UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Timbucus · 7th Nov 2020, 12:34 pm

Sure enough pulling out the 8154 restores Graphics on by default on both VDU cards - so the 8154 is no longer pulling down the lines until I actually set OUTPUT mode on the A port explicitly - note that nothing has been added or taken away to from the MK14 as the caps were fitted on the Orton View and this is with my SOC VDU. There are no pullups on that just direct drive into IC8 (the L157) for Graphic mode select and IC1 (the rare and expensive L86) for screen Invert. The Orton View has pullups on all the Video control lines.

7th Nov 2020, 12:34 pm	#826
Timbucus Octode Join Date: Mar 2019 Location: Barry, Vale of Glamorgan, Wales, UK. Posts: 1,364	Re: Mk14 vdu Sure enough pulling out the 8154 restores Graphics on by default on both VDU cards - so the 8154 is no longer pulling down the lines until I actually set OUTPUT mode on the A port explicitly - note that nothing has been added or taken away to from the MK14 as the caps were fitted on the Orton View and this is with my SOC VDU. There are no pullups on that just direct drive into IC8 (the L157) for Graphic mode select and IC1 (the rare and expensive L86) for screen Invert. The Orton View has pullups on all the Video control lines.