[jascha]

That is truly amazing and I will build an adapter and try it out. Thanks so much for this circuit and for your time to help. Indeed a shame that our modern programmers cannot program old PROMs as you say but that’s the trouble with technology... it moves on and it’s up to us to fight back and challenge the modern times so we can keep these vintage machines running for many years to come. They are unbeatable if set up to optimum alignments!