24-10-2016, 02:34 AM
Well done on the repair - I had a 7904 for years - lovely scope - was the first scope I had as an undergraduate engineer at STL so had nostalgia value.
Sold it about 10 years ago as it was just too big and clunky - now use a 2465A... Most of the equipment in the photo below has now moved on and been replaced by more modern stuff...
EDIT: The little board on the test bench being menaced by the equipment surrounding it is a Jim Williams ultra-low-distortion oscillator ( 0.0003% or 3ppm) as described in Linear Technology Application Note 43f, figure 48. The big amp on the right is a rebuilt Perreaux 2150B (200W min RMS per channel into 8Ω at 0.009% THD)- a glorious class AB amp that was our main HiFi power amp for a few years - when switched on, the top-plate used to flex and the lights dimmed slightly. Next to it is a 150W non-inductive dummy load for soak testing the amp without going deaf
Sold it about 10 years ago as it was just too big and clunky - now use a 2465A... Most of the equipment in the photo below has now moved on and been replaced by more modern stuff...
EDIT: The little board on the test bench being menaced by the equipment surrounding it is a Jim Williams ultra-low-distortion oscillator ( 0.0003% or 3ppm) as described in Linear Technology Application Note 43f, figure 48. The big amp on the right is a rebuilt Perreaux 2150B (200W min RMS per channel into 8Ω at 0.009% THD)- a glorious class AB amp that was our main HiFi power amp for a few years - when switched on, the top-plate used to flex and the lights dimmed slightly. Next to it is a 150W non-inductive dummy load for soak testing the amp without going deaf
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