HP Forum Archive 14

[ Return to Index | Top of Index ]

82143A Printer Message #1 Posted by Dane K. on 30 Aug 2004, 10:24 a.m. While cleaning my closet I came on my HP-41 outfit. After inserting new N cells it seems to work OK, except I had to replace the rollers in the card reader. I followed the directions on someone else's Web page. The printer works OK except that the feed seems a bit lame. It spaces up less than 1/2 the amount it should. I tried ripping out about one foot of paper, but this doesn't fix it. Is this because the roll of paper that was in it is about 20 years old? If it's not the paper can the feed mechanism be fixed? Thanks for any help!

Re: 82143A Printer Message #2 Posted by Vieira, Luiz C. (Brazil) on 30 Aug 2004, 3:17 p.m., in response to message #1 by Dane K. Hi, Dane; I found my 82143A almost the same way as yours after some years without activities. What caused the paper not to advance accordingly in my unit was the two rubber rolls that actually pull the paper "out". You can see them when there is no paper and when removing the small transparent protection where you can see the head moving while printing (I know, it is a silly description, but I found no words in my English knowledge base to describe it better... Sorry!). The "pulling rubbers" are at the both sides (edges?) of the axle that pulls the paper. I cleaned them both with a swab moistened with alcohol (had to press a little to remove some crusts), but I am not sure if the rubber is resistant to alcohol; maybe others will suggest better cleaning material. Hope you succeed. Cheers. Luiz (Brazil) Edited: 30 Aug 2004, 3:22 p.m.

Re: 82143A Printer Message #3 Posted by Dane K. on 30 Aug 2004, 5:14 p.m., in response to message #2 by Vieira, Luiz C. (Brazil) Luiz: It was difficult to access the rollers. I had to disassemble the printing unit. The printer now works OK. Obrigado! Dane http://www.marginalsoftware.com/Photographs/Wallpapers/wallpapers.htm (Picture of Rio)

Re: 82143A Printer Message #4 Posted by David Smith on 30 Aug 2004, 6:04 p.m., in response to message #3 by Dane K. Sometimes cleaning the rollers is only a temporary fix. The rubber develops a flat spot where is was stored in contact with the platen. One thing that helps quite a bit is to remove the feed cam assembly and use some medium sandpaper to true them up a bit and remove the crusty surface. I start by gently hand sanding the corners of the flat spot. Then I place the sandpaper on a hard flat surface and roll the assembly back and forth across it. You have to place some sideways pressure on the cam assembly to disengage the clutch gear on the end.

Re: 82143A Printer Message #5 Posted by Dane K. on 30 Aug 2004, 8:51 p.m., in response to message #4 by David Smith I only got as far as unscrewing the 3 screws that hold the print unit in place. It wasn't obvious how I would remove the rollers and the axle they're attached to. So I cleaned them in place and rotated them bit by bit. I didn't notice a flat spot. I guess it's inevitable that the rollers will disintegrate as on the HP-41 card reader. Has anyone been able to replace them? Thanks, Dane

Re: 82143A Printer Message #6 Posted by Randy Sloyer on 30 Aug 2004, 11:48 p.m., in response to message #5 by Dane K. If sanding them doesn't help and you get really desperate, you can take the path of no return and cut all the old urethane off. Only recomended if it is really full of nasty, deep flat spots. Once commited and the old stuff is cleaned off, fashion a somewhat similar roller from a slice of 5/16 od x 3/16 id vinyl tubing. Slip the ring over the axle. It will fit snuggly and not move. The od will be slightly larger so the spacing between the lines will be a bit longer but hey - it least it will advance. Suspecting it would work better, I've looked for silicone tubing but I could only find 100' lengths. The vinyl works well enough for me and it cost less than a buck in my local Home Depot.

Re: 82143A Printer Message #7 Posted by David Smith on 31 Aug 2004, 11:48 a.m., in response to message #5 by Dane K. Removing the feed cam is a real chore. You have to remove the print head and the guide rails, etc. The HP97 printer hardware is very similar and is well documented in the service manual available on the HPMUSEUM disks.

Re: 82143A Printer Message #8 Posted by Dane K. on 1 Sept 2004, 12:41 a.m., in response to message #7 by David Smith >Removing the feed cam is a real chore. Note that I replaced the roller on the card reader. That was one of the most fiendish repairs that I've ever done. The reader must have been designed by a sadist dwarf.

