(thanks again, Peter!!!!)
... and now back to our regularly scheduled programming...
The SL2 loop oscillator output test point is frequency-stable. As SL2 output moves from 30 MHz (setting x.x00 000 Hz) to 20 MHz (setting x.x99 999Hz), it's amplitude drops by about 50% but at each test point, SL2 output frequency matches the expected values in table A-5 and does not vary.
The test instruction paragraph 5-13 does not indicate a minimum signal level for SL2 oscillator output. The "wandering" problem at the 11707A 20-30 MHz output doesn't appear to be correlated to SL2 output level (that is, it wanders regardless of the bottom 5 digits.) Also, the wandering is wider in range (up to 300 kHz from what I can tell) than SL2's available tuning range.
SL2 oscillator output is available at two different test points - A2TP6 (callout 27 in figure C3, and requested in the test instruction paragraph 5-13), and XA15-2 pin 14 (callout 38 in figure C3). I found XA15-2 easier to access (A2TP6 is buried under two horizontally-mounted plug-in boards behind the front panel DCU assembly); XA15-2 is a pin of one of the card edge connectors (not particularly easy to reach, but certainly easier to see.)
Next stop will be SL1 output (which from what I can tell sends signal to the 11707A 20-30 MHz test connector, so hopefully the problem will then be somewhat isolated.
