Thanks a million, Mike, for scanning and posting this. I purchased this fix for my Altair way back when for $15, and it?s been one of those things that I?ve never been able to find online. I never purchased the Parasitic Engineering power supply fix, but I have found it online. The Parasitic Engineering clock fix has eluded me until now. BTW, IIRC, the PE clock fix worked excellently and I never had any clock related issues after installing it. The S-100 bus, the weak power supply, not enough slots, all those wires on the bus, all gave me plenty of headaches, but the clock fix worked great! smp - - - Stephen Pereira Bedford, NH 03110 KB1SXE