If you wan only 10 MHz, go for a Tek 564A with a 3A1 and 3B3. If you want 50 to 60 MHz, a Tek 453A or 465A. I would not mess with a 535 or 545 or any HP scope. Even 7000s are cheap now, and still very good instruments. I use 7854s. FWIW, -John