Re: 82143A Printer Message #9 Posted by David Smith on 1 Sept 2004, 11:28 a.m., in response to message #8 by Dane K. I have found reader repairs to be fairly painless except when those gold leaf springs in the 65/67/97 need adjusting. Then there are those little balls and rollers that like to go through the transdimensional hose-hole (one exists in every clothes dryer also).

Re: 82143A Printer Message #10 Posted by Dane K. on 1 Sept 2004, 10:40 p.m., in response to message #9 by David Smith The real bitch was the final assembly where the 2 halves are snapped together with all those parts hanging. One false move and one or more parts fall out. The 2 halves also kept jamming, preventing closure. Then there's the final matter of having those tiny screw hole lining up. That took me several tries and about 45 min.

Re: 82143A Printer Message #11 Posted by David Smith on 2 Sept 2004, 6:15 p.m., in response to message #10 by Dane K. After you have done it once or twice it gets much easier. I tend to put in the latch on one side, hold the case shut there. Slip in the other latch. Make sure the insulated sping goes on the side with the gold contact fingers. Insert the screws, then snap in the little front cover piece. One problem to watch out for is the springs that won't stay in the latch. A drop of superglue takes care of that.

Re: 82143A Printer Message #12 Posted by Tony Duell on 4 Sept 2004, 4:33 p.m., in response to message #8 by Dane K. I don't understand all this fuss about card reader repairs. I've never had any problems putting them back together, and even setting the leaf contacts in the 67/97 isn't that bad -- I did have one '97 from hell' that wouldn't set up properly until I'd completely stripped it and really cleaned the parts, but that's the exception. And the parts are quite large compared to some things I work on...

Re: 82143A Printer Message #13 Posted by Wayne Brown on 7 Sept 2004, 4:40 p.m., in response to message #12 by Tony Duell Quote: I don't understand all this fuss about card reader repairs. Neither do I. Even as klutz-fingered as I am, I managed to fix the "gummy-wheel problem" on my son's 82104A without too much difficulty. That was before I got my new glasses, too, so my wife had to talk me through a couple of spots where I couldn't see the innards of the reader clearly enough to tell what my fingers were doing. :-) If I can fix a card reader, anybody can!

Re: 82143A Printer Message #14 Posted by Tony Duell on 4 Sept 2004, 4:31 p.m., in response to message #7 by David Smith In my experience, the 82143 is significantly harder to repair than the 97 (Topcat) printer. Parts that are held in with E-clips in the latter are glued in place in the former. I don't like having to strip down an 82143 (or 82162, which can be even worse). Note that there are 2 versions (at least) of the 82143, and the mechanisms are not interchangeable between them (the older one has a reflective optoswitch screwed to the side of the mechanism, and a redd switch for the home sensor, the newer one has 2 optical sensors on the main PCB, like every 82162 I've worked on). The second version is a lot harder to work on!

Re: 82143A Printer Message #15 Posted by Vieira, Luiz C. (Brazil) on 30 Aug 2004, 11:58 p.m., in response to message #3 by Dane K. Hi, Dane; thanks for your kindness. It is a wonderfull site... I got my Electrical Engineering graduation in Petrópolis, about 60 Km from Rio (up in the hills...), and I guess this picture was taken close to there. I remember seeing Rio almost like this. About the rollers: my 82143A is dated 1981 (Serial # 2141Sxxxx) and I know the rollers have a small spot each. I was sure it would happen, as David Smith mentions, because it rest in the same position for a long time. Also, after using it a little, the paper seem to flow better. I am also sure they may desintegrate some time, but I guess that because the card reader rollers pull the cards through the magnetic sensitive surface, they have a different chemical composition. The printer rollers seem to be more resistent, and I almost all the time hear about gummy whells in card readers and desintegrated gears in printes (Topcat units), but I don't remember reading about someone in the need for changing printer rollers. What doesn't mean it didn't happen, right? I'd rather taking care of them as David mentions. (thanks, David) I'm glad your printer is better, now. Best regards. Luiz (Brazil) Edited: 31 Aug 2004, 2:52 a.m.

[ Return to Index | Top of Index ]

Go back to the main exhibit hall