Re: Microwave Oven Choke (What's it for?)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>

Greg,

Nice catch! I checked a useful book that I found several years ago:
"Microwave Oven Service & Repair" by Clayton Hallmark (1977) - it's one
of the few books around that gives actual schematics for some of the
older Amana ovens. Some Amana microwaves did indeed use a separate
filament transformer. Specific models shown using separate filament
transformers included models RR-7 and RR-9 (but not sure if the oven you
have is either of these) - I can scan the schematic if you'd like.

Best regards,

-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
Coins Shrunk Electromagnetically!
http://www.teslamania-dot-com

Tesla list wrote:
> 
> Original poster: "Gregory Hunter by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>
> 
> Dear List,
> 
> A friend gave me an old Amana "Radar Range". It
> belonged to his elderly mother. She said it started
> making a scary noise, and she didn't want it anymore.
> It's not just a cliche when I say they don't make them
> like that anymore, because they really don't:
> 
> http://hot-streamer-dot-com/greg/amanal.jpg
> 
> This thing had at least 50 lbs of steel chassis--built
> like a tank. The label says it was manufactured in
> February 1977!
> 
> Getting back to the actual subject--this thing had an
> unusual component in the power supply section--an iron
> core choke. Have a gander:
> 
> http://hot-streamer-dot-com/greg/amanad.jpg
> 
> The rest of the PSU is conventional in every respect.
> Big 2300vac MOT on the left, .85uF/2500wvac capacitor
> with external bleeder resistor, bloc-style HV
> rectifier--the classic half-wave voltage doubler.
> Whatever the choke is, it is involved in the HV
> circuit. The high tension leads for the magnetron pass
> thru it. Oddly enough, I don't see a filament winding
> on the MOT. Could this be a filament xfmr, or perhaps
> a ballast for a 120vac filament? Any appliance repair
> tradesmen out there? What is that thing?
> 
> Regards,
> 
> Greg
> http://hot-streamer-dot-com/greg