Schober Organ Notes No. 84

In the last issue I reported the sad news about Laura Ramsey. Jamie MacKenzie, her friend and executor, was kind enough to send me her obituary which I am printing in this issue. Mr. MacKenzie is busy right now, but he said that he will send me some material on James Ramsey. I have been putting off printing a story about him for some time because I was waiting for more information about him, and will again put off this story for a future edition of our newsletter.

Laura's biting wit, singing and laughter will be missed. Donations in her memory may be sent in her name to any animal assistance organization.

"Alex,

I am a retired Aerospace EE who built a Recital for my church in the late 60s, and I guess I became nostalgic in my old age thinking about that organ. I saw one on the Orphans' Page so I brought it home last year to fool with the circuitry. I can't play a lick but I like the sounds it makes and wanted to keep my brain working and yes, relive that same sense of accomplishment when the Church had its organ. My wife plays the piano a bit so I keep trying to get her interested in it.

The Recital I have now was built in the early 70s by a gentleman named Ashby Lee Coffindaffer of Lost Creek, West Virginia. He was a well organized and careful builder and left copious notes on his progress and problems which he resolved to his satisfaction, all except one that is, the percussion group. My experience with the church organ helped so I now have the entire organ, Reverbatape and speakers back in operation at my home in Wilmington, NC and all is satisfactory except for the percussion section. It seems the gentleman died before he found out what was wrong.

His diagnostic difficulty was caused by the fact that it was not totally dead, you could hear faint sounds like pianos and bells and others things but not very well. After poking around with my oscilloscope I discovered the problem. I couldn't believe what I was seeing on the scope so I checked the copper side of the 11237 board and that confirmed it. Poor Ashby, without realizing it, had fallen victim to a common error which by simple symmetry is a natural mistake to make with a flat sided TO-92 plastic transistor in a flat sided socket. It fooled me for a while.

The diagram shows the correct orientation of a TO39 and a TO-92 in a flat sided socket. Ashby had mounted all the TO-92 transistors with the round side coinciding with the round side of the socket. Poor guy, he never realized he was operating the transistors in the inverted configuration, having inadvertently swapped the emitter with the collector on all of them.

He didn't make this mistake on the tone generator transistors because these little buggers were totally round, there being no flat side on the transistor to tempt him into a lead orientation mistake so they gave him no difficulty. I have just ordered new silicon npn TO-92 transistors to replace all of Ashby's . I'll let you know how things work out if you're interested.

I hope this will be of some help to others out there struggling to get percussion sounds from a PRCN-4 kit."

[In another e-mail Tom added: "One half hour ago I ran across a surprise, another plastic transistor configuration. It is a PNP with the designation 9451 just above ND108. Even though the leads are 'in line' behind the straight edge they follow the TO-92 convention, which is not usual. The supplier at least had the decency to mark the leads: E,B,C, beneath the identification since they were bucking standards. If there are any standards, I'm beginning to doubt it."]

If you download the attached two pictures, they will help explain much of how the procedure is accomplished. You need a strong muscle-type massager like my Pollenex MOD.WM-10 and a 32 oz. spritz bottle with a strong trigger and adjustable spray nozzle (ACE Hardware or equivalent) and a quart can of denatured alcohol to fill the spray bottle. Nothing else should be added to the alcohol. Be careful, though, because alcohol is flammable and burns almost invisibly, so keep any source of ignition away from your work.

I fold the top of my Recital all the way back, supporting it on top of a padded 42" vertical 2x4 positioned in front of the music stand so it won't slip. I then reach in to the top and spray alcohol directly on the bus-bar/spring interface. Don't poke the spray bottle into any thing delicate; you don't have to get that close. You could, if you wanted, remove the voicing cards to improve your view and aim but I don't find that necessary.

I turn on the organ and work one key at a time using different stops. I spray copious amounts of alcohol on the offending bus-bar/key-springs in question, then with my finger partially depressing the key, I listen to the note(s) I get. The vibrator is held against the middle segment of my middle finger, as shown in the picture,[see photo] and by using different vibrator pressure and amounts of key deflection, I can induce the desired vibrations to polish and work the various contact zones. My Pollenex has two settings. I use it on hi and depend on the soft pressure between it and my finger to achieve the vibration I want. You will quickly learn to feel the correct levels of motion induced. It doesn't seem to take long or many re-sprays to clear up a key so the tones return. When the key sounds normally, you can move on to the next key in order. Before you know it, you have a working keyboard.

I hope this helps those with contact resistance troubles, or resistance to contact troubles (pun intended) who are not inclined or thrilled about pulling a keyboard, all those wires, ugh."

***Subscribers to the E-mail version of Organ Notes can get copies of diagrams and photos by sending a SASE and an extra stamp to the editor. Alexander Kruedener (See address at the end of this E-mail)***