S95Sedan wrote on 2023-10-23, 21:01:
Heres what the debug comes up with.
as @keropi already said that is not MQ ROM running at the moment - it returns the Roland Revision numbers, i.e. "1.5A" - as I already mentioned in this thread, end of the post here:
Re: MDR-401 cards - are they really existed or are they an elaborate hoax?
such scenario returning the Roland number is highly suspicious and I doubt anyone in 1991 would have done it and even dare to do it. I mean all other MPU-401 card use their own Revision numbers - I guess for 2 reasons - avoid legal actions from Roland side, plus they are not cloning any Roland card, but just re-implementing MPU-401 intelligent MIDI protocol (in that sense no any such card made in the past was Roland card hardware clone). So, I am back to SoftMPU/HardMPU recent port to Zilog Z8 hypothesis I said many times, because "1.5A" is what SoftMPU is using.
[EDIT]
keropi wrote on 2023-10-23, 21:03:
no need to desolder to find if it is or not
yes, but you need to desolder it if you want to try the card with MQ ROM, i.e. see if the board layout is fully compatible with MQ or not. in fact looking at the card, even if it's not fully MQ compatible it can be made with some rework - after all both cards are Zilog Z8-based and use almost the same layout and chips.