[Milsurplus] DY-105 hookup

[W7QHO at aol.com]

In a message dated 10/9/06 3:19:46 PM, windy10605 at juno.com writes:


> Don't have a schematic, but is the vibrator in the DY-105 just for the Rx
> power (and maybe the Tx osc) and the dynamotor is for the Tx and only
> comes on when the mic is keyed ?
> 
> 
Kees,

When connected up to the GRC-9 or BC1306 radios, the DY-105 vibrator supply 
comes on when the radio's mode switch is set to STANDBY.   The dynamotor comes 
on when the mode switch is set to SEND and RUNS CONTINUOUSLY.   The 
transmitters will then be activated (keyed) when the mic PTT switch or the telegraph key 
is depressed.

The GRC-9 and BC-1306 will run on the HV (500 vdc) alone.   The +105 volts 
(LV) required for the receiver (and LV circuits in the transmitter sections) 
will be derived from the HV supply via dropping resistors and a VR-105 tube in 
the radios.  The sets run this way when connected to the PE-106 MG set.   In the 
DY-88 and 105 power supplies the vibrator supply was included to allow the 
receivers to operate in STANDBY with the dynamotor turned off, thus saving 
power.   Interestingly, the LV vibrator supply in the DY-88 is disconnected from 
the radios when the dynamotor is running but this is NOT done in the DY-105 or 
the older "all vibrator" supply, the PE-237.

There's no apparent reason why the 105 or 88 dynamotors couldn't be switched 
on PTT if used in some other application.   Might be possible to modify a 
GRC-9 or BC-1306 to operate this way too but I haven't looked into the matter.

Dennis D. W7QHO
Glendale, CA