[ARC5] Ideas on Japanese circuit ?

[Christopher Bowne]

Perhaps to allow the receiver to be operated from batteries during receive/standby and or to allow the dynamotor to run only when transmitting, to conserve battery consumption.  GRC-9 can be operated in this manner.  GRC-9 dynamotor only supplies transmitter.  Receiver B plus from vibrator in the DY-88 power unit, or external Bbattery, also can supply rx from external A battery.

Sent from my iPhone

> On Jul 8, 2023, at 16:59, Hubert Miller <Kargo_cult at msn.com> wrote:
> 
> I have been trying to figure out the schematic and connector pinouts for a Japanse I J A Type 99-1 
> radio set. Here's something that puzzles me. Maybe you have an idea why done this way?
> 
> Rec dynamotor unit has 2 separate output fields. One has -B and +B to receiver. Other has one side
> grounded, the + side goes like this:
> 
> LV dynamotor =>  connector => cable => receiver connector #4 => ? drops off LV for tube filaments ? and pilot
> lamp and jumpers to receiver connector #6 => cable to transmitter connector #6 => keying relay and
> microphone current. 
> I cannot see how the tube filaments are supplied as the filament connections are not shown and the Japanese
> text characters are too small to see clearly.  
> WHY would the keying relay and mic be powered off the dynamotor and not the 6 volts main supply? 
> Maybe this is so you could have the input power polarity either neg or pos ground? The dynamotor primary is
> NOT connected to ground, both leads floating, so it could be powered either way. 
> What think?
> -Hue Miller 
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