Fixes and answers from the field

By Raymond Cote

I would like to thank the techs that have contributed information about unusual problems and the resolutions that fixed them. So far, I have reviewed several field problems that were not able to be repaired using the standard Repair Analysis Procedures (RAPs) in the service manual.

 The first issue I’d like to share was submitted by a technician from New England, who complained about a copy quality issue on his Docutech NP-135 printer. The copies were described as picture-perfect, except for a number of lines that went in the fast scan direction (top to bottom). The lines (for lack of a better description) were evenly spaced 20 mm apart and varied in thickness from 2½ mm to 6 mm thick. Any print on the page was clearly visible and not distorted in any way. (Actually, I thought they were cute in the sense they reminded me of the thin Yankee stripes on the baseball uniforms!)

What threw the technician off was the first few copies delivered to the face-up tray had only a few lines on the page, but as it continued to run the lines became more pronounced and plentiful until the page had about 10 vertical lines. I think the term ‘line’ is not exactly the best description to use, but rather a band that resembled background.

The starting point in the service manual was with the Image Quality RAPs in section 3, page 152. Comparing the test copy to the copy quality defects, the “Background Band, 11mm wide” RAP was used: The description of the copy-quality problem was close, but not an exact match. The RAP describes the band as being 11 mm wide and the test copy was about 2 1/2 mm, and some runs produced copies with bands that were 6mm wide.  The probable cause was either i1 or i2 PWB, or maybe both. After reseating the two PWB’s, dC310 was exercised with no fault code—indicating the PW’s were probably just peachy.

With the possibility that one of the two, or both, I-PWB’s were bad, a decision was made to swap them with a machine that was properly working.  Problem here is you can’t simply swap them like a light bulb; there is a simple install procedure that has to be followed to ensure that the Docutech knows the PWBs were changed.  The install procedure is as follows:

--Enter CTM Diagnostics

--Select test, select start and then wait for the test to complete. It takes about 5 minutes to complete the Boot test

--When the “Boot Test” is complete select “Boot”

--Enter “Diagnostics” and “Controller,” select dC310, select start

--Enter “Diagnostics” and “Controller dC302,” and do the disk confidence test.

So, with the new PWBs installed, the problem was still there.

When I received the call for help, my first question to the technician was: Is the copy quality problem visible from both the scanner (controller) and the Docutech (house) memory?  That was an interesting situation because the copies from within the Docutech dC606 program produced excellent copies that did not display any copy quality distortions. DC-951 was run with no noticeable distortions, as were the other in-house test patterns.  However, any copies from the scanner glass displayed the background lines as well as any test patterns in the controller dC-106. 

In desperation, the technician swapped out the Controller with another Docutech NP-135 printer, only to discover that it did not fix the problem. After eight hours of swapping parts (keeping your fingers crossed) and waiting for the DT to boot up to operating screens (holding your breath) the technician was at his wits’ end and needed some help! He was seriously considering going next door to the fire house and borrowing a fire axe to make the square peg fit into the round hole. The last item to be considered for replacement was the Printer Interface cable (PL9-A12, Xerox part number 152K33702).

To the best of my knowledge, in my career as a Xerox technician I have never replaced a Printer Interface Cable. However, there are a few RAPs in the service manual that actually lead you to replacing that cable for one or two intermittent problems, but none for copy quality issues. It is conceivable that the cable could be damaged by people stepping on it and damaging a wire. Or worse yet, a delivery person with a hand truck with 5 cases of paper plowing over the cable with six or seven loads of new paper. (And then there is that guy with the fire axe.)

Danny from the Midwest writes: “I was experiencing an ongoing problem in the finisher of a Xerox 5390 copier.  The symptoms were as follows: after a copy run to the finisher, the stacker door would rise to its upper limit and the stacker would start to deliver its payload of copies. When the stacker would be out of the finisher by about two (2) inches it would declare a finisher fault 12-217 and shut down.  The appropriate RAP was used in troubleshooting this problem and it was discovered that everything worked in diagnostics. The final resolution was: When the door would go up, the stacker safety door switch would get caught on the bottom of the door ramp and would not de-activate, hence the 13-217 fault code. The stacker safety door switch was adjusted and the problem was resolved.”

A technician from the New York City area had an ongoing problem with a C16-376 Printer Power system fault code. This system fault indicates the controller has sensed a printer power failure, or it could be a fault when the controller thinks the printer power state is not correct. This problem had been an ongoing system failure for about a week. The C16-376 RAP was followed to its conclusion and various parts that may have been defective were swapped out.  What made this problem seem a little elusive was that in the initial actions, we are asked to check the ELCI/RCD Breaker: Was it tripped? The problem was intermittent and sometimes the circuit breaker would trip and sometimes it would not. I guess it depended on how it felt. This RAP also leads you to other RAPs that are related to this system fault.

After a goodly amount of time troubleshooting and discovering that everything in the circuit checks and you run out of things to change or repair, try to focus on the Fuser Roll Thermistor assembly (PL3-D2). This system fault was the direct result of a bad thermistor where the plastic coating was badly worn (or missing) on the sensor assembly itself. When the thermistor assembly was replaced the problem went away.

Up-date on P06-250/251 system fault code.  If you are experiencing these intermittent fault codes and you have thoroughly eliminated all noise sources, try the following: Remove the processor electrical module rear cover assembly (PL1-C3), and just below the MIM cooling fan (PL1-C8) you will see the two cooling fans on the Backplane card cage. If one fan becomes useless, the temperature will rise and the heat will cause some weird things to happen—one of which is the PO6-250/251 system fault shut down. Both fans should be replaced at the same time (PL5-C2, Xerox part number 127P2096). The theory here is that if one fan fails, the other fan will probably fail soon thereafter.

If any tech has an ongoing problem on any Xerox 5090 or Docutech family copiers and would like some assistance with it, please feel free to contact me or e-mail us.  Or if you would like to contribute a resolution to a problem that the RAPs do not fix, please do not hesitate to share that information with the field. I’m sure there are many independent technicians out here that would appreciate the information.

If you have information that you would like to share with the field, please feel free to submit your ideas to VillageCopierNY@aol.com and I will place your suggestion or fix in the next issue of ENX. From what I hear in the field, it seems that many ex-Xerox technicians miss the field engineering team in Rochester, N.Y. Somehow it was always reassuring to hear a voice on the other end of the phone and a field engineer making a suggestion for a fix on your problem