HP 8565A: Sweep time selector

As I already mentioned, the highest priority fix is the input RF attenuator. To get access to this, the control panel must be taken out since the connector is placed at a slightly inconvenient place – the bottom of the motherboard. Unfortunately, right beneath this is the aluminum carrier plate that contains all the RF circuits consisting of semi-rigid coax and clunky metal-jacketed modules. I first unmounted the top, bottom and right side panels, which was an easy job:

  • Loosen the single screws at the back of top and bottom covers and pull them off towards the back.
  • Remove the two screws holding the carrying handle and pull off the side panel along with it.
  • Also remove the top and bottom plastic inlays from the front aluminum frame, these cover up the panel screws.
  • Remove all visible screws from the top of the frame that seem to belong to the right panel (should be 3) and also from the bottom (should be 2). Take care not to remove the 2 rightmost screws on the bottom, these hold the front connectors and are best left in.

Now pull the control panel right out.

IMG_1011_web

Fig. 1: Control panel removed from case.

If it sticks, the points to watch out for are the N-type RF connector and the PCB edge of the sweep time selector. Gentle pulling while wiggling the panel up and down some will bring it out. Remove all connectors from the backside. Don’t worry, the plugs can’t be interchanged. Set the panel on a flat surface, front side down (Fig. 1). [Read More]