[Milsurplus] [MMRCG] Navy MAK and the HY1269

[Nick England]

FWIW, My guess is 220 VDC for the receiver and 550 volts for the xmtr

The CCI-20193 vibrator supply for the MAK says
CCI-20193 VIBRATOR POWER ASSEMBLY:
INPUT 12 VDC 27.5 AMPS
OUTPUT 220 V DC.
OPERATES WITH A -21984 DYNAMOTOR

The CCI-21984 dynamotor for the MAK says
CCI-21984 DYNAMOTOR
INPUT: 11.5 V DC AT 15.5 AMPS.
OUTPUT: 550 V DC AT 200MA, APPROX.
FULL  OUTPUT 190MA.
FOR OPERATION WITH -20193 VIBRATOR POWER ASSEMBLY.

Nick England K4NYW
www.navy-radio.com


On Fri, May 24, 2019 at 10:18 AM Ray Fantini <RAFANTINI at salisbury.edu>
wrote:
>
> So a WW2 Navy model MAK 25 watt HF AM transceiver followed me home from
Dayton. Been looking into using it for a portable 3.885 transceiver at
various field nets and the like with others who are using things like
BC-611, pogo Stick and other WW2 AM transceivers. Think it’s a good choice
being it relatively small and low power and built to work with a short
vertical antenna. In the process of building external Dc to DC converter
power supply that will probably attach to the back of the radio out of
sight and run everything from twelve volt DC source.
>
> Lot of this is easy, being the filament strings are already configured
for twelve volt operation, all the tubes in the receiver are twelve volt
like 12SK7, 12A6 and the like and figure the receiver will work just fine
at around 180 to 190 volts DC for the plates but the real question is
what’s going on in the transmitter.
>
> The transmitter is a four channel crystal control using a 12A6 as the
oscillator that drives a HY1269 PA tube, that tube is plate modulated y two
more HY1269 tubes in parallel.
>
> This is my first exposure to the HY1269 tube and it appears to me to be a
quick heating power pentode rated at 30 watts, 750 volts max DC plate at a
max current of 120 MA.
>
> Just playing around with lighting up the filament string at eight or ten
volts the filament appears to be real bright. Looking at the specs I can
find it shows the tube can be used at six or twelve volts with a center
taped filament. The filament, cathode and suppressor grid are all tied
together internally in the tube. All three tubes have their suppressor
filament center taps tied together decoupled to ground thru a capacitor but
also a variable resistor is involved with that circuit. From what I can
determine the whole mess was feed from the common DC input with a separate
switch that powered the transmitter section by itself that brought in a
relay to power up the filament string and the dynamotor for the high DC
voltage was activated by the PTT line.
>
> First question: How bright are the HY1269 tubes supposed to burn? They
light up real bright, almost like light bulb filaments at ten volts and
being that it’s hardly the most common tube don’t want to risk burning open
any of them.
>
> Second question: what should I plan for a plate voltage for the
transmitter? I figure it’s going to be around 400 DC or should I be higher?
Maybe something like 500 or 650 DC being the tube is rated good to 750?
>
> Attached is the only schematic I have been able to come up with and it’s
not very good. The key thing here is to build up an external power supply
but not one that puts the tubes in danger, will also be looking at things
like the voltage ratings of all the bypass capacitors and the plate
coupling capacitor and thinking maybe the key maybe too go with half the
rated voltages?
>

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-- 
Nick England K4NYW
www.navy-radio.com
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