The pickups are fine, and I'm not overly concerned a out keeping things intact, I was really just wanting the vintage control panel and hoping to get it fixed.
Putting on my retired electronic engineer hat...The control panel is a couple of potentiometers and three switches. Those types of components often fail over time and it may only be repairable by replacement. It could alse be as simple as a cold or cracked solder joint. Any competent luthier who works on electric instruments and equipped with the proper schematic (they're online) should be able to figure it out.
Personally I'm not a fan of the Hofner control layout and I replaced one with a VVT setup and competely bypassed another so just the neck pickup is connected to the jack. That was on current Icon/Ignition Club Bass models and I wouildn't recommend it for a vintage instrument.