Laser Jet Pro M148dw has black dots on the right side

[debaire]

This is a brand new printer. I have had it less than a couple of weeks. It has the black dots on the right side in two places 2.5cm apart which is the tell-tale sign of some impediment on the drum or the cartridge. I have opened at looked at the drum and the ink cartridge and have tried to clean the areas rolling through to find some issue. I can't find anything and no matter how many times I do the Clean cycle and print it still shows up. 

I've had HP printers for years and this is the first time I've seen the drum and the cartridge split into two separate units. This is also the first time I've had a two-sided printer so that may be the case. Either way, the dots show up on both sides. 

This is a new printer! Please help.

[ALS-77]

I have never found the cleaning cycle to fix anything. It is most likely the drum cartridge, but it could be the toner or even fuser causing this. My approach to troubleshooting these problems, if not clearly evident, is to do a Stop Test.

This is where I start a single page print job, either from the computer or an internal printer test page, and open the access cover of the printer when the paper is about half way through the printer. Remove the cartridges and inspect them for the problem as well as inspect the paper. If the dots appear on the paper prior to reaching the fuser, then the problem is on the drum/toner cartridge. If only after the fuser, then the fuser is the problem. Be careful pulling out the paper so as to not damage any sensors. It's best to pull the paper out in the direction it is supposed to go and not pulling it backwards.

Checking the drum and toner will be easier to spot where the dots are coming from at this point too.

[debaire]

I did it and here is what I found.

The dots show up on the first half of the page where the item has been printed but not in the bottom half where it hasn't been printed yet. I'm assuming that means a toner/drum problem? My drum and toner come in two separate parts. What are the next steps in cleaning or trying to get rid of the anomaly? I've tried turning the drum and cleaning any obvious specks or dust spots. I'm not sure what to do with the toner part, however.

[debaire]

It appears that the second side of a two-sided print does not have spots. Does that give anyone a clue?

EDIT: JK, both sides present the problem.

[ALS-77]

Amazingly, I can't find a service manual on this printer (which I've never not been able), so I don't have a repetitive defects ruler to reference. My bet is on the drum cartridge, because of the distance between marks I think it's the charge roller, but it could be the toner cartridge just as easily. Since you couldn't find anything on either when inspecting them, the only remaining option is to replace one and see if it fixes the problem, by process of elimination at this point.

[debaire]

Thanks for your reply. Seeing how this is a brand new printer, should the replacement be covered?

And it's no wonder you can't find a manual on it. I think it may be an Asia-Pacific specific model. I bought it in Taiwan. The US-based HP customer support wouldn't help me because the model was not one that is sold in the US. I just wanted some basic troubleshooting ideas but they kept referring me to a Taiwanese customer service number even though I told them I'm not Taiwanese and I need help in English.

[ALS-77]

Interesting. Good to know about where you bought it. I found lots of tech articles on HP's tech site, but no manuals, which I still find odd, but could explain why. As for the replacement being covered, I would think it would be, depending on when you bought it, but you may have trouble since it was bought in Taiwan, HP may have some issues covering it. Try contacting HP warranty support and see what they can do.