Was sold as “defective, no picture”, but was actually working.
Known Issues
Minor damage to the case on the backside, probably by softening agent of power cable.
Restauration Works
Cleaned and whitened the case.
Fully disassembled and cleand the keyboard.
Recapped. Also changed 7805 and 7812 with DC/DC converters.
Removed the VIC cage, which was actually just a tin cover.
A cerco was damaged, probably it got stuck between the PCB and a screw. I replaced it with a new cerco.
Refreshed soldering of the DIN connectors.
Diagnostics reported that both CIAs were faulty. In an attempt to fix that, I ended up with removing both CIAs, the PLA and the CPU, and soldering in sockets, to insert known-good components. The issue remained though. It turned out that I made a soldering bridge while refreshing the solder on the DIN connectors. After I removed that bridge, the system was diagnosed OK even with the original chips.
