Archived from groups: comp.periphs.printers (
More info?)
On Thu, 04 Aug 2005 02:48:53 GMT, Dewaine Chan <"dchanNOSPAM"@NOSPAM
PLZZZnc.rr.com> wrote:
>Have you tested it with a different Toner cartridge??
Yes, almost the same. But it wasn't a new one so that's not
definitive.
I have found if I leave the printer on that after a few black/very
dark pages it gets back to almost perfect.
>
>Dewaine
>
>Tony wrote:
>
>> Alan <none@none.com> wrote:
>> >On Tue, 02 Aug 2005 09:10:23 -0000, Tony <> wrote:
>> >
>> >>Alan <none@none.com> wrote:
>> >>>On Tue, 02 Aug 2005 05:29:25 -0000, Tony <> wrote:
>> >>>
>> >>>>Alan <none@none.com> wrote:
>> >>>>>Recently my HP LJ4 has been printing pages almost 100% black. (The
>> >>>>>text is discernible with a lighter outline). The toner is all set,
>> >>>>>not loose.
>> >>>>>If I keep printing it usually improves, after one or two dark pages
>> >>>>>then it's fine. Today it's up to three black pages and little
>> >>>>>improvement.
>> >
>> >>I have to say that usually when the DC Controller fails completely then the
>> >>output is totally and always black, maybe it is slowly dying. The problem is
>> >>that your options are limited.
>> >>If the Laser fails then normally the output will have no print at all
>> >
>> >So I'm hoping that it isn't the power supply; from what I can
>> >understand from the manual, if the DC controller dies a whole lot of
>> >systems fail. Also, the fact that after several prints the quality is
>> >good doesn't seem consistent with that.
>> >
>> >I tried with another toner cart; this also printed very dark at first
>> >and then improved; though not as bad as the original. Can't
>> >definitively say it's not the cart as it's not factory fresh (an
>> >opened, almost empty, one I'd stashed away months ago).
>> >
>> >Is there a way to directly test the DC controller?
>> >
>> >Around here it's not easy to find used lasers of any quality, and
>> >transport is a problem, I have to hand carry a long way, so replacing
>> >is not an easy option.
>>
>> Not sure what to suggest, best way to confirm the cause is to swap parts from
>> another known good printer. Obviously that is difficult in this case.
>> You can eliminate the formatter by doing an engine test - as follows
>> Open the multipurpose tray, look inside and up to the right and you will see a
>> small button - pressing this should produce a page of black lines, they should
>> be sharp and clear. If this "consistently" works OK then the formatter is
>> faulty (very unlikely with the symptoms you have described).
>> If you are sure that the Toner cartridge is not the problem (again, very
>> unlikely that it would fail in this manner) then you have only two likely
>> causes -
>> 1. DC Controller
>> 2. High Voltage Power supply
>>
>> DC controller failure does not always produce other symptoms and the symptoms
>> it does produce can gradually appear (like any electronic failure).
>> As suggested previously it may be worth making sure that the internal
>> connectors are making good contact, remove the top cover and unplug/reconnect
>> the connectors you can see.
>> Tony