If you've had a Pixma Pro printer for any length of time, you've probably experienced, or at least heard of, the B200 error problem. When this occurs, you can't print until you resolve the problem. There are different theories as to what causes the error; letting the printer sit idle too long is the most popular, but I've also run across unstable power supplies being reported as a cause. I don't recall the other theories, but I have another theory that I have not seen documented elsewhere. First, let's understand that the B200 is Canon's catch-all error code. If it's not one of the dozen or so specific errors that have their own codes, it gets dropped into the B200 bucket. That means that ALL of the theories may be correct. Canon, tellingly, do not offer an explanation for this, other than "well, that's what happens when you use cheap ink." But, I've had it happen with their ink, too, so... I've recently had it happen to my original Pro-100 again, and when the usual tricks didn't solve the problem, I took an unusual approach. I found someone selling a brand new Pro-100 without the ink cartridges, but with a factory-sealed, shiny new print head, for less than half of what a print head costs through normal channels. So, I bought it. Brought it home, set it up, put my old ink cartridges into the new print head, turned it on, and got the B200 error. To me, that eliminated any possibility that the print head was clogged with dry ink or that it had been frazzled by unstable power over time. What's left? The ink cartridges. Canon support will always suggest a new set of cartridges but, at $125 per set, that's not my favorite answer. They will also tell you that the B200 requires bringing the printer to a support center, but the nearest such center is in another state, 289 miles from where I live. I don't live in the middle of nowhere. I live in the 5th largest metropolitan area in the US. They have authorized centers in towns the size of my school district, but not one within reach of the 5 million people here. Options? I could order a new $125 set of Canon-brand cartridges. I could order a $30 set of off-brand cartridges. I could also, being a refiller, order empty cartridges and refill them from my stock of ink. And that's what led me to the possible solution I want to share; resetting the chips in the ink cartridges. If you've ever inserted one of these cartridges, you know they have computer chips on one end. This is how the printer can tell you when it's running low on a particular color of ink. And, usually, when it does so, you open up the printer, wait half a year (subjectively) for the print head to appear, and see which one(s) is/are blinking. In my case, I'd already seen the print head several times, and I knew that none of my cartridges were blinking. The printer had also not told me that any were low on ink. But they were. In fact, my yellow cartridge was almost dry, and should have been blinking, but it wasn't. Clearly a classic case of what we in the IT industry refer to as a machine that's confused. That's not supposed to be possible, but it happens. So, I refilled all my cartridges (always do all of them at the same time), re-set the chips, re-installed them, and watched as the printer figured out that "Oh, there isn't really a problem, after all." No more blinking alarm light flashing the dreaded B200 signal. Problem solved. Those of you who do not refill your cartridges are not going to have the chip resetter sitting around, because Canon doesn't provide them. They don't even want you to know they exist. But they do, and they are absolutely necessary if you're going to refill your cartridges (and you don't want to risk destroying the printer), so the people who sell bulk ink make them available. Resetting the chips "makes them aware" that they are now full again, so they will report their status correctly to the computer. The resetter is not cheap. The one from http://precisioncolors.com/PC42reset.html costs $48.99, all by itself. But, you can also get it as part of a complete refill kit for $88.98, which includes enough ink to refill each color cartridge many times. DO NOT PRINT AFTER RESETTING YOUR CARTRIDGES WITHOUT REFILLING THEM! If you do so, they will report that they're full when they're not and you run the risk of running them dry, which Canon says can damage the printer. However, it could be a useful diagnostic test, to determine if it's the cartridges causing the error. If resetting them makes the error go away, then you need to decide whether to refill them (and reset them, again), or buy new ones. Also, be aware that using reset cartridges probably voids your warranty, but this usually doesn't happen while the printer is under warranty.