This is a single 25 Channel Driver Unit.
Its front panel indicates what quadrant and what standoffs it drives.
The rear panel shows its input from the Controller Unit, and its output to the Peltier devices on the dish.  There is also its cable from 2 (100A ea.) power supplies.
The Driver Unit houses 25 power amplifiers mounted on a large heatsink plate.  This heatsink plate is dual air and liquid cooled because of the number of amplifiers I mounted on it, plus its operation at altitude.
(Early pics of amplifier boards and heatsink plate.  They are a bit different now.)
~Melanie Leong~