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Electronics => Projects, Designs, and Technical Stuff => Topic started by: IEvenKnowOhmsLaw on May 27, 2020, 09:41:25 pm

Title: Old Electromyograph Teardown
Post by: IEvenKnowOhmsLaw on May 27, 2020, 09:41:25 pm
I tore down a really old electromyograph I salvaged back in the fall. Unfortunately I've lost a few of the pictures, but here's most of it. I'm particularly curious about the diode packages with the diode symbol on them, I've never seen anything like it. The boards were all the old curvy hand drawn traces, so this would be pretty old. Anyone have a guess on age? 70s? It was all discrete components. Not a single IC by my memory. Could dig the boards out of the salvage pile if necessary.

I kind of regret dismantling it now that I have time, but it was totally dead and old enough to be my father so  :-//
I have about 8 more pieces of old medical equipment if anyone is interested in having a look. Some of it is lab equipment so I'm hesitant to do anything until I know if I could make use of it.
Title: Re: Old Electromyograph Teardown
Post by: BreakingOhmsLaw on May 27, 2020, 10:13:51 pm
Gotta love those bridge rectifiers in the last picture. o_O
Title: Re: Old Electromyograph Teardown
Post by: IEvenKnowOhmsLaw on May 27, 2020, 11:21:50 pm
Yeah, 5 points to anyone who can identify the package on them!
Title: Re: Old Electromyograph Teardown
Post by: BreakingOhmsLaw on May 27, 2020, 11:50:35 pm
Probably germanium. Did you measure the forward voltage?
Title: Re: Old Electromyograph Teardown
Post by: IEvenKnowOhmsLaw on May 28, 2020, 12:00:10 am
~0.55V
Title: Re: Old Electromyograph Teardown
Post by: IEvenKnowOhmsLaw on May 28, 2020, 12:07:44 am
side view

edit: Found a datasheet. Still no idea on the year this would be from
https://www.datasheetarchive.com/pdf/download.php?id=fb211d090c07cacec0de3117f735155eb613a1&type=O&term=SKE4F1%252F02 (https://www.datasheetarchive.com/pdf/download.php?id=fb211d090c07cacec0de3117f735155eb613a1&type=O&term=SKE4F1%252F02)
Title: Re: Old Electromyograph Teardown
Post by: DrG on May 28, 2020, 01:42:15 am
I'm guessing the unit is from the 70s. Who was in White Plains NY at that time? Was Teca?

You may want to ask this guy, he has a small collection http://www.peterbodnarmd.com/museum-of-electromyography.php (http://www.peterbodnarmd.com/museum-of-electromyography.php)
Title: Re: Old Electromyograph Teardown
Post by: IEvenKnowOhmsLaw on May 28, 2020, 02:15:42 am
Yes, it is made by Teca. I'm really suprised someone actually collects these. Thanks for the tip! Compared to his models, mine is closest to the 1960's model. I'll try to get in touch with him.
Title: Re: Old Electromyograph Teardown
Post by: Gyro on May 28, 2020, 11:52:59 am
I see from the speaker mounted by the CRT that it's the 'Machine that goes Ping!'   ;D

https://youtu.be/arCITMfxvEc (https://youtu.be/arCITMfxvEc)


A slightly dodgy place to mount a speaker, even if it is shielded.