LaserJet 4 prints black pages after new toner cartridge

[DaveGoTech]

We have an HP LJ 4M+ printer w/414K pages printed. Never a problem except for the normal maintenance such as cleaning and fuser replacement. We had a toner cartridge installed that developed a thin line across the printer page (drum problem?). We have lived with it because it wasn't too bad and most of our printed documents from this machine are for high volume internal use. Well, last week I decided to eliminate the problem by finally investing in a new cartridge (Verbatum). It came yesterday - I unpacked it, removed the shipping strip thing and installed it. Printed a self test page. The page is printed properly, but there is lots of varying degrees of heavy black banding across the page. Assuming it was a defective cartridge, I called the vendor and they said to return the cartridge and they will ship another. Meanwhile, I put the old cartridge back in since there is still toner left in it. It does the same thing! Looks like my printer is now broken!!! What happened? Is the new cartridge good - Did the new one burn something out? Any suggestions on what to look for to repair it? We do have a similar (LJ4) scrap printer to use for parts.

 

[edfair]

If this were a II or III the fix would be putting more pressure on the HV contact to the toner cartridge. I assume that the same solution applies. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[DaveGoTech]

OK - ED!
Based upon your suggestion, I removed the toner cartridge and inspected the HV contacts. 1 of them was bent over. I guess like inserting the new cartridge broke 1 of the plastic supporting studs for the contact. Fixed it with some glue and everything is now good again.