[Collins] Collins 30L-1 and Harbach SK-300 Soft-Key

[Greg Beat]

Here are the instructions (and schematic) for interfacing the Harbach
Electronics SK-300 Soft Switch for the Collins 30L-1 amplifier

http://www.harbachelectronics.com/pdffiles/sk-301.pdf

The circuit uses both a IRF 9610 (P-channel HEXFET) and a 4N33 optoisolator
Always good to see what is involved with installation, before the purchase.

Jeff Weinberg has replacement capacitors and a soft-switch for a variety of
amplifiers.

Greg
w9gb