[personal] Shaft encoder in HP2631B printer
hp-fix at xs4all.nl
Mon Jan 25 15:42:12 CST 2010
> -----Oorspronkelijk bericht-----
> Van: cctalk-bounces at classiccmp.org
> [mailto:cctalk-bounces at classiccmp.org] Namens Tony Duell
> Verzonden: maandag 25 januari 2010 20:27
> Aan: cctalk at classiccmp.org
> Onderwerp: Re: [personal] Shaft encoder in HP2631B printer
> > Sounds like it may be a HEDS or HEDL encoder as it's HP,
> any chance of
> > a photo or a p#.
> It has a number QEDS8997 on the end cover (the part that
> carries the LEDs). There may be a number on the other end of
> the housing, but I can't remove it to check, the screws
> holding it to the bearing plate are covered by the encoder
> disk that's emoxied to the eladscrew and which needs the
> special tools (according to HP) to remove/replace.
> I cna't easily provide a photo (no digital camera). If you've
> ever worked on HP9000/200 machines, it's similar to the
> encoder used on the twiddleknob on the keyboards of said
> machiens, but without he spindle/mounting bush.
> > > Anyway. Iv'e read the HP service manual (on
> > > and
> > Link to the manual ?
> The easiest way to get to it is to go to said site, then
> naviage through 'printers' 'impact' 'hp2531' 'product
> documentation'. You'll then see a serevice manaul (and a CE
> manual) for the 2630B series listed. I think the encoder i
> nthe 2531A is similar, the one in the 2631G is very different
> (and, alas, looks a lot more repairable from the manual).
> > We use HEDS an HEDL's all the time, no special tools.
> According to the manual, this encoder was supplied as 3
> separate parts.
> The housing, constianing the sensorts and with the cable
> fixed to it ; the encoder disk; and the end conver containing
> the LEDs.
> THey are fitted in that order, and removed in the reverse order.
> The hub of the encoder disk doesn't have a setscrew or
> similar. It is glued to the hend of the leadscrew with epoxy.
> One tool is used to remove the disk (it hocks round the hub,
> and a screw then applies pressure to the ned of the shaft to
> pull the disk off, breaking the epoxy bond. The other tool is
> used to bet the disk back on the spindile, it, again, fits
> round the hub and rests against the end of the housing, this
> getting the disk the right distance inside.
> What is not clear ffom the manual is wheter this procedure
> damages the disk, or whether you can refit the old one if you want to.
> My guessis that he other reply is correct, and that the LEDs
> are out. If that's the case, I may not need to remocve the
> encoder assembly. The end cover carrying the LEDs comes off
> anyway. The whould thing can be removed from the printer
> complete with leadscrew, bearing, and bearing cover plate.
> And after doing that it's possible to unclip the cover over
> the cable and get to the edge of the snensoor PCB. Maybe that
> will be enough.
The HP 9000/200 series knob encoder uses a small bulb, witch I replaced for
a white LED (3mm type).
I had to remodel the LED a bit to make it fit.
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