UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Gemini 80-Bus System

JohnBHanson · 13th Jan 2020, 1:24 am

A description of the circuit is given in section 1.2 of the hardware manual.

When you get the ***** M-F-B 2 System *****

The system could well be waiting for a boot floppy or the winchester to spin up.

Note also the boot hangs if you don't use the MFB version of the GM849 - possibly with the red LED halt light illuminated.

If you can upon power up without any additional presses of the reset button check the Z80 is producing M1 cycles - eg M1 pin toggles if you can.

13th Jan 2020, 1:24 am	#313
JohnBHanson Heptode Join Date: Aug 2009 Location: Worthing, Sussex, UK. Posts: 661	Re: Gemini 80-Bus System A description of the circuit is given in section 1.2 of the hardware manual. When you get the *** M-F-B 2 System *** The system could well be waiting for a boot floppy or the winchester to spin up. Note also the boot hangs if you don't use the MFB version of the GM849 - possibly with the red LED halt light illuminated. If you can upon power up without any additional presses of the reset button check the Z80 is producing M1 cycles - eg M1 pin toggles if you can. Last edited by JohnBHanson; 13th Jan 2020 at 1:33 am.