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‎10-26-2025 01:37 PM - edited ‎10-26-2025 01:38 PM

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I chanced upon a previous post from five years ago concerning a situation where a LaserJet 4050TN would not recognize the presence of Tray 2 when fully installed. A reply by a poster AIS77 offered the suggestion to adjust the tension on the leaf springs that engage the contacts on the controller board in the paper feed module as a remedy. I believe I am experiencing a similar problem with my LaserJet 4050TN and would like to attempt that fix myself. Given that this is a 25-year old device, and parts become brittle with age, I would like to know the path of least resistance in disassembly to avoid possible mishaps. In other words, could someone with experience with this process offer instructions with the minimum amount of disassembly required to get to the leaf springs in question?

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‎10-27-2025 02:50 PM

HP Recommended

My experience with this product is that more likely the switches that the metal springs press against have failed not the springs. Unfortunately there is no real shortcut to getting into these systems. To access the bottom tray you must remove the top and all side panels and then there a bolts that separate the printer body from the tray assembly.

 

You can test the buttons by removing the tray and pressing the springs to see if you get any response on the control panel. 

 

The switches are available from Digi-key, you will just need to make sure you get the right ones and then you will have to unsolder the old ones and replace them. Thankfully the boards are pretty durable and I never had an issue with traces lifting during the process.

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‎11-11-2025 06:34 PM

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Continuing with this effort. I've got the printer disassembled and organized and the replacement board ordered. Ran into one snag: As I was removing the pick-up assembly board above tray 3, a piece came loose that I have not been able to identify to re-attach. See the pictures. It was loose in the right-front housing of tray 3. I have not found the part in any of the parts diagrams I downloaded for the 4050TN. Any help identifying the part and where it re-attaches would be very much appreciated.

 

Loose partLoose partArea where found loose

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‎11-29-2025 02:28 PM

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Success! Forged ahead on a wing and a prayer. Tray 2 is now recognized.

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