PDP 11/45 Further success! (and a question)

Hi All, I replaced the UBC today (I found a serviceable spare of the same version in our works stores, last tested 1994....), and I can now key in a program, examine it and run it. I now need to concentrate on the PSU, before I start putting the rest of the cards back. I must also repair my UBC, in case work decides they want theirs back (unlikely, but you can never tell with bean counters). Now a question, I used the light flasher program: location contents opcode 001000 012700 mov #1,r0 001002 000001 001004 006100 rol r0 001006 000005 reset 001010 000775 br -4 and it will run, however, I don't see the data lights "chase" across the console. If I single step, the program performs as expected, with the data lights going across the panel (data switch in "Data Paths" position). Also, if I run the program and halt it, the light appear at a different data bit depending on how long I let the program run (I can continue the program and it will move to a different bitn at the next halt). Am I doing something stupid, or are the bulbs just too slow to display the data? (I suppose it could be a function of the power supply fault, but I don't think it would manifest itself in this way). Thanks Jim. Please see our website the " Vintage Communication Pages" at WWW.G1JBG.CO.UK