This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
D1650 7A What part should I get? The transistor is part Q502 on the PCB of the Applecolor RGB monitor, manufactured in 1987. This is the only power transistor in the HV section, the only one which is on a heat sink. ...." D1650 is a 2SD1650 which crosses to an ECG2331. You should be able to pick one up at your local electronics shop. Try MCM Electronics, Dalbani, etc.. By: "John F. Reeves" and Sam Goldwasser ===========================