NCE Illuminator CV Programming Problem

[JOHN BRUCE III]

I'm trying to modify the brightness CVs 140-142 on an NCE Illuminator.  This has been programmed to address 690. Woodland Scenics stick-on LED plugs have been installed in the W/G and Y ports. When I turn power on, the LEDs come on at full brightness. I can turn them off by doing SELECT ACCY from the Power Cab and choosing 1 or 2. So I know the Illuminator is correctly installed and programmed to the address.

 

If I follow the instructions in the NCE doc for either Signal Ops programming or Loco programming and try to program CV 140 or 141 on device 690, it does not respond to any value, and it remains at full brightness. I've tried to program it as loco 690 or signal 690, and I get the same result.

 

I've put in a message to NCE tech support, but their response is spotty, and I'm wondering of anyone here has any insight.