falter
Veteran Member
So as I mentioned in my MC1488 post I am trying to flash up this Insight Enterprises Z80 board I got a while back. There is not a lot of info about it - the company seems to have lasted less than a year. It is basically a Big Board type deal, but it was offered fully assembled rather than as a kit as far as I can tell, and had graphics, more RAM, etc. I am doing a video as I do this, mostly for my own benefit, although it will also appear on Youtube eventually. I'm finding as my collection gets bigger the space between use of machines gets longer and longer and I often forget what I did to get something unusual like this running.
Pics of the board are here, along with dumps of the ROM.
Google only turns up a few references, mostly ads and a mention in Microconucopia.
Since there is zero documentation, my strategy is as follows:
1) Backup the EPROM
2) Trace the four pin power connector
3) Trace out the video, in hopes of finding a composite out I can tap into.
4) Hook up power and monitor and see if we get anything.
5) Figure out how to connect a parallel ascii keyboard, which the ad says this machine can handle.
I've already done 1), and 2) seems pretty straightforward. I knew where +5V was on most 74xx devices, so I used my DMM to trace that to pin 1 of the connector. Ground you can see connected to the ground pin of those chips and to the ground plane that runs around the board, so that's pin 2. I made a guess that there wouldn't be -5V on a board this late, so the other two voltages had to be +12V and -12V, since we have serial I/O. I used my DMM and confirmed VEE on that MC1488 links to pin 3, and VCC to pin 4 of the power connector. So I think I've got that solved.
For the video, I'm using my experience from fixing up my Dynalogic Hyperion, which seems to use a similar design for video. There is a CRT8002 attributes controller, and if it's like the Hyperion when it's in text mode all the text has to pass through it and out the VID pin (pin 1). So I've been tracing that out and it does seem to land over where the video componentry is.. it runs through a 7486, 7406, some resistors, etc and then takes off halfway across the board. Haven't followed it the rest of the way yet. I strongly suspect J9 is where video comes out, given its proximity to the CRT controller, static video RAM and transistor. I don't see anything about colour, so I presume it's probably like the Ferguson - it might have some ground pins, composite out, and then horizontal and vertical sync for a monochrome TTL monitor. Figuring out which is which might be tricky for me but i'm looking at other similar designs for clues.
The keyboard is the tough one. I don't think the header for it is J1, J2 or J4.. those are 34 pin and I think are for floppy. I think J10, J11, J12 and J13 are serial related. J6 or J8 is probably SASI. J7 may be the fourth floppy controller. So I'm kind of dialed in on J5. If I'm right, the trick will be figuring out where the strobe and ASCII bit pins are.
I think my odds of getting this thing to even flash up are 50/50. Comparing the ad photo to this board, I can see the ICs are not in the same positions. I'm not sure if the ad photo is of a prototype that later got changed into what I have, or the other way around. I suspect the other way around because this board has a handwritten 'IE-118' serial number and a bunch of jumper wires. If it's a prototype, it may simply not work.
Powering it up successfully may be the best outcome I can hope for. One last reference I could find to Insight Enterprises is a list of software someone posted online, referring to Insight Enterprises CP/M. If this machine powers up expecting a boot disk, I'm probably hosed. If it has a system monitor I can drop into, then at least I can explore a bit that way. I presume hooking up a floppy and trying to boot, say, a Ferguson CPM disk probably won't work.
I'm not seeing any shorts in the board for power.. but I'm wondering if I could attempt powering up with just 5V connected to start. The -12v +12v thing makes me nervous, in case I've gotten something wrong.
Anyway, wish me luck
Pics of the board are here, along with dumps of the ROM.
Google only turns up a few references, mostly ads and a mention in Microconucopia.
Since there is zero documentation, my strategy is as follows:
1) Backup the EPROM
2) Trace the four pin power connector
3) Trace out the video, in hopes of finding a composite out I can tap into.
4) Hook up power and monitor and see if we get anything.
5) Figure out how to connect a parallel ascii keyboard, which the ad says this machine can handle.
I've already done 1), and 2) seems pretty straightforward. I knew where +5V was on most 74xx devices, so I used my DMM to trace that to pin 1 of the connector. Ground you can see connected to the ground pin of those chips and to the ground plane that runs around the board, so that's pin 2. I made a guess that there wouldn't be -5V on a board this late, so the other two voltages had to be +12V and -12V, since we have serial I/O. I used my DMM and confirmed VEE on that MC1488 links to pin 3, and VCC to pin 4 of the power connector. So I think I've got that solved.
For the video, I'm using my experience from fixing up my Dynalogic Hyperion, which seems to use a similar design for video. There is a CRT8002 attributes controller, and if it's like the Hyperion when it's in text mode all the text has to pass through it and out the VID pin (pin 1). So I've been tracing that out and it does seem to land over where the video componentry is.. it runs through a 7486, 7406, some resistors, etc and then takes off halfway across the board. Haven't followed it the rest of the way yet. I strongly suspect J9 is where video comes out, given its proximity to the CRT controller, static video RAM and transistor. I don't see anything about colour, so I presume it's probably like the Ferguson - it might have some ground pins, composite out, and then horizontal and vertical sync for a monochrome TTL monitor. Figuring out which is which might be tricky for me but i'm looking at other similar designs for clues.
The keyboard is the tough one. I don't think the header for it is J1, J2 or J4.. those are 34 pin and I think are for floppy. I think J10, J11, J12 and J13 are serial related. J6 or J8 is probably SASI. J7 may be the fourth floppy controller. So I'm kind of dialed in on J5. If I'm right, the trick will be figuring out where the strobe and ASCII bit pins are.
I think my odds of getting this thing to even flash up are 50/50. Comparing the ad photo to this board, I can see the ICs are not in the same positions. I'm not sure if the ad photo is of a prototype that later got changed into what I have, or the other way around. I suspect the other way around because this board has a handwritten 'IE-118' serial number and a bunch of jumper wires. If it's a prototype, it may simply not work.
Powering it up successfully may be the best outcome I can hope for. One last reference I could find to Insight Enterprises is a list of software someone posted online, referring to Insight Enterprises CP/M. If this machine powers up expecting a boot disk, I'm probably hosed. If it has a system monitor I can drop into, then at least I can explore a bit that way. I presume hooking up a floppy and trying to boot, say, a Ferguson CPM disk probably won't work.
I'm not seeing any shorts in the board for power.. but I'm wondering if I could attempt powering up with just 5V connected to start. The -12v +12v thing makes me nervous, in case I've gotten something wrong.
Anyway, wish me luck
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