I've noticed a few others have had the same issue but I couldn't find any that had actually fixed the problem.
I have two 7900's that make the same noise although at different places on the shaft. The shafts look fine without any visible wear. I've cleaned the shafts and tried light silicone oil, heavier 3-n-1 all the way up to Lithium grease with no luck. The noise is definitely the bearings because if I 'chase' the carriage, wiping lubricant on the shaft ahead of it, the squeak is quieter for a moment. Also, if I apply a slight amount of pressure on the carriage while it's printing, the noise disappears.
The bearing/bushings seem loose to me, though I have a 9900 with bushings that are just as loose but no squeaking out of that one. It looks like there's a high or hard spot on the bushing because you can see a noticeable area that wears off the lube after each pass if you wipe lube on it ahead of the carriage.
The carriage also makes a 'clunking' sound at the left end of the stroke when it returns to the right, which leads me to believe the bushings are overly worn and it's rocking on the shafts. I'm guessing the bushings have around .015 to 020" clearance, maybe more. .005" should be enough.
The printers have between 10,000 to 15,000 pages.
The carriage is supported by two 'Oilite' bushings of unfortunately non standard sizes. I can easily machine some up on my lathe but my concern is how to get them out without damaging the carriage.
Has anyone here attempted this? I guess I could buy new carriages for them at $340, but putting $10 worth of parts in them is more my style.
Thanks.
Lee Hagen
Delafield,WI
