Tek 7904 scope

I suggest you try to locate a older tek catalog from the 1980s. They are excellent sources of information. As far as amplifier plug ins, you could use a 7A19 also as they go to 600 MHz. 7A29 DC to 1 GHz 7A19 DC to 600 MHz 7A24 DC to 400 MHz Dual Trace All these are 50 ohm input by my 1987 catalog. Time Bases are the 7B80 Triggering to 400 MHz Basic Delayed Time Base 7B85 Triggering to 400 MHz Delta Delaying Time Base 7B92A Triggering to 500 MHz Dual Time Base, Delayed and Delaying I think the 7B85 is the most common and the most sought after time base. Another fun thing about the Tektronix catalogs is their original 1987 asking prices 7904A Mainframe $10,115 (no plugins) 7A29 $3,325 7A19 $2,895 7A24 $2,655 7B80 $1,660 7B85 $1,940 This plug was in high demand on the used market 7B92A $3,745 7CT1N $1,785 7A26 $2,350 This plug was in high demand on the used market 7A18 $1,465 7B53A $1,860 This plug was in high demand on the used market When I was selling Tek used equipment 10-15 years ago I felt lucky to get 10% of those prices. I bet it is a lot cheaper now. Nice scopes. I regretted getting rid of my 7603. Paxton -- Paxton Hoag Astoria, OR USA