From several dozens of oscilloscopes I have repaired successfully, that 2236 has been the champion of the nasty ones. Its power supply is so convoluted that I wanted to puke. Tektronix showed with that model family how crappy they can design one with the purpose of saving 5 cents. I wanted one that model; after seeing its guts decided to get a plain Hitachi.
Several electrolytic capacitors go leaky, shorted, open at the power supply... Remember a small one at the very edge of the PCB.
If you have to ask if there is dangerous voltages when unplugged, better abstain to get into it.