HP Laserjet 6P ghosting - Page 1
Forum section: electronics / repair

author: tocsa120ls
author_rank: Regular Contributor
timestamp: October 17, 2018, 09:42:04 pm
content: Hi ladies and gentlemen,my venerable 6P seems to have had enough. I've been looking to replace it with a newer Epson AL-M200 for a while now, as with every once in a while it would spit out a blank page with %12345 at the top (I chalked it up to the chinese Centronics/USB converter) but now it started to 'ghost' the prints. I opened up a NOS (yeah, they are around) 03A cartridge and replaced the whole toner/drum assy, but it is still doing it.Made two prints, the first one is the self-diag page, you can see the old demo page from the prev. print on it. Then I did a half-print, because I suspected the fuser unit, but the ghosting is happening at the drum.Pulled the PSU, completely shooting in the dark I replaced the two caps on the low voltage rails (the smaller one had bad ESR), checked the triac that controls the fuser (okay), and the little HV panel (all diodes are okay). No change. At least I didn't make it worse.So... I suspect the HV supply died that's supposed to clean the drum after it rolls the toner over the paper?Time for that EPSON or does anyone know a way to fix this?

author: helius
author_rank: Super Contributor
timestamp: October 17, 2018, 11:19:10 pm
content: Did you clean the corona wires? This is absolutely required maintenance on laser printers, in addition to changing the toner cartridge and fuser.

author: andy2000
author_rank: Frequent Contributor
timestamp: October 18, 2018, 02:40:37 am
content: How old is your new old stock toner cartridge? The rubber wiper blade doesn't last forever (particularly if it was stored in a hot environment). I've encountered several bad new old stock cartridges for my LJ 4 which produced dark, streaky prints like yours. Anything over 10 years old is suspect.

author: BradC
author_rank: Super Contributor
timestamp: October 18, 2018, 03:07:21 am
content: Quote from: andy2000 on October 18, 2018, 02:40:37 amI'll second this. I have the same wiper blade issue with all of my 96a carts for a 2200d. Having said that, in my case the wiper blade fault reproduces the ghosting for the page, but doesn't appear to bleed onto the next page as it appears the drum does an additional couple of cleaning rotations between pages.Have you checked the fuser? If the film is on its way out it may well be retaining toner, leading to both light prints and repetitions. I believe the fuser and drum in those machines are roughly similar diameters, which would lead to about the same repetition.A standard test is to set it up to print a page and pop open a cover when about half the page would be past the drum. Pull the cartridge and have a look at the paper. Is the ghosting on the paper before it gets to the fuser?Check this thread out also :https://www.eevblog.com/forum/repair/hp-laserjet-drum-problems/

author: tocsa120ls
author_rank: Regular Contributor
timestamp: October 18, 2018, 10:06:56 am
content: Going to pull the old drum assy apart and look for this wiper... yeah the NOS cartridge is also 10+ years old. Had no idea they break sitting in a sealed cardboard box, in a sealed black plastic bag with a desiccant pack(BTW, the 5/6P/MPs don't have corona "wires" to speak of, there are two spring loaded contacts from the main power board that poke the underside of the drum cartrdige - both squeaky clean, of course.)

author: xavier60
author_rank: Super Contributor
timestamp: October 18, 2018, 10:23:25 am
content: When the wiper blade is still good, the drum is very difficult to turn.

author: jmelson
author_rank: Super Contributor
timestamp: October 18, 2018, 10:44:49 pm
content: Quote from: andy2000 on October 18, 2018, 02:40:37 amYup, agree! Wiper blades seem to last only about 2 years if in the cartridge. You can get replacement wipers for a couple $ from fixyourownprinter and they get it working fine again. I have an LJ5, but the wiper problem looks very much like your scan.Jon

author: andy2000
author_rank: Frequent Contributor
timestamp: October 19, 2018, 03:41:29 pm
content: I didn't know you could buy replacement wipers. I'm going to order some so I can use the pile of NOS 98A cartridges I have. I'm glad I didn't throw them out!

author: tocsa120ls
author_rank: Regular Contributor
timestamp: October 20, 2018, 09:45:42 am
content: Motherf.....! (Sam Jackson voice) The wiper was as firm as a used tea bag.I didn't want to mess about it since the last recharge my home is several shades darker, I just bought a replacement cartridge.Excellent result. Thanks for all the tips! Now back to cleaning this old Tek 453A I've just bought