HP laserjet CM4540 MFP

[stobby2]

We tried to sort this issue last year with your guys help but unable to find the fault. Machine will print all colours apart from Black. We have tried two new toners but still no joy. When a test print is sent there is a light dusting of black toner on the drum but no image and nothing on the paper. Not even a slight image but as mentioned colours are perfect. Seems a shame to scrap it as only done 15K since new and has got full HP original toners installed. Any ideas would be appreciated

[Wild Bill]

When you print a config page what happens?

[stobby2]

We tried to sort this issue last year with your guys help but unable to find the fault. Machine will print all colours apart from Black. We have tried two new toners but still no joy. When a test print is sent there is a light dusting of black toner on the drum but no image and nothing on the paper. Not even a slight image but as mentioned colours are perfect. Seems a shame to scrap it as only done 15K since new and has got full HP original toners installed. Any ideas would be appreciated

Just prints blank white page

[Wild Bill]

My thought would be ITB

[Murv]

Might be a longshot, but I had a M477 doing exactly the same thing. Black wouldn't show up, even on the engine test. Turned out to be a mirror out of place in the laser housing. Cleaned it, popped it back into place completely, and boom. Like new.