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(I'm sorry I have to post in English.)

Hello everyone. I am trying to identify a transistor used in an experimental electronic organ that was built 1956-1961. The builder started with a Conn organ, but I have not yet conclusively identified which model. This transistor seems to be like the 2N269, but the case appears to be bakelite and not metal, and the "hat" definitely has a narrow but distinct brim. There is an orange teardrop shape on the top. I have uploaded the best photo I have of one of these transistors.

[image]

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I have seen them in the 70's , these were American i supose ,These were sold at Tandy/Radio Shack.

--
Cees PA1DBA

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Probably these transistors : type 71226 NPN Si transistors.
[image]
Unfortunately sold.
https://www.ebay.com/itm/276775925599

You could also ask the question on https://antiqueradios.com/forums/
Maybe you can still find them there.

Regards, Armand

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If it really is an NPN silicon transistor you can prolly safely replace it with a BC547B. Or 2SC2240. Verify pinout though.

Tjerk

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Armand: Yes! I haven't been able to see a flat part, but otherwise that is _exactly_ what they look like! Thank you!

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I can confirm that these are exactly the transistors in my electronic organ. They were used in the earliest Conn organs beginning 1965. Thanks, Armand!

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I have some surplus transistors in an epoxy case that look like these. The label on the bag says NPN type 21135.
The print on them is 21335, a logo I don't recognise, a date code 425 and 426.
I put one in the component tester. It is a silicon NPN transistor with an hfe of 450.

Of course, there are many different types sharing the same case. So read the print and test them to know what they are.

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Is there any chance you can take a picture of the logo or describe it?

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Maarten: I have not been able to find any printing on them yet.

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An organ repairman on the organ forum has told me that these are 2N2926. The organ I have is a one-off DIY experimental microtonal organ (19edo) adapted from a regular Conn organ. I still have not identified the Conn model, because my organ uses all transisters (no tubes) and was completed in 1961, and Conn has no listing of using transistors earlier than 1965.

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To avoid confusion, my question was to Onno-I since he mentioned his have a brand logo.

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I’ll dig up my microscope camera tonight.

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A few pics of the print on the transistor. !! these are not the TS's transistors !!
BTW: I misread the production code on one of them. They all carry "426".

[image]
[image]

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the 2N269 was a PNP GE transistor, in metal case.

Since this is a plastic case, which is more common for Si transistors, I would first define if it is a Si or an Ge transistor, easy to do by measuring the EB voltage drop.

I the 50'ies Si transistors where not common, but, the organ might have had rework later on?

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It seems like a transistor from at earliest the 1960's or more likely 1970's. The case may have originated in the US (1960's) and then be used in Asia (1970's), though that's a bit specualtive and based on vague memories.

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kris: I have not yet determined that it is safe to power on this instrument, so I won't be able to do any electrical testing until that is possible.

Please see Armand's comment. I'm almost certain that he has found exactly what these are. I know for sure that the organ was built 1956-1961. It was a modified Conn organ which had these transistors; I'm still trying to identify the Conn model.

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No need to power it on if you want to test whether the transistor is Ge or Si. Just set your multimeter to diode test and measure across the B-E junction. There's a chance it won't work "in circuit" but you'll find out soon enough.

I'd bet it's a Silicium NPN transistor, though. If there's no printing on it, it could even be a hobbyist type from surplus/outside spec stock. Not sure if it's original as 1959-1961 seems ~10 years early. Are you sure the experiments didn't go on for longer or were performed later?

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At the bottom of p 109 in this article, John Chalmers states: "The culmination of Piehl 's work is a 19-tone electronic organ which was begun in 1956 and completed in 1961." This was shortly after he visited Piehl at his home, so that information came first-hand from Piehl himself.

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This list shows some vintage plastic transistors used by Hammond and Conn (circa 1966).
The 2N2926 and the 71226 mentioned in this thread are also included.
The 71226 L4 "orange", likely referring to an orange dot.
https://www.ultraelectronicactive.com/elx/Vintage-Vacuum-Tubes.html

Regards, Armand

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