Optigan schematics

yes its true, a service manual *still* exists

• 34001 (in .pdf format)
• 35001 / 35011 / 35012 (in .tif format)
• 35002 / 37003 (in .tif format)

You will be able to purchase a cd rom of the service manual on our Shoptigan page but at this point we’re still working on it, so enjoy the schematics for now!

Optigan Audio-Output Mod

Here’s a freebie from the Service Manual – it’s instructions on how to modify the outputs on your Optigan to be more suitable for recording and amplifying.

Optigan Audio-Output Mod [pdf]

Why are Optigans so unreliable?

The design team for the Optigan largely came from a toy manufacturing background, and consequently most of the engineers thought purely in mechanical terms. There were many elements of the Optigan’s design that could have been much better handled using electronic parts and transistors (such as the disc drive system), but even after designing and patenting some technically superior electronic designs, the engineers nevertheless chose to go with mechanical means instead. This combined with the fact that the target price had to be kept reasonable meant that the Optigan suffered from a pretty flimsy design, by musical instrument standards.

How do I dismantle my Optigan for repairs?

The quick and dirty answer to this question is: just get in there and start unscrewing everything in sight!! While it can be a time consuming process, Optigans are not that hard to take apart and your intuition should guide you pretty well. Since disassembly varies for the different Optigan cabinet designs, I’m hesitant to try to write down step-by-step instructions on how to dismantle each kind of Optigan. But eventually I’ll have a .pdf version of the Optigan Service Manual available for purchase, which has lots of great exploded view diagrams to guide you through the process.

Some of the chord buttons on my Optigan don’t work. How do I fix this?

Usually this problem can be cleared up by getting into the contact board and using a pencil eraser to “erase” all the gunk and oxidization from the contacts. This process is actually very easy- it just takes awhile to gain access to the contact board itself. Sometimes the problem remains no matter how much you manage to clean your contacts. In this case, usually you’ve got a bad photo-cell, and there’s not really anything you can do.

Some of the keys on my Optigan don’t work. How do I fix this?

Often this problem can be cleared up by pressing the keys quickly and repeatedly. If this doesn’t work, you might try getting inside the thing and cleaning any gunk that may have gotten in between the rubber contact strip and the metal contact plates. I’ve also had good luck by simply turning the rubber strip over. It’s a bit difficult to remove and replace the strip, but I’ve done it successfully several times. In extreme cases, the rubber strip may need to be replaced, though I have yet to find a source for an exact match for these strips.

When I play the top most key on my Optigan, I hear one of the chord tracks bleeding through. What’s wrong?

Crosstalk! Learn to live with it! If you don’t have the test discs, the easiest way to hear the crosstalk is by pressing the top most key on the keyboard. Crosstalk changes with the weather, basically- the light detector is very sensitive to temperature and atmospheric changes. The result is that adjacent tracks on the disc will bleed into each other. The top most key on the keyboard lies right next to one of the chord buttons, so usually you will hear that pattern bleeding through. The test discs were designed primarily to measure how much crosstalk you had on your optigan, but they weren’t much help in alleviating the problem!! Interestingly enough, I’ve found that in the Southern California climate, I can usually clear up crosstalk problems by leaving an Optigan in the trunk of my car for a day or so. (Basically this discovery was a fringe-benefit of laziness!!!) The bottom line is this: with an Optigan, your best bet is to simply wait a day or so until the problem magically disappears. Attempts to re-align the light-detector usually prove to be a frustrating waste of time, and often you will end up making matters worse by fiddling with it. When the Orchestron was designed, special attention was paid to the crosstalk problem, resulting in a more musically sensible track layout on the discs and a more easily adjustable light detector. But with the Optigan you’d better start getting used to the sound of your melodies played as parallel minor seconds!!

How do I clean my Optigan discs?

It’s largely a futile effort, because the scratchiness is mostly caused by actual scratches on the discs, but if you really want to clean them, DON’T use water! Go out and buy some film cleaning fluid from a camera store. Keep in mind even a mint Optigan disc sounds pretty bad right out of the shrinkwrap!! If you don’t believe me, just order a copy of “The Joyous Sounds Of Christmas: Johnny Largo At The Optigan” to hear the absolute best-case-scenario sound quality that the Optigan ever produced!

My Optigan is making a knocking or grinding noise. What’s wrong?

Chances are, there’s a small divot cut into your idler wheel. As the wheel goes around, it makes a knocking noise every time the divot hits the drive shaft. This is fairly easy to fix. If you remove the idler wheel (that’s the black, hard rubber one) and fill the divot with super glue, you can later sand it down to be equal with the edge of the rest of the wheel. I’ve had good luck with this process. If you don’t trust yourself to do the job, you can always simply have the idler resurfaced (see above), which probably needs to be done anyway.

The “A Major” and “E Major” buttons on my Optigan sound wrong. Are they?

Yes and no. From a musical standpoint, they’re very VERY wrong! But nothing is actually wrong with your Optigan. In order to fit enough stuff onto the discs, they had to cut corners a bit. There wasn’t enough room for A and E major, so they decided that they would take a C# dim chord (which has a couple of notes in common with A major) and use that for multiple chord buttons. Similarly, a G# dim serves as the E major. The best way to bolster the tonal implications of these chords is to back them up with full-fisted majors on the keyboard. Even then, you’re still only getting dominant 7ths with the third in the bass!

