You need to check S-7 (RADF/Platen open close detect switch) and S-12 (RADF open close) in test mode. Sounds like one of these 2 have gone bad. S12 is on the ADF, and S-7 is on the main body under the rear cover. I have had both of these go bad, S7 from a paper clip dropped onto it, and S12 for no real good reason. 03 mode FAX LED ON, 5/F checks S-7, 7/D checks S-12, and 7/C checks jam cover access. If all check OK then you probably need a new ADF main PWB. You may also want to check/verify that your 5vdc supplied to the ADF is very close to 5.1vdc, if a little higher or lower it can cause the sensors to misread. Emujo
Thank you sooo much for your help. I have found that we have the service literature in our database & I'm tryimg to follow your suggestions within the manuals but I'm having difficulty finding the area that references the sensors as "S-7", S-12", ETC. Are those references in the service manual, handbppk or parts lists? All I can find is "things like "OPNSN" which would be the ADF OPEN SENSOR. AGAIN, THANK YOU FOR HELPING ME.
The 03 mode (input/output) is covered in the handbook. Basically, you want to power up in 03 mode, when ready, press the start button, this should bring up 2 columns of A-H. Press the FAX hard button to light it green. Now hold down the #5 key and open/close the feeder. The F icon should alternate from lit to out if the sensor is working properly. Next hold the #7 key, now, D should change as feeder is open/shut. Again hold down #7 key and open close the jam access cover, C should alternate. Emujo