c3228 with low yellow drum life

[Herostrat]

We had problems with yellow drum units on this machines a while ago,after around 500 to 1500 yellow drum gets dots all over the surface,it's mechanical damage on surface,and slowly lines start to form.
We figured out that toner is making the damage since customers didn't use the RICOH toner,wherewer there was chineese yellow toner u can bet that yellow drum unit is damaged.
Now what troubles me is that this customer used the chineese toner brand and switched back on Ricoh after a while,I changed yellow drum unit (machine worked for around 3 months with Ricoh toners before that) and after about 700 pages drum is damaged again,yellow developer did around 40k.
Machine worked with chineese magenta toner yet magenta drum isn't damaged and I'm preety shure that yellow toner was out of the system before I changed yellow drum.
This makes me think that it may not be the toner causing damage,yet in the past when problems first apeared we started changing all we culd think of to figure out what's causing it and results were shown only after toner was replaced,when I say all we culd think of I mean power pack,drive,transfer belt,developer etc.My guess is that toner coagulates in some manner and reaches the surface of drum damaging it during the transfer on paper.
Anyone had similar issues on these machines,meybe we failed to see something here?

[slimslob]

Unless you purged the entire toner supply and then replaced the development unit, drum unit and toner pump you did not remove all contamination that resulted from the use of after market toner.

[Oze]

Unless you purged the entire toner supply and then replaced the development unit, drum unit and toner pump you did not remove all contamination that resulted from the use of after market toner.

Ya beat me to it Slim