Is it possible to install a more stable drive system in my Optigan?

Probably not. Mattel patented a better drive system for the Optigan, but you’d have to build the thing up from scratch in order to implement it. It’s based on a belt driven, electronically controlled system as opposed to an electro-mechanical system. The Chilton Talentmaker and the Vako Orchestron both feature a more reliable direct-drive system.

My Optigan makes a lot of buzz and hum. What’s wrong?

Basically, you’re going to have to face the fact that the Optigan is inherently a very buzzy, noisy machine. Unless you want to completely replace the grounding and amplification system, your only hope is to try to minimize the buzz and maybe notch it out with a multi-band EQ or some noise reduction DSP. The first thing you can do is try reversing the way the power cord is plugged into the wall socket. In fact, there’s a sticker on the back of every Optigan which tells you to do this. Find the polarity that gives you the least amount of buzz. In a reverb-equipped Optigan, you have another problem to surmount. If the foam insulation has eroded away from the chord button contact area, you’ll get a nasty buzz as your hand gets closer to the buttons. I’ve yet to find a suitable replacement insulation, but I’m sure there’s something out there that will do the trick.

The overall volume seems a bit weak. What can I do?

Attached to each amplifier is a little trimpot for adjusting the chord/keyboard volumes. On most Optigans, these trimpots can be accessed by the little holes on the back of the unit. If you still can’t get much sound out of an amp, or the sound is particularly distorted, the the amp has gone bad and would ultimately need to be replaced. If you’re clever with this sort of thing, I’m sure it’s very easy to come up with some kind of alterate amplification scheme. Keep this in mind, though, if you plan to switch the chord/keyboard amps around: The only difference between the two amps is the presence of a small jumper in the lower left hand corner of the amp. Only the keyboard amp has this jumper: the chord amp does not. It’s fairly easy to add or remove the jumper if you decide to switch the amps around.

The little red metronome tab has fallen off my Optigan disc. What should I do to make sure I stay on the beat?

The best way to replace those red tabs is to simply buy a red permanent Sharpie pen and color over the appropriate metronome window. It works fine, and shouldn’t rub off. If you desire maximum redness, try rubbing it on both sides of the disc.

Where do I get a replacement bulb for my Optigan?

The bulb you want is a GE Lighting 48707 40T10/RVLCD1 Tubular Bulb. For those who want to know more about this bulb, here’s the tech specs.

My Optigan has unstable pitch. Is there hope??

Pitch stability is one of the biggest problems for Optigans. The rubber on the idler wheel gets hard or worn over the years, which makes the wheel slip against the tapered motor shaft. Old wheels can have other problems including notches or flat spots, which cause a knocking or grinding sound when the discs are played. I’ve tried to recondition the rubber and restore the gripping surface with chemicals and fine sandpaper, only to have the pitch problems return a few weeks later.

I recently came across the web site of fellow who says that he completely replaces the worn and damaged rubber on pinch rollers and drive wheels in tape recorders. On the site he shows several examples of his work along with a wow and flutter test comparing a repaired pinch roller to a new one. Since his price seemed reasonable and I had a spare idler wheel, I decided to give him a try.

After about week I received the repaired wheel. The wheel was clean and the rubber had the correct wedge-shaped profile (I sent him a copy of the original Optigan blueprint for the idler). I disassembled the Optigan and removed the shaft/wheel assembly only to discover that the wheel is secured to the shaft by crimps on either side of the wheel. I have a small lathe, so I chucked up the shaft and carefully filed down one of the crimps to remove the old wheel. I slid on the repaired wheel after applying oil to the shaft. I then secured the wheel to the shaft with a clip and reinstalled the wheel/shaft assembly into the Optigan.

I tested the wheel using the new Mod Rock disc. It played well and there was no change in pitch during the several minutes of play. I then put in an old Optigan disc that used to slip badly, and the pitch stayed stable like the Mod Rock disc. I then replaced the Mod Rock disc and played with the pitch control. I was amazed to discover I was able to adjust the pitch about 10% lower and higher than before. I’ve had the Optigan working for a week now, and it’s holding up nicely. I’ll publish an update in a few months. I am optimistic that this will hold up for many years.

The fellow’s name is Terry Witt and the web site is www.terrysrubberrollers.com. The charge for rebuilding the Optigan idler is $35 plus shipping ($5 for the USA). I have been discussing the possibility of Optigan owners sending in the wheel/shaft assembly without having to go through the difficultly of removing the wheel from the shaft. He is willing to look at this and he’ll need to see one to determine what is involved (may or may not affect the price).

If you intend to send your wheel to Terry and you’ve never disassembled an Optigan, you may want to pick up a copy of OptiDocs from Optigan.com for instructions. Let us know if you use his services, and please post your results.

Robert

Robert’s Tips for Teens #1: Litho Tape for Metronome Windows

Robert Becker, the genius who worked out the software for generating new optigan disc images from digital audio files, has a couple of optigan restoration tips, so I thought I’d post them as blog entries.

