EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: deafen on November 25, 2021, 07:40:59 pm

Title: Schematic for early HP 202a?
Post by: deafen on November 25, 2021, 07:40:59 pm

I just picked up an early HP 202a function generator (mid 1957, based on component dates). The only manual/schematic available online starts at serial number 5612, but mine is in the upper 3000s. The most obvious difference is that the manual shows 12 silicon diodes in the sine shaping circuit, whereas my unit uses six 6AL5 tubes. Unlike other vintage HP manuals, there's no list of changes from older revisions. While obviously the diode difference isn't a huge deal, it does make me wonder what other circuit changes there might have been.

I know it's a long shot, but does anyone have access to an older schematic or manual?