Hello, I Recently got a new-to-me Apple //c but upon powering it on it displays a garble of flashing characters. I've already re-seated the IOU, MMU, CPU and MON, as well as the Power Supply and Character Generator. I've attached pictures of the monitor as well as the components. Everything is in really good condition and I've confirmed that the external Power Supply and Monitor are working on another system. Looking for advice before proceding.
https://i.imgur.com/Vp2dc7a.jpg
https://i.imgur.com/eBjlTFi.jpg
I'm no expert - just found my apple iic and it still boots up, having not been used since 1988. Does the self-test work? It's meant to check a few items and report which is faulty; maybe it'll help for you?
https://apple2.fandom.com/wiki/Built-in_Diagnostics