PLC5/20 output issue

OK, I'm stumped- I have a problem with a 120 volt output staying on on a particular AB PLC 5/20 Remote rack- older system, output card is Cat#1771-OA, eight bit 120 volt output, turning on some pneumatic solenoids, Outputs 0 and 3 stay hot even though looking at the program they are OFF. Swapped cards, same problem, Using the PLC to force the output ON lights the output indicator LED on the card, forcing output OFF turns the LED on the card off, either case the output is on, voltage stays at 120VAC. Swapped the Rack, suspecting a backplane issue, still have the same problem! Looking at the data table, the output should be off, but I have voltage! Disconnected all field wi=ring from this particular rack, connected a seperate 120 volt source to the problematic card, still have two outputs that stay on, no LED. Does anyone have any ideas? checked backplace power supply, looks Ok at 5.01 VDC

I've usually traced this to a bad common. Is you 120vac common tied to ground?

Common

Yes, I checked bact to the transformer supplying PLC power, Looks like neutral is tied to ground OK, same potential. I did see on an older post that Ron suggested my load might be too low, I'll try a load resistor in parallel with my solenoid valve, but I sure thought the solenoid would be enough of a load by itself. Thanks for the response,

The 1771-OA is a Triac Output, it will have some leakage current, and will show voltage with a SSVOM, if they are not loaded enough by the field device.

Installation Instructions:

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1771-in080_-en-p.pdf

Technical Reference:

http://literature.rockwellautomation.com/idc/groups/literature/documents/td/1771-td182_-en-p.pdf

Have a look at page 31 of the Technical Reference.

Stu.....