Recent content by jdreesen

I decided against, as it would not really be more useful then the emulator. The time redeemed that way was spend on an even more useless endeavour : ...but still quite some way to go...

For the AMD2901 based Lilith I have the sourcecode, and a modern assembler, for the complete microcode.

I should have V4.3 and V4.4

You might want to check this : https://forum.vcfed.org/index.php?threads/tektronix-4052-54-diagnostic-rom-pack-remade.63974/post-1315932 It describes replacement for these ROM-s Alas I also do not have the early V4 version

Not to my knowledge...

You could of course just use a SN76489 sound chip. it is basically just a 8 bit port and could easily be integrated into a MFM. Alas I have no experience in working with sound effect chips...

I feel a project coming on.......

The machine should come up to a prompt, even without disks or floppy. Did you using the MB in standalone mode ? WRT to harddisk : any MFM disk, or David Gesswein's MFM emulator should work. Somewhere in my floppy-images is a tool to initialize a harddisk, I did so on a 160MB disk. Also : your...

Appended is a disassembly of the BIOS ROM... And yes, time to connect the logic analyzer...

I use an Expro-60 or Expro-80, also sold as ALL-03 or ALL-07. Very versatile and properly documented, I wrote some code to read devices under Linux. WRT to that WD1001 : there is also the option to replace the WD1001 with a WD1002-05 or WD1002-HDO. These are hard-, soft- and format-wise...

Make it easy on yourself and just copy the 1K 8 times into the WS57C49C. Then A10,A11 and A12 become don't cares... Are you sure the PROMS are defective ? Compare the contents with the one on bitsavers.

Look for the WS57C49C : a 70ns EEPROM with 82S191 pinout. 8Kbyte iso 1Kbyte, otherwise a drop-in replacement.

So the 2.6V is OK. Then the only other thing I can suggest is to pull both SRAM. There the parameters are stored, forcing the system to use defaults.

You should be OK with just RX/TX/GND. 13.3V and -11.6V would not worry me, I would have used the original supply after removing the RIFA's. The PCB will boot without a floppydrive attached. I would still remove the battery, forcing default for all parameters. Or remove RF14 /33ohm, that also...

I did not...