RICOH SP5300-No Paper

[semi]

I 've got a Ricoh SP 5300 Showing no paper either in the main tray and the bypass,main tray will lift show paper then immediatly lower back down ,showing empty.I think it's a badged Kyoceara.cant see anything obvious in the service manual,mind you it did have a 670 code just before-I'm learning towards the IOB/BICI ,anybody else got any ideas?
Thanks

[mikadonovan]

I have had the sensor that detects the tray up position fail on the 4100 series more than once. Maybe pull out the toner cart and tray 1, then tilt the printer on its back and look inside, should be a couple of photointerrupters right there.