Chirping is hard to diagnose exactly, but it and the common "flupping" sound are both a sign that the power supply is unable to get going, and is restarting at regular intervals.
Larry Pina wrote two books that will be helpful: Macintosh Repair & Upgrade Secrets, a repair manual for the Plus and earlier (and a little bit of the SE and Lisa), and Dead Mac Scrolls, a symptom and diagnosis manual, the "DSM" of early Macs....
I've attached them here. Possible problems could be: diodes, transistors, rectifiers, resistors... The list goes on, but Larry is very thorough, and has many checks for ruling various things out.