LJ 4, 41.x error, print engine failure and lock-up

[Lee_05]

LJ 4 printer, about 15 years old, light service: initially works fine for about 10 minutes, but after it's been on for awhile (~30 minutes), the READY, ON LINE and FORM FEED lights become steady-on and printer is unresponsive to any menu selection. Just prior to lock-up, I get a 41.x error code, to the effect of print engine failure . Must allow it to cool down before normal operation can be resumed. Any suggestions? I have the service manual. THANKS...Lee

[Repairatrooper]

This error could be caused by a bad fan that is causing the DC controller or power supply to overheat. Check that all fans are working and replace as necessary, if all fans are working, see the instructions below. 

Most of these errors are related to the laser scanner assembly and at the age of this printer that is not surprising. Does the printer operate with a fairly high pitched whine to it? If so the scanner motor might require lubrication. Removing the top cover will reveal the laser scanner. While it is not recommended to take it apart, you can, just be careful not to allow dirt or fingerprints to get on any of the optical elements. The shiny square on top of a circuit board is the scanner motor. You need to gently remove that top and use a drop of very thin oil on the shaft. You will not find these instructions in the manual as this part was considered non-serviceable and the advice I have given is based on field experience. Failure to exercise caution could result in a non-functioning laser assembly, you assume all risk of following these instructions.

[Lee_05]

Many thanks for your reply.  I don't detect anything suggesting rotational problems with the scanner motor.  The problem does seem to be time, or maybe heat, related, though.  Do you think this could also be related to the fuser assembly?  I'll plan on checking the scanner soon and report back.

[Lee_05]

(Replying to self...further thinking.)  I'm wondering if a scanner malfunction would also trigger the lock-up mentioned in the first message?  I can see how it could be responsible for the 41.x error, but don't know how extensive the diagnostic program is on the printer.  The exhaust fan is working fine so am eliminating that as a cause.  I hate to start throwing parts at this machine, hoping something will fix it!

[Repairatrooper]

On these older models the diagnostics is somewhat limited. If I was where you were, I would pull the power supply and look closely at it. Power supplies are one of the more common age failure components due to the heat. Fuser issues will almost always throw an error rather than just cause the printer to lock up. 

[Lee_05]

Good info; thanks.   i'll do a power supply check soon.  Meanwhile, as long as I don't keep the printer on longer than absolutely necessary, there are no issues.  I hate intermittents!

[Lee_05]

(Reply to self, others....)  The problem was the power supply.  A replacement P/S solved the problem!

Lee