MP9001 Tandem Tray

**tcs04** · 06-25-2010

I have a strange one on a new MP9001 installation.

When the right hand Tandem Tray runs out of paper the left tray comes across before the right tray lowers.

The Right tray doesn't seem to drive down at paper end. I have seen the lift motor drivng in the "down" direction, when the tray reaches the top with paper in place it drives down about 10mm then up again, so the drive circuit must be working.

I have swapped feed stations 1 + 2 to eliminate them as the cause and the tray sensors all seem to give the correct signals in input mode.

Ideas??

**teebee1234** · 06-25-2010

The tray doesn't 'drive' down, it lowers on its own weight (there is a dampener that lets it fall slowly). The lift motor does reverse, but if the tray doesn't lower then the cables go slack. Check for any drag on the sides of the tray as bent side guides are generally the cause of this. Also check the the slots where the tray lift arms go through the frame to the lift cables, make sure the arms or attachment points are ok.

After rereading your post, I think you're saying that the tray doesn't even try to lower and the left side starts to move. It sounds like a sensor issue, have you checked the tray home sensor on the rear left side (as you face it from the rear)? I've seen those knocked out. I'm just not sure though that would cause this problem.

**tcs04** · 06-26-2010

Originally Posted by teebee1234

The tray doesn't 'drive' down, it lowers on its own weight (there is a dampener that lets it fall slowly). The lift motor does reverse, but if the tray doesn't lower then the cables go slack. Check for any drag on the sides of the tray as bent side guides are generally the cause of this. Also check the the slots where the tray lift arms go through the frame to the lift cables, make sure the arms or attachment points are ok.

After rereading your post, I think you're saying that the tray doesn't even try to lower and the left side starts to move. It sounds like a sensor issue, have you checked the tray home sensor on the rear left side (as you face it from the rear)? I've seen those knocked out. I'm just not sure though that would cause this problem.

When I say "Drive" I mean the Motor should turn to allow the tray to lower, but is not switching on at "paper empty". It does, however do the check (IE reverses and raises when the paper reaches the pick up roller).

The torque limiter on the tray is just to stop the plate slamming down when the tray is pulled out with paper loaded. I have heard of these failing but the cables don't slacken which seems to confirm motor drive as the problem.

All sensors are in position and seem to have the correct outputs in 5-803. If lifted by hand the tray lowers properly under it's own weight.

**sakura** · 06-26-2010

There are series of sensors (interrupters) which control/help to control all of the movements of the gates and other thing in a tandem try. Check them out first. There is may be one of the sensors failed. Also check all metal plates for any bends. If "walls" were bent they are not allowing bottom plate to move down. Just strait them up and check if it moves down when empty freely.

**tcs04** · 06-27-2010

Originally Posted by sakura

There are series of sensors (interrupters) which control/help to control all of the movements of the gates and other thing in a tandem try. Check them out first. There is may be one of the sensors failed. Also check all metal plates for any bends. If "walls" were bent they are not allowing bottom plate to move down. Just strait them up and check if it moves down when empty freely.

All the above done,

With the left tray out and one sheet of paper in the right tray, it lifts, so the paper end sensor under the plate must be ok.

The tray does not over drive at the top, so all sensors on the feed station are ok, also, paper feed is fine.

The tray reaches the top, drives down briefly and then raises again, so the motor drive can operate in both directions.

I believe the sequence should then be:

Paper runs out when feeding, paper end on feed station detects this.

Tray "drives" down (Motor MUST turn for this)

Tray lift arm enters lower limit sensor.

Lower limit AND paper empty detected, this turns on shift motor in left tray.

I can only conclude it must be something to do with the lower limit sensor detecting "tray down"

I will investigate and report. (I'm SURE I've seen this before!!!!)

**tcs04** · 06-28-2010

FIXED! (Had the THINKING head on today!)

It WAS a poor connection between right tandem main plug / socket to CN265 A16 PFC Board and centre pin (5v Active High) of S31, Right Tray Down sensor. This fault was present from new (!)

Thanks for the input

**df3036** · 06-28-2010

For those that have the Rear Fence bow, This is our fix... Rivit a piece of flat bar to the back of the fence and just cut out the metal strip in the bottom tray. Never bows again and the tray drops fine. When the machines are traded in, remove and reuse. Most of the tandem trays are the same.
Rear Fence..jpg