EB5AGV's HP-8640B REPAIR (II)

The very best on analog signal generators

HP-8640B

This repair started as a consequence of another test gear being checked (a Tektronix DC-510 counter). I fired up my second 8640B (which had been troublefree since I got it some years ago)... and it was not working fine!. It showed wrong frequency readings at all ranges. Immediately I knew what had happened: the dreaded rotary contacts were falling from their supports!


Repair works

I opened the unit and got out the RANGE and FM DEVIATION ASSEMBLY (as I did with my first HP-8640B some years back). Once dismantled, yes, one of the contacts was almost loose:

HP-8640B

This is a general view of the switch assembly parts:

HP-8640B

And then some close views of the parts:

HP-8640B

HP-8640B

OK so, what to do now?. In order to get the contacts back to its place and stay there some time, I used a bi-component epoxy glue. Here you have detailed views of the contacts back in place with epoxy:

HP-8640B

HP-8640B

Next day, I put back the 'kit' in its original assembled form:

HP-8640B

HP-8640B

HP-8640B

And got it back to its place in the HP8640B. Once the unit was checked, I got it back to the shelf:

HP-8640B

Success!!!


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