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THE AM BULLETIN BOARD => Technical Forum => Topic started by: Opcom on March 04, 2019, 05:59:43 PM



Title: Can someone identify this pi coil and switch assembly?
Post by: Opcom on March 04, 2019, 05:59:43 PM
Got it at a hamfest. Wonder what it's from?

Looks like it's good for some juice. I was told it was from a stash of Alpha repair parts, but there are not too many pictures of the insides of non-current-sales-item amps easy to find.

The coil looks to have 8 taps, plus one end. So maybe it's 9 bands? hmm. The switch progressively shorts all of them, so perhaps there was another separate coil as in a 10M coil. No one could tell me any more. The front 'gear' looks more like half of a coupling, and then there is the black toothed pulley. The coil form is nylon or delrin/acetal.


Title: Re: Can someone identify this pi coil and switch assembly?
Post by: Steve - K4HX on March 04, 2019, 10:18:28 PM
The RF deck parts show below were used in the Alpha 86, 89, 91B, 8100, 9100, and 99 and I think on the 89 autotune amp. These used a 4-deck switch. Not sure if this what you have.


Title: Re: Can someone identify this pi coil and switch assembly?
Post by: Opcom on March 05, 2019, 03:20:52 AM
It looks like the wafers are from the same manufacturer and possibly even the same part, but the assembly itself is not the same as in the image or the Alpha manuals I have scoured. There were several of these things on the table, all having two decks. 


Title: Re: Can someone identify this pi coil and switch assembly?
Post by: Steve - K4HX on March 05, 2019, 09:16:11 PM
The band switch parts are all made by Electroswitch.
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