DIYer looking for help

[Jorabi]

Hi. I am pretty sure I know your problem. These machines have a really bad know issue with the duplex guide and gate on the upper right door warping. Sharp made a modified guide and added little clear fingers to it to help as well. That's basically how you can tell.

Going by your bulletin, I have the old Reverse PG and no lower PG pawls.

This is a common issue. The easiest way to check is to look at the flat edge on the bottom of the black guide. It it should be straight and even. If it's not replace it.

I am looking at the bottom of the reverse PG and it looks straight, using the steel below it as a guide. Here is a picture.

Reverse PG.jpg

Should I replace the PG and add the new pawls as the bulletin says, or wait until I confirm there are no other problems, using simulations?

The picture you posted is of a fuser lower picker finger. You really need these. Without them paper will catch the top gate on the fuser and jam.

Thank you. The service manual calls it "Lower separation pawl" as Zootech mentioned. There was a hole where the 4th one belonged, so I installed the loose one there. That wouldn't be causing my POD1_S and APPD1_N jams, would it?

[ntbann]

This could be a sign that the exit unit is going bad.

[repn1999]

Your picture is from facing the guide. Look at it looking at the flat bottom side and look to see if the back edge that faces the door when it is attached is straight. It warps in the center and bows out. Could be a delivery unit but I'd check the guide first.

[fireater]

Is there an online forum more appropriate for non-professionals to get troubleshooting help? I have an MX-3501N in my home which was given to me by the local library. It has been working fine for a year but now it isn't. I cannot afford professional service calls, but I am mechanically/electrically inclined and am hoping to find the problem myself with a little guidance. Thank you.

I wouldnt worry about firmware ... the little duplex gate on the side door that flips up as you close it gets stiff in the bushing .. clean bushings with alcohol.. leave dry do not lube.
the pawl in the fuser should be replaced. also check for gouges in the rollers from the pawl. the rollers need to be good.

[Jorabi]

the little duplex gate on the side door that flips up as you close it gets stiff in the bushing .. clean bushings with alcohol.. leave dry do not lube.

Should the flip-up gate with all the fingers, snap all the way closed (down) when I raise it with my hand and let go? It is only goes down about half way on its own, as if the spring on the left end of the rod is not tight enough.

[repn1999]

The gate has been revised. Usually cleaning the shaft and bushings with alcohol fix that. It doesn't have to be perfectly down tight but down enough for the frame to catch and open it when the door closes.

[Jorabi]

The gate has been revised. Usually cleaning the shaft and bushings with alcohol fix that. It doesn't have to be perfectly down tight but down enough for the frame to catch and open it when the door closes.

After cleaning the shaft and bushings the gate flips all the way down on its own. I am going to reinstall the gate in the machine (I took it completely out to see if it was warped) and try it.