HP 41.03 errors on HP laserjet 4050TN

Occasional without any method to the madness this printer will show 41.03 unexpected paper size on the control panel. tray 2
Steps I have already taken
1. Verified that the paper tray is set to letter(both sets of tabs)
2. Replaced the tray completely. The top plastic clip on the right side(there are three off them) would not lock into place. read somewhere on the net this could be my problem.
3. Reset the printer settings.

This printer is setup to print from a windows 2003 server with an IP printer installed and its using the 4050 pcl 5e driver

I'm at a loss at what to try next.
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HOMEMADE VAPORIZER SOLDERING IRON

I'm having them try the other tray to see if the error follows to another tray
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Shemale Video

There is a small PCA board which controls paper size , etc. That PCA is a common failure part and will detect incorrect paper size.

On the 4050TN it's a bit difficult to replace that PCA (you have to remove all the outer panels, separate the top half of the machine from the lower trays, and then remove the top plate covering the lower trays to remove & replace the PCA board). We do sell that PCA board at PrinterTechs; 866-352-7108.

Ok, So I had them take all the paper out of tray 1 and try tray 2 and it works.

Is there a sensor? or a separate board for each tray?
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POT

Sounds like a sticking solenoid ; over time the sound dampening pad gets "gummy" and causes the solenoid to stick intermittently. On this model it is a big job to disassemble and access the solenoids for repair or replacement; there is one solenoid for each paper tray's pickup assembly.