[Milsurplus] Waking up Command Receivers

[Jim Whartenby]

AlThere is an error in the power supply schematic.  The Thordarson  number is correct per the schematic but the Stancor number should be P-8609 which is the equivalent to the mentioned 21F82.  The Stancor transformer P-8608 is rated for 600mA at 26.8 volts
Taking a second look at the transformer current requirements, the tube heaters will draw 450mA from the first transformer while the second transformer will draw an additional 650mA if you use the dynamotor rating of 250v @ 70mA.  That is a total of 1.1 amps without looking at transformer efficiency and the heat generated in the second power transformer by the voltage doubler circuit.  So perhaps the first transformer should be rated for a current of 2 amps at 26.8 volts?  The first transformer would run a lot cooler with the ability to source more current.
Mounting transformers close together like shown will cause them to be magnetically coupled.  Perhaps a non issue for a power supply.  Audio transformers and power supply transformers will of course talk to each other if mounted as shown.  There will be a hum in the speaker which cannot be cured by installing larger power supply filter capacitor values.Regards,Jim
Too much agreement kills a chat.  E. Cleaver

-----Original Message-----
From: Al Klase <ark at ar88.net>
To: Milsurplus at mailman.qth.net
Sent: Sat, Jul 3, 2021 10:42 am
Subject: [Milsurplus] Waking up Command Receivers

  Gang,
 
 We all have these things languishing in our collections.  Here's how to use one without building up a complete system.
 http://www.skywaves.ar88.net/homebrew/ARC-5_PS/ARC-5_PS.html
 Let me know if you have comments or corrections.
 
 73,
 Al
  -- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net ______________________________________________________________
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