I'm doing some research on my own broken BG8002 so I found a thing or two about it.
Do not throw away the microprocessor chip yet! There is no replacement anymore. First make VERY sure the chip is broken. It could still be something else, e.g.:
- electrolytic capacitor anywhere else in the machine. Replace them all.
- broken solders, especially on the connectors and inside the microprocessor can. Resolder these and inspect thoroughly!
- broken trace, especially around connectors and inside the microprocessor can
- bad connection of the microprocessor chip IC socket. Replace it with a quality new one
- Reading sonavors big BG8002 post I'm thinking the 4.7nF ceramic caps inside the microprocessor can are going bad in many of the BG8002's. Desolder and check/replace them.
Repairs on this machine are very work intensive and maybe best left to a serious expert, e.g. Dillen or Sonavor. 'microprocessor is bad' is an easy to make conclusion for the average tech guy if they are inexperienced with the BG8002.