hp Color Laserjet 4500 drum life reset

[Andy Cuffe]

I own an old hp color Laserjet 4550 that's been giving me the "drum
life low" warning for ages. This morning it finally changed to "drum
life out" and stopped printing in the middle of a very important (and
long) print job. Once it's out, there's no way to continue even if
the print quality is fine.

After finding nothing on Google about resetting the drum counter, I
decided to dig into the drum. The drum keeps track of the pages on a
93C46 serial EEPROM mounted behind the 8 pin connector on the left
side of the drum. I got to this EEPROM and lifted the clock pin (pin
2) and reinstalled it. I was pleasantly surprised to find that the
printer calibrated and finished printing my document fine. It now
displays "drum error, replace kit", but it still prints. I guess it's
set to continue printing if the EEPROM fails.

I don't know how long this will work for, but it's working great so
far. This will probably work for similar hp printers like the CLJ
4500.

 

[William R. Walsh]

Hi!

I don't know how long this will work for, but it's working great so
far. This will probably work for similar hp printers like the CLJ
4500.

I'm going to try on an HP Color LaserJet 2500n when its drum comes to the
end.

I don't know why, but I think HP marks these supplies as being "out" (for
both the toner and drum) before they truly are. I've never had the print
actually start to deteriorate from any of the four toners or drum when they
finally ran "out".

Since most of the work coming out of this printer is just draft quality
stuff, and subject to further revision, it does not have to look great at
all.

Thanks for the info!

William

 

[Andy Cuffe]

Hi!


I'm going to try on an HP Color LaserJet 2500n when its drum comes to the
end.

I don't know why, but I think HP marks these supplies as being "out" (for
both the toner and drum) before they truly are. I've never had the print
actually start to deteriorate from any of the four toners or drum when they
finally ran "out".

Since most of the work coming out of this printer is just draft quality
stuff, and subject to further revision, it does not have to look great at
all.

Thanks for the info!

William

After doing more printing it seems that there is a grace period of
about 100 pages after it loses communication with the EEPROM. Opening
and closing the front access door, or power cycling the printer resets
it for another 100 pages. Obviously not good for an office, but fine
for home use. I rarely print more than a dozen pages at a time.

Someone should examine the contents of the EEPROM. I wonder if a
blank one would work? I noticed someone selling replacement EEPROMs
on ebay.

 

[Michael Kennedy]

Good info!

- Mike