HP 3312A Repair (Bad Switch Contacts)

[Jackson]

Hello all,

I'm currently working through a back log of teardowns/repairs I'm working on (and have finished). This one is a successful repair from a couple months ago, an instrument I obtained over the winter (along with several others) from a Craigslist deal. The function generator worked well except for the range switches (see video below). It seemed to be stuck on a certain range. Looking at the schematic (attached) and seeing the way the range switches were all laddered together, I went about testing them all when pressed/unpressed for continuity. Sure enough, the 1 MHz and 100 kHz range switches both showed spotty continuity. A bit of Deoxit and some actuation later and the thing was as good as new! 

https://youtu.be/JVX2LxFuFkQ

[Jackson]

And for followup, here are some general images of the insides that I took when I had it apart. Nice and tidy inside. Unseen in the top of the last picture is the bottom row of BNC connectors and dials, which are obscured by the metal frame.