eHam Forums => Amplifiers => Topic started by: AF8JC on December 03, 2017, 05:43:14 PM

Title: ALC adjustment on Icom IC-2KL
Post by: AF8JC on December 03, 2017, 05:43:14 PM
I have managed to get my amplifier working and have good output. I have tried to follow the instructions on page 10 of the opeator's manual for "Adjustment of ALC Level" without success. In the third paragraph under the topic, it says "Turn ON the LINEAR AMP switch, and set the exciter in the transmit mode and transmit carrier (on CW or RTTY) with full power condition."  Note those last three words: full power condition.

On page 1 of the manual, under SPECIFICATIONS, it says  "Driving Power: 50W ~ 80W".  So it seems like the amp is looking for 50 to 80 watts of drive and I am using an IC-706 with 100 watts.

Any attempt to drive the amp in CW mode power greater than about 30 watts results in the PROTECTOR circuit kicking in. I find I can drive the amp with 20 to 25 watts and get 500 watts out easily, but trying to set the ALC adjustment with the meter in the PRO position is very frustrating. The control seems incredibly sensitive/touchy. I sprayed some electrical cleaner through an opening in the back of the control and rotated the shaft back and forth. I thought it might be like a "jumpy" or "scratchy" volume control. It still seems way too touchy. In the end, I got the ALC control close, and then tweaked the drive power of the IC-706 to fine tune the needle position.

Other users on the Yahoo Group for the IC-2KL have commented about the "sensitive" ALC adjustment and most seem to be getting full output with 20 to 30 watts of drive. Should I assume the manual is incorrect when it states to use full power from the driver/exciter? I'm just trying to figure out if I need to replace the ALC pot or if there is something wrong with the ALC circuit.


Jim Caudill AF8JC