Saturday, February 24, 2007

A Printing Mystery

The print on the left is a good print for my Epson R 800 printer.
The print on the right is what I was getting last month. You'll never guess why!

by Ctein

This post is 24-karat geeking.

My PC fried its motherboard. My service people, who built the system, are fabulous (Polywell, 1-800-676-6618). They dug into their stockroom and found a motherboard just one generation later than my 5+ year-old one. I didn't even have to update Windows 2000 or reactivate Adobe Photoshop, the configurations were so similar. All I needed were a couple of new drivers for support chips that had changed.

Then life got hinky. I tried printing print out a high-quality photo on my Epson R 800 printer. It should look like the left side of the illustration above. It looked like the right side! Long diagonal streaks of minus density that varied in a position from print to print.

Sure looked like a printer problem, but cleaning heads and replacing ink cartridges didn't make any difference. So I tried printing on an Epson R2400 and the same thing happened! OK, not a printer problem. Same thing printing from Picture Window; not a Photoshop problem. Disabled all the profiles associated with the printer and still got crap.

That left the printer drivers. I uninstalled every single Epson driver on my system, including the hidden ones that you can only get to in the device manager. Reinstalled the R800 driver. Still bad!

At wit's end, I send plaintive emails to the PC experts I know. Gradually they come to agree it has to be a hardware problem, because there's nothing else left. Scott Raun, after some head-scratching, says it feels to him like RAM that's stressed out and misbehaving.

Memtest32 says all the RAM is good, but I trust Scott. Any one of my three RAM modules is sufficient to run the system, so I pull all the RAM except Module 1. Reboot, launch Photoshop, and print. Finally, it prints fine!

I install just Module 2. The machine won't even boot! It hangs up before I even get a BIOS screen. Doesn't matter what memtest says; that RAM ain't normal. (Don't ask me why it "worked" when installed with other RAM but not by itself.) I bought new RAM, installed it with the other two good modules, and I haven't had a printing problem since.

What looked just like inking problems or a faulty driver wasn't. It took me a week to track this down. Here's hoping it will save someone else from wasting their time.

Posted by: CTEIN

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