As a quick update - putting the SGS 365ABI back in my machine allows the PI-Programmer to run at full speed fine although still with the longer reset... go figure. I also tried one of the four TI marked 365AN I have bought for the VDU circuit and that works fine as well. There must be some other issue though as it affected SH so badly. The review of the kit in PCW issue 2 (Apr 1978) lists different values for some passive components - perhaps we also need to look at those - I went with the list in the manual maybe SH Issue II has these older values?
