UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - A Simple Programmer for TESLA "MH74S-" bipolar PROMs

SiriusHardware · 6th Oct 2019, 10:48 am

I'm away from base and I don't have all my usual MK14 related material to hand, but if you are referring to the Arduino / SOC programmer hybrid posted up by 'Slothie' in the now closed thread I mentioned above, I believe he drew that before we realised that there were notable differences between the DM and MH devices.

If developed further, i,e, if the Arduino firmware to support that project had ever been written, it would have worked as a standalone DM74S571 programmer, but not as an MH programmer, so Slothie didn't take it any further.

I think the problems we had were

-Uncertainty about the programming voltage and programming pulse timings, although I think that was eventually thrashed out in that closed thread

-An apparent difference in the physical / electrical programming scheme which suggested that the SOC hardware circuit could not be used, unmodified, to program a Tesla MH74S571 even if the programming voltage was correct and the software timings were changed.

That's why your project is of such great interest, and I'm grateful for the time you have taken to put it together and post it here.

6th Oct 2019, 10:48 am	#8
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,547	Re: A Simple Programmer for TESLA "MH74S-" bipolar PROMs I'm away from base and I don't have all my usual MK14 related material to hand, but if you are referring to the Arduino / SOC programmer hybrid posted up by 'Slothie' in the now closed thread I mentioned above, I believe he drew that before we realised that there were notable differences between the DM and MH devices. If developed further, i,e, if the Arduino firmware to support that project had ever been written, it would have worked as a standalone DM74S571 programmer, but not as an MH programmer, so Slothie didn't take it any further. I think the problems we had were -Uncertainty about the programming voltage and programming pulse timings, although I think that was eventually thrashed out in that closed thread -An apparent difference in the physical / electrical programming scheme which suggested that the SOC hardware circuit could not be used, unmodified, to program a Tesla MH74S571 even if the programming voltage was correct and the software timings were changed. That's why your project is of such great interest, and I'm grateful for the time you have taken to put it together and post it here.