[Milsurplus] Need help with ART-13

[WA5CAB at cs.com]

Bob,

Pin 5 is ground (chassis) in the transmitter, or should be.  Check where 
pins 2 and 9 go both internally and externally.  They should only go to the 
meter switch inside the transmitter.  In the original installations they ran 
over to the dynamotor or AC supply.  Inside the dynamotor, they ran to the 
altitude switch which connected them to the meter shunt(s).  Inside the AC 
supply, 9 went to ground and 2 went to the junction of the meter shunt and the 
HV secondary center tap.  But I would ring out the wiring inside the 
transmitter before making any changes.  If U-7/U has nothing connected to 2 and 9, 
something has to have been done inside the transmitter or the meter would be 
dead in the P.A. Plate position of the meter switch.

In a message dated 3/8/2011 5:18:30 PM Central Standard Time, 
kn4hhptc at yahoo.com writes: 
> Meir, Jack, Robert, Ralph, Ray, and Mac,  thanks so much for all the 
> wealth of information.  My power supply is actually three separate supplies 
> mounted on a common chassis.  The 26v, 400v, and 1200v supplies are all solid 
> state.  There is a 12.5 ohm 10 watt shunt resistor on the centertap of the 
> power transformer supplying 1200VDC and is connected to pin 5 of the ART-13 
> power connector.  The center tap is floating, at least to the point where 
> the shunt resistor is connected to pin 5.
>  
> The only band I have tried to load up on is 80 meters.  I can watch my 
> wattmeter and adjust the tune and load controls and get a definite peak on 
> output power albeit only about 30 watts carrier.  I have listened to the 
> signal in my 51J4 and it is on frequency.
>  
> I will loook at the meter circuit.  The unit appears to have not been 
> modified anywhere I can physically observe.
>  
> Bob, KN4HH
> 
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480