Apple IIc from Scryption collection

I recently bought some of the ‘leftovers’ from the Scryption Museum which unfortunately had to close due to lack of funding. Here’s one of the systems I bought from them, an Apple IIc with matching monitor and power brick. It powers up, displaying “Apple //c” and “Check Disk Drive.” messages. Hitting Ctrl-Reset gives me a working BASIC prompt. print peek(64447) returns 255.

Actually, I have two IIc’s with matching monitors (green, composite). Both work fine as far as I can see, but both won’t work properly with the external Disk IIc (could be a faulty Disk IIc). Internal drives are fine, managed to receive and write disk images with ADT Pro and a cable from!
Apple IIc s/n are C5 05WK XX and C5 29S3 XX. Disk IIc serial is 139997 (model A2M4050Z).