08 January 2014

Gould 4072 PSU - removal steps

In the end I deciced to have a look at the Gould 4072 DSO Power Supply Unit: since the scope was already going to be trashed, I cannot do much more damage. So, how to access the PSU?

First of all: you will remove a lot of different screws, be methodic and classify them. I was not.
Second: you will probably meet a lot of dust.

Needlessto say, remove the AC cable. Remove the top cover (5 screws). Remove the bottom cover (7 screws).

The PSU has the following connections to the PCB:
  • to the nearby fan (access from above)
  • to the CRT circuitry (access from above)
  • the metallic ribbon to the front panel on/off button (access from above, remove it from the button, don't remove the button)
  • to the bottom side with four fast-on's (access from below)
  • to the bottom side with a flat ribbon (next to fast-on's)
  • one ground wire to the chassis (I cut it and will solder back)
Ribbon cable to the CRT
and the ON/OFF strip.
Take a picture of everything before removing it.

The PSU slides towards the top of the DSO, so prepare all the cables accordingly.

Remove all screws on the back panel except for those holding the fan. Your aim is to be able to separate the back panel top side far enough to let the PSU slide out (up). The whole operation can be comfortably accomplished with at least three hands :) Pay attention not to damage the metallic on/off strip.

Once the PSU box is free there are still 4 screws that keep the lid in place.

Fast-on's, ribbon and ground
wires on the bottom side.

Edit 2014-02-11: I do not own anymore the Gould 4072.