[Milsurplus] DY-105/GRC-9X Relay K3

[W7QHO at aol.com]

Bill,

The first thing I would suggest is removing the jumper you put in to keep the 
2E22 filament continuously lit, fire up the '9 and the '105 and key the set a 
couple dozen times.   The way you've been running the rig K3 never gets 
energized and so the self cleaning action that occurs when relay contacts make and 
break current never takes place.   Contrary to your statement (see below) the 
2E22 filament draws maximum current when cold, not when it heats up.   Thus, 
the voltage across the coil of K3 and at pin 20 on J2 would be at a minimum on 
initial power-on and would never rise high enough during normal operation to 
energize the relay. 

The book (TM 11-263) calls for replacement of the relay under the conditions 
you are experiencing.   Have no idea where one might find a spare, though, so 
if the above doesn't work, you would have nothing to loose by carefully 
cutting the case open and mechanically cleaning up the contacts.

Good luck.

Dennis D. W7QHO
Glendale, CA

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Original message dated 9/2/08 3:34:42 PM, 
> 
> I appear to be having problems with K3 in my DY-105. This relay is used to 
> protect the 2E22 filaments from an over voltage by creating a voltage divider 
> instead of using both ballast tubes. It appears that the “transmit” 
> (de-energized) contacts are not in too good a shape. When the rig is turned on, the 
> 2e22 does not get full voltage. A quick “rap” on the relay and all is well 
> for that session. Next time the rig is turned on, I have the same problem. I 
> suspect that when the initial 24 volts is supplied to the DY-105 the relay 
> throws for a second until the filament in the 2E22 heats up and draws current to 
> pull the voltage back down. (The 2E22 filament is wired to come on with the 
> rig, not just in transmit.) The “rap” on the relay seems to make the contacts 
> conduct properly and connect both ballast tubes. The relay is quite sealed 
> or I would open it up and try to fix it.
>    So, does anyone know where to get a new K3? If not, at what voltage 
> should this relay throw so another one could be substituted? Any one out there 
> have any other suggestions? I have thought of wiring around the relay, but don’t 
> want to take a chance on harming the tube.
> 









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