I had the need to match a batch of transistor pairs for a project, so I designed a circuit board based on a circuit by Ian Fritz.
Transistor matching test fixture
Hewlett Packard 3551A Transmission Test Set
Checking out a HP 3551A sold as “For parts or not working, will not power on”, that I actually purchased for parts.
My original intent on purchasing this unit was to salvage the knobs and connectors for repairing some of my other HP gear. I did manage to swap out four of the knobs before my curiosity got the better of me.
Hewlett Packard 10548A Diagnostic Service Kit
After spending many hours working on my Hewlett Packard 5300 series measuring systems, I decided to remake my own version of the HP 10548A diagnostic service kit.
