"I have an HP IIP that goes through the "05 Self Test" mode but hangs when it gets to "02 Warm Up." The only thing I ever hear run is the fan. I am not getting any error codes otherwise. If I try to send a print job to it in this state, it seems to take it and the On Line indicators light up, but it won't print. Based on what I've read in the FAQ and in the archives, I'm guessing it is the DC Controller. I re-seated the connections going to the DC controller PCB and the power supply and everything else visually looks good. I do not have a service manual for this unit.
Can someone tell me how to test the DC controller to see if it is defective or maybe shed a little light on what may be causing the unit not to make it to the "ready" mode?"
Any number of simple faults can result in the warmup sequence not completing. Check these first before suspecting a blown power supply or controller.
It may indeed be as simple as a burned out bulb or broken door interlock.
(From: Dave Lee (email@example.com).)
Here is what I found in my notes concerning your very same problem, Hope it helps......
New "Service Today" from Parts Now, volume IV, number 1, issued in Feb 95 is devoted to the "LX" engine units, IIP/IIP Plus/IIIP Series, the Cannon LBP-4, Apple Personal LaserWriter. Lots of good stuff, error 50's, error 41's, fuser upgrades, "moaning", other squeaks etc.
Here is what it says:
If hung on "02 Warming Up", trouble may be caused by cables on the door wear and tear. Also look at DC Cnt PCA, dual I/O, formatter PCA. Now also look at the solenoid for the MP pickup roller assembly. This can cause the 'hung 02 Warming Up' error if an open occurs in either the solenoid cable, or solenoid coil. To check, remove the formatter PCA in order to access the DC Controller PCA. Locate J209 on the DC Controller; pins 1 & 2 are the solenoid. Measure across the top of these pins, the correct reading is 200 ohms +- 10%. Replace the paper path door cable assembly, Part #RG1-1608-000 if the solenoid has high resistance.
(From: Jeff Churchvara (firstname.lastname@example.org).)
Experience would have diagnosed this one in about 10 seconds. I just didn't know what I was looking at.
I started reading the FAQ and figured the worst. At first, I did not have the service manual to go over this code. When I finally did get a copy, I started checking the voltages and did not have +24 V at the DC Controller PCA.
All of what I was reading said to defeat the door interlock. At first, this didn't make sense to me because the bar that should be attached to the door was instead, laying on top of the switch and wasn't even moving when the door opened. I didn't know enough not to look any further.
Once I realized the bar should've been attached to the door, I started looking for it's correct mounting. The screw holding the bar must have loosened up and over time it broke the mounting nut right out of the door.
I ended up resetting the nut (threaded sleeve) by adding a screw from the outside. Then I pinched it in place with a second screw when I re-anchored the bar. This made the bar pull away when the door opened and then correctly contact the interlock switch when the door closed.
I forgot the basics of troubleshooting when I posted this one and was making it more difficult than it actually was.
Thanks to all of you who responded and kept me looking in the right direction.