There's something about having both the Drake and Heathkits together. This is my Drake "B" twins and the SB-104 station.
If your old Drake AC4 (AC3) needs to have some new life, you've found the right place.
Drake L4/L4 amplifier power supply upgrade
Replace all those old capacitors with 105 deg caps and all new diodes. This design used equalization resistors across the 3 amp 1000 V diodes.
Click her for more info!
This small pcb fits inside the Drake R4B and replaces the original calibrator board. You have your choice of either 100, 50, or 25 KHz markers. Best of all, you can have those markers pulse so you can find it on a busy band.
Drake L7 Hard Key Interface
This is very much like the hard key for the SB-200. This is custom made for the Drake L7.