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Old 16th Jan 2020, 11:20 pm   #331
JohnBHanson
Heptode
 
Join Date: Aug 2009
Location: Worthing, Sussex, UK.
Posts: 662
Default Re: Gemini 80-Bus System

The mystery chip for IC14 looks to be an 74LS20 with pin 1 connected to +VCC. I cannot tell from the photo you sent me but is pin 1 bent under and connected to pin 14?

A few other pins look a bit strange from the photo...

From the photo the soldering down the lhs (eg pin1...pin5 or so) looks a bit odd - be nice to confirm that my assumption is correct.

PS- when you get the xbeaver emulator running with a gm849m_scsi card can you double check the scsi.bas program - should be the same as the emulator version now.

Latest emulator version boots MFB system directly - Simon can boot from the hard disk if there is not a floppy inserted which is hard to do on the emulator as it stands.

The analyse program almost works - just identifies as Single not Double Density as my emulator ignores the single/double density in the floppy disk selection. Also track read does not read any data.

However as MFB boots the data transfer utilities should work - however the floppy geometry in the config file will need to match.
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