My 450C started acting strange yesterday, showing black streaks. I replaced the black cartridge (which wasn't empty, but getting there) to no avail. Priming didn't help, and running the various test plots didn't seem to do much good. I fiddled with the trailing cable a bit, and that coincided (if not caused) a slight improvement. I then ran a plot of a drawing with wide black stripes, and that seemed to fix things. I got the plots I needed and shut it down.
This morning I tried to run some more plots, but the plotter would freeze about 1/8 of the way through, showing solid orange on the Cartridge, Data and Media lights. Pressing cancel (to display the subcode) showed solid orange Align and Media lights, which corresponds to a Y-Axis Shutdown. The service manual speaks of carriage binding, so I slid the carriage over and did notice a bind. Closer inspection revealed evidence of belt shredding. I ordered a new belt, and will have to wait until it arrives to resume plotting.
I last replaced the belt in March of 2006. I guess that's a reasonable lifespan for a plotter belt, so I'm not too unhappy with the situation. I ordered a new trailing cable as well, and will replace it while I have the unit apart just in case.
Also a good idea to clean the bar that the carriage rides on and re-oil it. HP has special oil for the carriage that works well but is a little on the expensive side.
I agree with Stephen that you probably need to clean and oil the rail that the carriage rides on. Instead of using the HP oil, I went to the bicycle shop and got a small bottle of TriFlow oil with teflon. It was very cheap and very good and I have used it on all my plotters and printers since then with no problems. If you really think the trailing cable is the problem, I would replace it at the same time, but I would try the rail cleaning and lubing first. Also, the black streaks can be caused by ink buildup on the bottom of the carriage or a spittoon that is full. Run a Q-tip under the carriage and see if there is ink under there. Also with the plotter off, slide the carriage to the left and take a flashlight and look inside the right side of the plotter where the carriage comes to rest to see if the spittoon is full. The spittoon has 4 rectangular openings and you should be able to see down into them if they are not full. Sometimes they are so full, that they are level with the top. It is a dirty job to clean it, but you can take a Q-tip and dig the ink out of each opening (they all lead into one single cavity) enough to make the plotter work again. But the best way to clean the spittoon is to remove it while the cover is off while replacing a belt or the trailing cable. I realize that if you have already replaced the belt once, that you probably already know all this.
Stockings (or strips of) make great cleaning cloths dragged back and forwards round the bar.
Not sure about a replacement for a warn belt but they do work as fan belts.
hijack/psa
I NEVER print color on my 450-C. The color ink would just eventually just dry out.
A few months ago, I took out the three colors and just left the black. The cartridge light blinks constantly, but it prints just fine. Actually, it seems faster.
This may be common knowledge, but it was news to my printer guy...
