I was going through a book that has some vintage circuit schematics and came across a nifty one in the CRT section. This circuit will expand a single or dual channel scope to four channels.
The circuit provides a four channel display with a HA-2405 four channel programmable Opamp. It provides a unity gain per channel, the bandwidth of DC to 5MHz. The maximum input voltage of plus or minus 10 Volts and a slew rate of 15 Volts per micro second.
The top right side chip is a 7473 Flip-Flop. Also the voltage divider for the “From Scope Gate Out” is a 5K and a 1K. The 1K is going to ground.
I haven’t tried this schematic but let me know if you are willing to try.