Power Amplifier Dressler D200 (144MHz)

Mechanical modifications

I have added a robust metallic handle on the right side and tiny rubber feet on the opposite one. The handle is mounted on the bottom part of the box, close to the heaviest parts of the amplifier - both transfomers:

Tuning was sometimes very tough due to slight misaligment of the shafts.
I removed the rigid joint between the tuning knob and the shaft with the tuning plate and replaced it with home-made rag joint. Now the knob rotates very smoothly:

Electrical modifications

The DIL integrated circuit (stabilizer) for the antenna pre-amplifier seemed never been installed on the PCB. Instead, there was 7812 stabilizer soldered on the top of the PCB.
To make it more robust I replaced it with 78S12 (up to 2A) and mounted it directly on chassis for an ideal cooling:

I made a map of some parts on the PCB (relating to the schematics in the original documentation):

And this is the detail how the tube (4CX250R) is mounted in the PA (no mods):

 

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