[2300n] cartridge not seen after fixing sticky solenoids

[Wbdsgnr]

So my trusty old LaserJet 2300n has been working great besides the occasional paper-jams. To fix this problem i cleaned up the solenoids that had become very sticky. I put the printer back together and suddenly the printer no longer sees the cartridge and says I should install one. 

How does the cartridge sensing mechanism work? Is it merely that chip thats  being read by the laser unit? Or is there some other little switch that i've been failing to see.  I have been careful to not static-discharge on the chip.

I've ordered a new cartridge but i can't shake the feeling it's not the cartridge but something i'm missing when putting the printer back together.  I'm not getting any other errors and a cold reset didn't solve the problem either.

[Valsimot]

Double check all connectors on the engine controller PCA. The toner chip reader is connected to the engine controller (callout 3).

[Wbdsgnr]

I double checked the cables and did a connectivity test with a multimeter, but no luck. The e-label reader is attached properly.  

[Valsimot]

It's probably something minor if you haven't yet I would recommend you to repeat all the steps, remove all parts again and put back together.

[Wbdsgnr]

Ok so i narrowd the problem down to the main motor not turning. After manually rotating the biggest gear, the cartridge latches and is detected normally. When i then print something I hear the solenoids clicking but nothing is turning (only the little motor secondary motor), after which i get a 13.01.00 paperjam error.

On start-up all that turns is the little secondary motor, the big main motor never turns as far as i can tell. Is there an easy way to debug this? I have a soldering iron and oscilloscope if necessary 🙂