If you have Optigan discs that are missing the little red piece of tape that goes over the downbeat metronome window, get yourself a roll of 3M Highland 616 Lithographers Tape. It’s the exact same tape used on the original Optigan discs.

Robert’s Tips for Teens #2: Silver Highlights on Optigan Logo

Robert sez:

I went to Michael’s Craft and Floral to see if they had stuff to replace the silver highlights on the Optigan metronome logo I got from you. After looking at all the silver leaf options, I asked a couple of store employees what would work best. We narrowed it down to “Rub-N-Buff” and a Krylon silver leafing pen. After some experimentation, the silver leafing pen was astonishingly good. My worries about it being dull like a silver colored Sharpie evaporated when I applied it to the raised portion of the logo, and the sliver looked as bright as a freshly chromed bumper.

When I got home I spent about five minutes carefully applying the leafing. I fixed small flubs with the tip of an Xacto blade dipped in rubbing alcohol. I’m amazed at the results; looks just like new!

This one could use new silver leafing!!

OptiDocs now updated with Talentmaker & Orchestron Docs

This is just a quick note to let y’all know that the OptiDocs service manual CD-Rom has now been updated to include the impossible-to-find Talentmaker service manual as well as Orchestron service docs, schematics, and brochures. 275mb of geeky goodness. Order your copy today!

OptiDocs now updated with Talentmaker & Orchestron Docs

This is just a quick note to let y’all know that the OptiDocs service manual CD-Rom has now been updated to include the impossible-to-find Talentmaker service manual as well as Orchestron service docs, schematics, and brochures. 275mb of geeky goodness. Order your copy today!

Robert’s Tips for Teens #3: Optigan Idler Wheel Removal

Removing the idler wheel from the Optigan is a challenge, but can
be done if you are patient and mechanically inclined. If not, you
may want to solicit help from a mechanically savvy friend to work
with you (and share the pain). This will be a learning experience,
and potentially frustrating if you are not careful. Or it could be
a Zen experience that will increase your love and intimacy with
your instrument (but this is very doubtful).

Old Optigans tend to be dirty inside, so protect your floor with a
drop cloth. Make sure you have plenty of light, maybe a flashlight
too.

Since the Optigan I bought from Pea needed some restoration, I've
had it apart several times, so it wasn't too painful for me to
remove the wheel and wheel shaft from the machine. It did take a
few hours.

You may want to get the technical manual CD for your model from
Pea so you know where all the screws are, and the proper order
to remove them. On some models there are a few hidden screws, and
the manual will show these.

One of the biggest challenges you'll face if you've never had your
unit apart is removing the sides (assuming you have one of the
units made of the plastic Temperite material and not the all wood
model). The sides tend to glue themselves onto the main section,
and it can be hell to get them off. You may need a rubber mallet
to separate them after you remove the screws that hold them on.

You'll need small and large size Philips screwdrivers as well as a
slot blade type. Nut drivers or a socket set is helpful, but
remember this is an old American-made product, so the sizes are in
fractions of an inch, not metric (Darn those Americans!)

As you remove screws, I recommend putting them in little baggies
and labeling them so you know where they go, as well as a sequence
number (e.g., "Step 1, back panel screws"). You'll thank yourself
later that you did this. If you take pictures with a digital
camera of each step, you find this helpful as well (and you can
send them to us to upload to the web site to help others!) Take
care not to break wires, and don't use too much force.

I found that I had to remove the electronics on the top of the
chassis to get to the wheel as well as some of the keys on the
keyboard (there are hidden screws underneath some of the keys.) I
had to loosen the motor housing too. In fact, I recall completely
removing the top chassis from the Optigan to get to the wheel.

There is a small spring that goes towards one end of the idler
shaft; note its position and take a picture or make a drawing so
you can reinstall it later.

You have to fish the shaft and wheel out as a unit after removing
the retaining clip that holds the shaft to the mechanism. Don't
attempt to remove the wheel from the shaft. On some units the
wheel is held in place by a clip that is easy to break or lose. In
other units, the shaft is crimped on either side of the wheel,
which would have to be ground down. But removing the wheel from
the shaft should not be necessary because I've talked to the guy
who restores the rubber and he said he would take care of that
part (or at least give it a try). He may charge a bit more if you
leave the wheel on the shaft, so you'll need to inquire with him
directly on price.

While waiting for your wheel to come back, you should clean and
lubricate your Optigan. Use a vacuum to get all the dirt and use
an all-purpose machine oil to lubricate the flywheel shaft and
motor (avoid getting oil on the flywheel rubber). Just a drop of
oil on the pivots and linkages is enough. I washed the keys in the
kitchen sink. 

When you get the restored wheel back, put a drop of oil on the
wheel bearing. Now refer to your notes and pictures and reassemble
your Optigan.

Original Optigan Service Manual on eBay

Hi all, a friend of mine is selling an original copy of the Optigan Service manual on eBay. This is the same manual I sell as a download on this site, though I can’t link you to mine until Shoptigan is back up and running!