332/333 Autoalarm Receiver


Frequency Range: 585 to 615 metres (512 KHz to 487 KHz)


The Marconi Autoalarm consists of receiver type 332, selector type 333, switch type 272, battery charging panel type 242 and three alarm bells.

Type 332 receiver is a combined tuner and amplifier employing three tubes. The first tube, type DER is used as a detector with regeneration. The second tube, also a type DER, is an audio amplifier while the third, type DE7 is used for relay circuit control.

332/333 Autoalarm Receiver Manual  PDF (Courtesy Laval Desbiens via Spectralumni)
The schematics  in the 332/333 manual are tiled. The following handmade  drawings are intended to supplement the above set. Click on the thumbnail to enlarge.
332 auto_alarm_schematic_s..jpg 332 receiver schematic
332_auto_alarm_ext_conn_s.jpg 332 external connexions
333_auto_alarm_selector_s.jpg 333 selector schematic. 
242_battery_charging_panel_s.jpg 242 battery charging panel, 

Contributors and Credits:

1) Spectralumni  http://www.spectralumni.ca/
2) Laval Desbiens <desbiens.laval(at)videotron.ca>

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June 2/19