GREAT TO SEE PROGRESS! Keep up the good work Cory! yes, heads have to be close to work.. at least that is the way it was with the VRC drums for storage on the GEPAC process control systyems Ed# _www.smecc.org_ (http://www.smecc.org) In a message dated 2/25/2017 7:24:30 P.M. US Mountain Standard Time, coryheisterkamp at gmail.com writes: Some promising news on getting the LGP-30 up and running. With all systems stable, I tightened the head spacing on the three timing track heads (using brass 0.001" feeler gauges though I may have to go closer). This has resolved 'hanging' when hitting Start; it actually appears to execute for a cycle before toggling back to Stop for each press of the Start key. Of course without being able to see what's happening, it's likely just 'executing' garbage, but it's a solid first step. In Manual mode, keystrokes from the Flexowriter now trigger a Stop/Compute toggle for each key entered and status neons on the flip-flop cards are registering unique bit patterns as each comes in. I put the scope on the (rebuilt) clock generator card and we have good 'T' and 'T-bar' signals propagating, but still haven't licked the 'digital display' issue. After further probing, the display began to stabilize and the single line expanded into the proper 3 for Counter, Instruction and Accumulator, and eventually a bit pattern emerged for the Instruction. No signs of data yet for Counter nor Accumulator, and there is an extremely pronounced 'throbbing' and visible refreshing. Here's a video: https://youtu.be/Nhya46V-l70 System timing looks spot on (top trace), but I also see some 'throbbing' when putting my scope on any of the three timing heads which seems a little strange to me (example on lower trace). Here's a quick vid: https://youtu.be/JjRKDWVUyjA One thought is that the timing and short register heads are still too far off the drum surface for a solid signal, purely conjecture at this stage. -C