View Full Version : Northstar Horizon cpu question

March 10th, 2010, 01:06 PM
I bought a Northstar Horizon, on the Z80 board it has a daughter card that has HSC C016 written on it. This card has a cable that goes out to a db25 connector on the back of the machine. There is a set of dip switches on the card. I'd like to know what this is? What should be or can be connected to the DB25? What do the dip switches do?


March 15th, 2010, 07:28 PM
It could be a hack to allow a person to access the processor via some sort of monitor program or in-circuit emulator or some sort. Useful for diagnosing problems if you can't boot a disk or get a terminal I/O running. This is just a guess, but without a picture of the chips I can't say for sure. Does the computer work?

March 16th, 2010, 07:36 AM
It was reported to work, but so far doesn't boot. The floppy does seek, so I'm thinking that the processor is working and accessing the floppy at $e800 (I think, from my memory). Since no proms are installed on the processor card, I'm assuming that it does not do any type of boot testing. Other than the front led lighting there is no indication besides the floppy seek and no serial bus activity until it finds a diskette, correct?

March 16th, 2010, 12:12 PM
I am assuming your're hooked to the correct serial port, etc. There is a user manual that has a walk through process.

Further I would check the voltage regulators on the motherboard (back left) and the 1489/1488 chips (back middle IIRC) to be sure everything is OK.

The daughter boards with the serial connector needs more investigation to get a full picture of what's going on with this system.