I have replaced a yellow cartridge and the colours

If this is a remanufactured cartridge, and its the yellow (new cartridge) that has gone weak, this could be caused by a missing idler gear.

I do the QC checks on a lot of these cartridges and have seen the occasional missing gear. It can happen sometimes.

The cartridge could have tested OK at manufacture, but then deteriorated in use

First, check the end of the cartridge with the white plastic 'end cap'. This is held on by a single screw (don't loose it, or the spring that pulls the two halves of the cartridge together).




Having removed the end cap being careful not to damage it, if the small idler gear is present, it will look like the following picture.



I have replaced a yellow cartridge and the colours - bc024db.pngmg src="/uploads/images/bc024db.png" alt="bc024db.png" class="h_mi" />
If the small idler gear is missing, this WILL cause rapid deterioration of print quality, certainly within 50 pages and I would have expected to see deterioration within less than 30.

The other side of the cartridge is more difficult to remove, and there are therr idler gears at that end, any 1 of them if missing will cause deterioration of print quality, though I would expect more than 50 pages before it would show.

Regardless, if the cartridge is new OEM, or new remanufactured, it should have some sort of warranty, so talk to your supplier.