The mystery of the psychotic printer

A techie becomes detective to crack the case of why the warehouse printer sporadically spits out illegible documents

Some years ago, I worked for a small tech company that supported various clients in North America. I was assigned to provide on-site client support at a midsize warehousing operation.

One day, I got a call from the foreman that a line printer located in the warehouse had inexplicably gone out of whack. It was skipping lines and printing lines on top of other lines, to the point that the document wasn't legible.

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I went to the warehouse to investigate, but couldn't find anything wrong. Later that day I got another call: same problem. Again, I couldn't find anything wrong. I was certain that it was related to hardware, because as a programmer I was intimate with the software driving the print process and saw no way that could be the issue.

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After a couple of days of the printer going out of whack, the warehouse foreman and I had a plan to catch the print problem "in the act." I told the foreman to watch the printer and let me know if he ever saw anything unusual, and to call me at my desk when the printer started acting up. When he'd call, I'd run out of my office and 100 yards across the lot to the warehouse, sprint up a couple of flights of stairs, and dash over to where the printer was located.

However, every time I got to the printer, it would be printing normally again. This went on for months, happening once or twice a day.

One day I happened to be standing near the printer for another issue. I noticed a warehouse worker walk up to it when a print job was in progress, look at it, shake his head, repeatedly press the Line Feed button, then walk away. I went closer to the printer and watched. About 15 seconds later, it started going crazy again.

I asked the warehouse foreman to page the worker, "James," who had just left. When James came in I asked him what he was doing at the printer. He said, "Oh, I'm speeding it up. Pushing that button makes it print faster."

The way their warehouse worked was that the ERP system would generate a document for each sales order as they were processed, and then send it to that warehouse line printer. After a warehouse worker filled an order, he signed the document, put it in a basket, then went to the printer to get his next one. Most of the time there would be another one already printed and sitting there, so there was no problem. But on occasion James would get there while a document was still printing, so he would "speed it up" by pushing the Line Feed button a few dozen times in quick succession -- no doubt trying to look busy because his boss, the warehouse foreman, was right there.

That's the reason we had such a difficult time figuring out the problem. It was very sporadic and only happened when James was the one (of about a dozen other warehouse workers) that got there if by chance it was in midprint. And since James would often walk away after pushing the button, another warehouse worker would sometimes come in and pull the document off the printer, see that it was illegible, and show the warehouse foreman, who then had to reprint the document.

Anyway, mystery solved.

I've been in the IT consulting business for almost 20 years, and have seen dozens of situations like this -- it seems like a lot of employees think only about the job at hand and go into drone mode techwise when they get to work. Our high-tech solution to this particular problem? We put a sign above the printer saying, "DO NOT TOUCH PRINTER WHILE IT IS PRINTING!!!"

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