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

SiriusHardware · 16th Apr 2018, 1:06 pm

Fast work

I didn't have time to try to relate the mod info to the issue II diagram but it doesn't surprise me that the gate pin numbering does not match the mod document.

Typical.

S.O.C. were fond of other stunts as well, such as ignoring the D0-D7 and A0-A7 order of the data / address pins on RAM ICs and tracking / using them in whatever order it was most convenient to do so.

This didn't affect the operation of the circuit (it doesn't matter if bit 0 of your data is stored in physical bit 6 of a completely different physical RAM location, as long as it is also recovered from bit 6 of the same RAM location) but it made tracing / faultfinding bus faults tiresome in the extreme.

So, will you now work these changes into your replica?

16th Apr 2018, 1:06 pm	#8
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,556	Re: MK14 schematic revisions Fast work I didn't have time to try to relate the mod info to the issue II diagram but it doesn't surprise me that the gate pin numbering does not match the mod document. Typical. S.O.C. were fond of other stunts as well, such as ignoring the D0-D7 and A0-A7 order of the data / address pins on RAM ICs and tracking / using them in whatever order it was most convenient to do so. This didn't affect the operation of the circuit (it doesn't matter if bit 0 of your data is stored in physical bit 6 of a completely different physical RAM location, as long as it is also recovered from bit 6 of the same RAM location) but it made tracing / faultfinding bus faults tiresome in the extreme. So, will you now work these changes into your replica?