After 5 years I finally decided to bring my MSX back to life. But with all the external hardware (the slotexpander, scartcables + selector for GFX9000, rs232c + external modem, novaxis scsi + harddrive and zipdrive) it barely fits on my desk. So I decided to build my NMS8255 into a miditower to save space.
NB. Before I built the whole lot into my miditower, everything worked fine except for the fact that the gfx9000 and de opl4 couldn't both be entered in de gouda slotexpander due to power problems. The setup worked with the gfx9000 in slot 1 and the opl4 in the slotexpander thouigh.
After I built the whole lot in an miditower a little problem arose which has been haunting me for two weeks now.
The problem is that everything works except for the Novaxis. It can only find the scsi harddisk but won't boot from it. Instead it exits to BASIC. Drive A: is not readable from DOS 2.xx. And physical drive A is mapped to drive B. Also the novaxis cannot detect the zipdrive. I can not enter the setup menu. It says wait or something, and then the computer hangs.
It does not matter if I use cartridge slot 1 or 2 directly or the slots in the slot expander. Other cartridges like Kingsvalley 2 or my FM-Pak work fine.In fact the whole MSX performs fine unil I attach the Novaxis.
The msx-mainboard is now connected to a 150Watt PC-AT powersupply which should be sufficient. I checked all the voltages +/-12V and +5V on the AT powersupply and they seem to bee correct. This is also the case with slot 1+2 and the Gouda slotexpander even with cartridges in them. Zip-drive, diskdrive A&B and the SCSI hd now get their power directly from the AT powersupply.
My first thoughts were that maybe the Novaxis SCSI interface had a defect or I had a bad SCSI chain, but when I put a dos 2.20 cart and the Novaxis in the slotecpander, and connect the slotexpander to my NMS8235 with doublesided diskdrive, using the SCSI chain in the miditower (zip + hd) the Novaxis detects both my HD and zipdrive and boots from it. Then everything seems to work ok. I can even enter the setup menu. So this rules out a faulty SCSI chain or bad termination.
I even replaced the MSX main board in the miditower with another. But still I have the same problem.
Specs board 1:
Philips MSX2 NMS8255 board with built in dos2.20, fast diskrom 7 mhz and 512kB RAM
Specs board 2:
Philips MSX2 NMS8255 board with built in dos2.20, fast diskrom 7 mhz and 256kB RAM
I'm very puzzled.
Does anybody have any ideas on how to get the novaxis working? what are the tolerances of the novaxis?
- Could it be a grounding problem?
- Is it advisable to supply the slotexpander it's own +/-12V and 5V from the AT power supply instead of getting it from the MSX main board via slot 1 or 2?
Any help/hints would be greatly apprciated.
Gerald
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