I've been facing a persistent fuser error (50.FF.02) on my HP E87640 printer, and despite some progress, the main issue remains. Initially, trays 4 and 5 weren't detected, nor was the stapler or scanner functioning properly. After jumping the fuser board bypassing the relay, I noticed improvements: both trays are now detected, the scanner and auto document feeder (ADF) are operational, and the stapler works as well. However, I'm still experiencing the fuser error and there's no power to the motors that lift the paper from any drawer. I've confirmed that the fuser pressure motor operates with a 9V battery. The service menu indicates that the yellow, magenta, and cyan drums rotate, but the black drum does not. I've replaced the fuser PCA, which showed 'OK' in the status, so I doubt the fuser is the culprit. I've read that others faced similar issues even after replacing both the fuser and the main board. I'm wondering if either the reactor coil or the high voltage power supply (HVPS) could be faulty, or if I should consider both. Any advice would be appreciated!
3 Answers
Man, printers are the worst! They're like the divas of tech. Anyway, checking the connections on the main board is a good idea too, especially if they’re brittle. Just make sure nothing is completely disconnected. The reactor being faulty is possible but sadly a bit of a pain to test directly.
Wow, it sounds like you're really diving deep into this printer issue! From what you've shared, it seems like the fuser is probably working fine since the status is okay after the PCA replacement. It’s plausible that either the reactor or the HVPS is faulty. Have you tried running a maintenance program? Sometimes, that can reset things and help narrow down the problem.
I haven’t done the maintenance yet, but I’ll definitely check out some guides for that. Thanks for the suggestion!
You're going way deeper than most would dare with a printer! It’s a good call on the fuser PCA being okay. It might be a good idea to try swapping out the HVPS next, especially since the power supply affects multiple components. It's a common issue for them to go bad after many years.

Absolutely! It's frustrating, but I'm hoping I can get it sorted soon.