I read in some forum post that the 63B09E is a possible substitute for the 68B09E e.g. for use in WPC/WPC95 CPU boards (I could not find the post anymore though)
Some infos about the difference to the 68B09 are here: https://en.wikipedia.org/wiki/Hitachi_6309
I ordered 1pcs HD63B09EP (Hitachi brand) from Aliexpress some time ago-got lucky as it was no fake and it was working when installed in my T2 and also in my FT WPC89 CPU without issues
As I reorderd 4pcs from Ali again I was testing around and found out something strange:
All the 4new HD63B09EP (Hitachi) work great in my T2 CPU, also work in my FT (nonDCS) soundboard but NONE of the 4new work in my FT CPU
Not working means it usually boots but behaves strange as the message "all bookkeeping data cleared" appears; also entering e.g. the menu is not possible and often the CPU just reboots...
Also tested with a third original B/W CPU board which also reboots/has the same issues as described above
what really puzzles me is the case that:
1pcs OLD HD63B09EP works on both CPUs (T2+FT) but
4pcsNEW HD63B09EP work NOT on the FT CPU but are fine on T2 CPU and FT soundboard
Both the T2 and FT CPU are original B/W WPC89 CPU boards ((A12742-xxx) with same type of NVRam installed and "should" be the same except for the gameROM and different country settings (I´m not aware of the revisons-if there are any- of the boards-maybe some components are different/got substituted)
I think one can not blame the chips in that case as the 4New ones look like NOS to me-they didn´t even have marks from being inserted in a socket when I got them-pics attached-scratches on the bottom made by me
Someone has encountered something similar or maybe have any hints where I could look for?
e.g. are the processors operated at the edge of their specs what could explain that they work on one board but not on the other ones due to tolerances of installed components??