[AMRadio] Question for GK500 owners

[w5jo at brightok.net]

Do you have an MFJ 259B?  If so feed it into the antenna port, be sure the 
antenna relay is closed and put a 2500 to 3 K (preferably 2.8K) carbon 
resistor from the plate of the 4-250 to ground.    Set the frequency of the 
259 to an 80 meter frequency of interest then try tuning the final to see if 
you can match to around 50 ohms on the 259.  Of course, be sure the final 
band switch is set to 80 meters.

If you can tune the meter to see a ~50 ohms on the 259 then the final 
compartment is ok.  If not you have problems in it.    It almost sounds as 
if you are tuning a harmonic rather than the fundamental.  Have you tried 
replacing the final tube?  I hope you are trying to load into a dummy load, 
if not, the antenna is wrong, maybe.  Are all connections in the final 
compartment good, nothing has come loose?

I don't need to remind you to do this with all voltages turned off, but will 
anyway.

Jim
W5JO


-----Original Message----- 


I'm having trouble with my Globe King 500B, which previously functioned
properly.

Now, the initial tune up process is per the manual, and with the exciter
set to VFO Operate and closing the Transmit switch, the plate current dips
to around 160 mA adjusting the Final Plate Tuning cap. But advancing the
Ant. Loading cap I'm unable to increase plate current more than a few
milliamps, and regardless how much Ant. Loading is advance the current is
well under 200 mA and RF output is a little over 100 watts. This occurs on
80 and 40 meters. On 20 meters, when I close the Transmit switch, I can dip
plate current to 200 mA but it cannot be increased above that. 73,
Brad K4RT