[MRCG] homebrew GRC-9 power supply questions

[Dennis DuVall]

On May 14, 2013, at 8:50 AM, Jason W6IEE wrote:

> I posted this to the ANGRY-9 list, but being as there's very little  
> traffic
> over there, I want to ask here also.
>
> I have a Lewyt AN/GRC-9 but no power supply!
>
> Having quite a bit of vintage junk, I'm going to try to build a power
> supply as can be seen here:
>
> www.vmarsmanuals.**co.uk/newsletter**_articles/**angrynine_**2.pdf
>
> First issue, the plug I have has no pin #58. As I understand it,  
> this is my
> receiver B+ on receive. Should I just jumper 57 and 58 on the radio?

Jason,

You can use pin 57 only but then the receiver will only operate when  
the OFF,
SEND, STANDBY switch is in the SEND position.  The radio will not
actually transmit until keyed of course.

>
> Next, I'm having a bit of difficulty understanding the purpose of the
> OC3/VR-105 gas-tube regulator for the 105V line. As I understand it,  
> that
> tube won't even "strike" until 135V goes through it. Is the purpose  
> of this
> tube only in the event an excessive voltage is put on this line?

The 0C3 is what holds the "105V line" at 105 volts.  With the power  
supply
circuit shown in the reference (above) the output voltage from the "105V
supply" will actually be around 150 volts until connected to the GRC-9  
and
it's internal 0C3. Note the inclusion of the series resistor in the  
circuit.

You can accomplish the same thing with a dropping resistor off the 550V
supply.  This is done with the PE-162 MG set used with the GRC-9. The
PE-162 uses a 7.5K and a 2.5K resistor (both 20W) in series for a  
total of 10K.


>
> Since I don't have a 105-0-105V transformer, I'm wondering if I  
> could feed
> that line with ~135V, instead of 105, with the appropriate resistor?  
> (back
> to back wall wart transformers
> would likely be more in this voltage range) My other option is a big  
> bag of
> 33V zener diodes, I could make a 99V zener regulator. This should be  
> ok,
> (right??) as I've run the receiver in the past with 90V worth of 9V
> batteries. (and yes, my bias battery is dead, coming up with a  
> strategy to
> replace with button cells)

See above.

>
> Lastly, my final B+ supply is going to come out to be around ~550V  
> instead
> of 500. Will this be OK? Sure, the 2E22 is rated at 600V max, but  
> will the
> screen voltage end up in an acceptable value?

550V OK,  the manual (TM 11-263) lists 580V @100ms for the transmitter.

Do you have a manual?

Dennis D.  W7QHO
Glendale, CA


>
> I am aware of the scarcity and short life of the 2E22, I have a few  
> of what
> I believe are NOS spares.
>
> Of course, I'd much rather obtain a DY-88, but I haven't won the  
> lottery
> yet. ;)
>
> Thanks,
> Jason W6IEE
>
> -- 
> w6iee.blogspot.com
> AMI, Cactus Intertie, CVRC, GQRP, QRP ARCI, SBMS, SKCC.
> http://en.wikipedia.org/wiki/Junk_box
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