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Electronics => Projects, Designs, and Technical Stuff => Topic started by: mkiijam on February 17, 2024, 01:29:05 am

Title: What is this strange device I see? When I touch it, it gives forth a sound???
Post by: mkiijam on February 17, 2024, 01:29:05 am
This strange thing is in an Acetone Drum machine from the 60's[attachimg=1]
Title: Re: What is this strange device I see? When I touch it, it gives forth a sound???
Post by: ataradov on February 17, 2024, 01:49:18 am
Likely a transistor. Probably a FET of some sort, they came in funky packages like this.  Later high frequency devices were packaged in a similar way, but if it is 60's, I doubt it is anything special.

RF amplifiers are also commonly packaged like this, but I see no reason for that in a drum machine. And the rest of the design is clearly far from RF.
Title: Re: What is this strange device I see? When I touch it, it gives forth a sound???
Post by: mkiijam on February 17, 2024, 02:02:20 am
It's possible it is [attachimg=1]TR1
Title: Re: What is this strange device I see? When I touch it, it gives forth a sound???
Post by: ataradov on February 17, 2024, 02:10:26 am
If two pins go to a transformer and the other one to a variable resistor, then yeah. So, it is just a regular BJT.
Title: Re: What is this strange device I see? When I touch it, it gives forth a sound???
Post by: moffy on February 17, 2024, 02:48:54 am
Looks like a VHF transistor I once tried to use for a fibre optic amp at University using someone elses SPICE design, it was unconditionally unstable.
Title: Re: What is this strange device I see? When I touch it, it gives forth a sound???
Post by: moffy on February 17, 2024, 03:34:49 am
A smaller version of this: https://www.time-tunnel.com.au/electronics/spare-parts/transistors/motorola-hf-rf-power-transistor-mrf421-100w/ (https://www.time-tunnel.com.au/electronics/spare-parts/transistors/motorola-hf-rf-power-transistor-mrf421-100w/)
The case is possibly beryllium oxide and toxic in dust form.
Title: Re: What is this strange device I see? When I touch it, it gives forth a sound???
Post by: MarkT on February 17, 2024, 10:37:36 am
Looks like a dual-gate MOSFET - can be used for ring modulation which might have a role in a drum machine.  The white body may be beryllia (toxic dust hazard) or alumina, indicating its an RF device.