asked Feb 28, 2010 at 7:09pm
Hp HP LaserJet 4

HP 8150 optional tray 4 problem

I have a 8150 printer jamming at the entry ot the vtu unit. It starts printing just two or three pages fine then the paper crumbles and jams like it went in crooked, and the paper jam in the VTU causes to push the VTU and getting open.

I replaced the pickup assembly and vtu unit and I still get the jam at the entry. Any help would be appreciated.

You replaced the two main items that could cause this problem. Only other thing I can think of are the dividers that secure the paper in the tray so the sides and back are firm with no movement.
by dmzcompute on Mar 1, 2010 at 5:00am Add comment
Hi dmzcompute,
That is a good point you mentioned, I will check it tomorrow but the original problem was tray two and three and after around 100 pages was getting paper jam (tray 2 or 3) so I replaced paper pick up asm and after this replacement customer called back for tray 4 jam but I am not sure tray 4 problem really was from before or after replacement for tray 2&3 now, do you think any correlation between tray 4 and the other tray regarding tray 4 problem?
by paul_es on Mar 1, 2010 at 3:20pm Add comment
Does the paper reach the paper input unit or does it get jammed before it even gets out of the tray 4 VTU?

I'm wondering if the new paper input unit might work fine for trays 2 and 3 but have trouble accepting paper from the VTU in tray 4 since it does enter the paper input unit from a slightly different angle coming from tray 4.
by AngryatQuality on Mar 1, 2010 at 3:52pm Add comment
Knowing that you replaced the PIU there is one item when you put everything back together that could have had a impact. When you reattach the lower door which has the slot that the paper goes thru from the VTU for tray 4 there are 2 notches that fit into the frame of the PIU when you reassemble. They are towards the middle of the door and if they are not in the frame but laying outside of it, it could effect the ability of the paper to feed from the VTU thru that door. It does not effect tray 3 since that feeds from the inside of the PIU and up the channel, but paper feeding from tray 4 goes thru the slot at the bottom and if bowed out will cause it to become jammed. Hope this helps.
by dmzcompute on Mar 1, 2010 at 6:10pm Add comment

If I print 10 pages, the first page is ok the second to fifth pages go out of second vtu’s sensor and jam like accordion. And the other thing it my be important is that if the printer is off for one or two hours then turn it back on for the first time I print 50 pages no jam and if try to print after one hour when the printer gets warm it starts paper jam.

To make sure everything I put it back together I uninstalled the PIU and installed it again, because I was thinking like you but I did not find anything wrong regarding the lower door with slot.
by paul_es on Mar 1, 2010 at 7:06pm Add comment
Seems like a strange problem. I've replaced a ton of the printer's paper input units in the past and usually that is where the problems end up.

Might want to check how you put the lower right hand side cover back onto the printer. The one where the door is attached. There are two clips that need to be in the right place along the inside edge. These clips go into the paper input unit.

With the right hand side bottom door open, the one below the tray 1 input door. If you look just to the inside of those two white plastic rollers towards the print body, there are two clips which should be in the paper input unit. I have missed those in the past

Might want to try legal paper from that try to see if you have the same problem. If you do not, I'd guess it has something to do with the paper input unit still as the leading and exiting edges of the paper will be in different spots. If the problem continues then I guess I'd look elsewhere, maybe registration assembly if it's even reaching that far.

As far as it building up heat, the only thing I could think of is the fuser.

Hope any of that helps.

by AngryatQuality on Mar 2, 2010 at 8:00am Add comment
Thanks all for your help.
The printer is fixed, first I used tray 4 and VTU with another printer to find out if the tray 4 or VTU are the source of problem and I printed more than 100 pages without any jam then I replace formatter board, I used formatter from original printer to find out if the firmware(ROM) causing this problem so that was ok, then I replaced PIU and that new crazy PIU was the source of problem and I printed more than 200 pages without any jam but I do not understand how PIU which was perfect for tray 2&3 can make problem for tray 4 because tray 4 using only top portion of PIU which is common paper path for tray 2&3 and 4.
by paul_es on Mar 2, 2010 at 5:07pm Add comment
It uses the bottom part of the PIU to first enter the path which is not used by tray 3.
by dmzcompute on Mar 2, 2010 at 6:08pm Add comment
Glad the problem is solved.
by AngryatQuality on Mar 3, 2010 at 9:35am Add comment