the reed switches to engage with a magnet. There are so many potential points of failure, it will probably take me quite awhile to figure it out.

I continue to think big, and that includes plans for a second (yes, SECOND) Leslie 600 cabinet at some point. I envision the main console with a Leslie 600 on either side. I already found the required power relay unit in order to power both speakers, now all I need is a second model 600, and getting the first one to work! Hmmm, this could take awhile...

Leslie 600 Speaker Cabinet

Sun, 5 Apr 2009 22:40:41 -0600

I've always wanted to own a Leslie cabinet, but most of the vintage Leslies are of a massive size with a price tag to match. Recently, I learned about the relatively obscure Leslie model 600 made for multi-channel organs. It's in a fairly compact "low boy" / “decorator” cabinet (wide as opposed to tall). It has six speakers for the various voices, including the trademark treble horn and bass rotor. It also has a built-in tremolo unit and space generator. These were introduced around 1971, right before the Conn 651 in 1973.

I loved the idea of having dual Leslie rotors (both internal and external) for my Conn, so I decided to pick one up. There was one for sale in Los Gatos in northern California, complete with the Conn connector kit. Getting to the location was an unexpected adventure—it was located up in the mountains a couple miles back on a dirt road. The cabinet itself was intact but had surely seen better days. It had been stored outdoors, so the woodwork was dull and faded, and the speaker grill fabric had snags and water damage along the bottom.

When I got it home and opened it up, I found a few more issues: the treble horn needed to be reseated, and neither of the rotating motors (bass and treble) would run at all. It also needed a really good cleaning both inside and out.

On the plus side, it's a good speaker that shows promise. I wasn't sure if I would like the "multi-rank" effect of the space generator, but it turned out to be quite a cool sound. The tremolo unit seems unnecessary, since the Conn 651 has its own.

The condition of the cabinet didn't really live up to the seller's description, but I'm confident that after a good cleaning, lots of lemon oil and some maintenance (and oiling) of the motors, she will look a lot better!

Click here to view pictures of the Leslie 600.

Cleaning the Switch Contacts

Sat, 21 Mar 2009 23:30:33 -0600

Of the 33 rocker tabs and 19 thumb pistons on the organ, several of them had problems. The switches would either not engage at all, or they would require some serious “coaxing” (i.e. wiggling, punching, rocking back and forth). After reading some posts on the Organ Forum recommending CAIG Laboratories’ wonder contact cleaner DeoxIT, I decided to give it a shot.

After disassembling all of the switch assemblies and spraying them with DeoxIT, the contacts were definitely improved and the switching was much more reliable. This stuff really works!

See all photos from the contact cleaning process.

Piston Pilot Lamp Replacement

Sun, 15 Mar 2009 17:30:45 -0600

Two piston preset pilot lamps were burned out (Great manual #2 and #4), so I decided to go ahead replace all 17 at once. It’s a good thing I did, because the wire leads were very corroded and probably wouldn’t have lasted much longer. The old bulbs had wire leads coming out the sides, whereas the new bulbs (#2102) had leads coming out the bottom. I also coated the wire leads with WD-40 to help protect against future corrosion, and installed them a little higher off the circuit board to bring them closer to the jewels (and hopefully make them shine a little brighter than the old ones.) While the bulbs were out I went ahead and removed the jewels to polish them and remove as much rust as I could. I was very pleased with the results!

Click here to see all the photos.

Main Amp Replacement

Sat, 28 Feb 2009 16:45:12 -0700

The biggest issue with this Conn 651 was with the voices: only the Tibias and Vox Humana voices were working, and nothing else. The organ was crippled for years. The previous owner described what sounded like an “explosion”, and nothing worked right after that.

Well, after carefully studying the schematics in the service manual, it appeared that the main amp was the culprit. The Conn 651 has a 2-channel amp: one channel controls the Tibia voices, and the other channel controls the Complex voices (i.e. everything else). Now, to fix it or find a replacement...

A replacement from the Organ Service Corp would run me $900 bucks. No way THAT was gonna happen, so off to eBay I went. Well, as fate would have it, there was the exact amp model I needed in working condition for $50! Sold! I hooked it up, plugged it in, and... SUCCESS! She was singing with all voices once again!

Now that the biggest issue is out of the way, I can focus on the myriad of other ones. Stay tuned! And if you haven’t already, check out the Conn 651 Photo Album.