Top cover switch shenanigans

**Kyo fan** · 09-15-2019

So, I was working on ECOSYS P3055dn where i replaced clutches to resolve paper jams. I replaced those countless times, and never had this happen on any Kyocera device. After putting everything back together, the printer doesn't power on. I figured out it was due to the top cover (interlock) switch. Opening the top cover, it powers on and (of course) asks to close top cover. Once I press that switch, the power cuts off as if you would pull out the power cable. I managed to find a spare switch, but i got the same result with it.

top cover switch 2.jpg

I know that eventually it's gonna come down to engine pwb (since the switch connects to it), or maybe the power source pwb. What i really want to know here is why? What could have caused this switch to kill power here? The 24V are present, and I've triple checked boards, wiring and connectors. The only difference here are the three new clutches (registration, and two on the drive feed).

**djs9164** · 09-15-2019

This is not meant to be sarcastic. I have worked on many different models over the span of my career, and Kyocera machines are the most fickle when it comes to reasembly. I often find myself saying " what did I do" . Good luck. It's time check all connections for a 5th time.

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**tsbservice** · 09-15-2019

Well it may be pinched or shorted wires somewhere else.
When you close top cover(activate switch) there will be some initialization of various parts. I will start checking timing charts in Service Manual to see what they are and try to trace them out.

**blackcat4866** · 09-15-2019

Originally Posted by tsbservice

Well it may be pinched or shorted wires somewhere else.
When you close top cover(activate switch) there will be some initialization of various parts. I will start checking timing charts in Service Manual to see what they are and try to trace them out.

Exactly my thought. Typically door interlocks take 24vdc and send it back to the controller. The controller then applies that same 24vdc to other components. If perchance somebody (not you of course ... but SOMEBODY) were to pinch a clutch wire to frame ground, that person would get very similar symptoms to what you're seeing.

It's time to re-do what you did, and make sure the right connectors got plugged into the right components, and no wires got pinched to frame ground. Also check that you're new clutch does not meter from either lead to frame ground. There may be an internal short in your new clutch. Simply unplugging the clutches may be the simplest diagnostic tool.

These sort of issues are satisfying to diagnose, assuming you do find the culprit. =^..^=

**Phil B.** · 09-15-2019

Originally Posted by blackcat4866

Exactly my thought. Typically door interlocks take 24vdc and send it back to the controller. The controller then applies that same 24vdc to other components. If perchance somebody (not you of course ... but SOMEBODY) were to pinch a clutch wire to frame ground, that person would get very similar symptoms to what you're seeing.

It's time to re-do what you did, and make sure the right connectors got plugged into the right components, and no wires got pinched to frame ground. Also check that you're new clutch does not meter from either lead to frame ground. There may be an internal short in your new clutch. Simply unplugging the clutches may be the simplest diagnostic tool.

These sort of issues are satisfying to diagnose, assuming you do find the culprit. =^..^=

+3 to pinched wire.. as BC said triple-check the wiring harnesses.. the connectors to BD... bust it down to basic machine and go from there..I saw one tech that had worked on Ricoh LCT and messed the connector up... nothing would happen until that tray was activated and started to lift the tray.

**kjg** · 09-16-2019

I'm going to throw in with the rest. 24v component shorted to ground somewhere. If not a pinched wire, the perhaps a screw that has fallen in behind the engine PCB. Time to disassemble and re-assemble taking particular note of wiring and components. We all have been there my friend. I wish you the best.

**djs9164** · 09-16-2019

Not the same model but... I took the side door off of a 4002i and somehow the pin on the intermediate male-male conector got pushed more to one side. This gave a constant door open signal.

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**Ropariva** · 09-17-2019

It’s easy to bend a pin in a plug. I’d pull every plug and check the pins are all present and correct.

**Kyo fan** · 09-19-2019

Finally managed to find the cause yesterday. After yet another careful tear down and inspecting every single wire for possible pinch or short, i slapped myself for making a rookie mistake. You see these two connectors:

connectors.jpg

Well, they are the same and can fit both places. I was in a hurry connecting engine pwb, and managed to swap their places. Than it was covered with the rest of wires making it look ok. Moral of the story: Don't rush it, and don't follow any logic here. The top connection is for the conveying fan below, even though it's more convenient to plug it in the bottom spot based on the length and shape of the wires.

Thank you all for tips and hints.

**djs9164** · 09-19-2019

I always take a few pictures before I disconnect. It sometimes can help me n these situations. Glad you found it. Keep techin'.

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