HP Forum Archive 07

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9100A: mag card reader drive wheel replacement Message #1 Posted by Dave Brown (NZ) on 7 Mar 2002, 4:04 a.m. Bringing one of these marvellous machines back from the semi-dead. Has anyone experience of replacing the rubber drive wheel in this card reader? It has an aluminium boss with a soft(now nearly totally droooped off!) rubber compound 'tire'. If this topic is covered by any of the docs on the CDs then sorry for the bandwidth - not bought 'em yet!

Re: 9100A: mag card reader drive wheel replacement Message #2 Posted by Tony Duell (UK) on 7 Mar 2002, 2:49 p.m., in response to message #1 by Dave Brown (NZ) I've replaced the rollers in both my 9110Bs, which have a mechanically-similar reader. Be warned this is _by far_ the most difficult roller to replace. Forget HP documentation. The official HP repair is to replace the complete reader (with its associated PCB). Needless to say that's impossible now (even if you could afford it). The basicp pr: Remove the reader from the 9100. Take it totally to bits (remove the motor/roller assembly). Remove the old roller from the motor spindle. Don't try to prise it off, you'll bend the spindle. Remove it with a puller. A small 3-legged puller might fit, but I made a special tool from a block of metal. Then make a new roller. I found it best to make a new hub 7/8" in diameter with a 1/16" deep groove round it for an O-ring. Then fit a 1" OD, 3/4" ID O-ring. Yes, I know the original roller has a flat on one side, but this is not _essential_ for the reader to be useable. To fit the new roller, you need a pair of drifts in a bench vice. Don't trhy to tap it on, you'll damage the motor bearings. And you have to press it on by just the right distance After that, it' all becomes easy. Put the reader back together, put the reader back into the 9100. Needless to say you need a reasoanble workshop to do this. A small lathe is essential. A local model engineering club (The sort of place where people make small steam engines, etc) might be able to help.

Re: 9100A: mag card reader drive wheel replacement Message #3 Posted by Mike on 7 Mar 2002, 3:12 p.m., in response to message #2 by Tony Duell (UK) I deleted my other post because I was only speculating on the repair. Since you have done it, I defer to your post. But let me ask a question. On the 9810, these wheels turn fairly slow when comparred to cassette tapes, etc. Why can't one just break an o-ring and glue it in place. Since speed is not a real issue, wouldn't that work as well. I doubt that it would fly off after spinning. If that would work, it would save a lot of disassembly. Just curious.

Re: 9100A: mag card reader drive wheel replacement Message #4 Posted by Dave Brown (NZ) on 8 Mar 2002, 1:14 a.m., in response to message #2 by Tony Duell (UK) Thanks for the info Tony- I had considered a similar process but hoped there may have been a less drastic approach- I took the motor and drive wheel out some time back and was trying sliced off bits of hose etc to find one about the right diameter. But total replacement of the wheel assy is a better option as the right combination of rubber O ring and matching centre wheel can be made up. I suspect the neoprene material the O rings are made from these days is more squishy(now there's a good technical term!) than the stuff the original rubber ring was made from-- so the flat is not actually needed as the card should push past the O ring more easily than for the original stuff. Don't have a decent mechanical workshop here but ain't bro-in-laws wonderful!

Re: 9100A: mag card reader drive wheel replacement Message #5 Posted by David Smith on 8 Mar 2002, 5:06 p.m., in response to message #1 by Dave Brown (NZ) A company called "Projector Recorder Belt Company" (or something similar) sells an extensive line of square rubber drive wheels. They have them that are almost identical in size to the 9100 drive wheel (I replaced the drive wheel in my 9100 mark-sense card reader with one). They only cost a couple of bucks each. You can slice off a tangential piece from the edge to get the flat spot for the 9100 card insertion area. I will see if I still have the part number of the belt that I used. They also have some small belts that work fairly well in the 82143A printer... they are square, but do seem to work in the printer. Most standard "O" rings are too thick to clear the projections on the printer mechanism near the motor drive capstan.

Re: 9100A: mag card reader drive wheel replacement Message #6 Posted by Dave Brown on 8 Mar 2002, 8:37 p.m., in response to message #5 by David Smith Can you pse email me direct Dave Smith? If you have a working 9100 I may get you to check a few things for me at some stage in the future as well as take one or two relevant pix if you can? Tks.

Re: 9100A: mag card reader drive wheel replacement Message #7 Posted by David Smith on 11 Mar 2002, 6:19 p.m., in response to message #1 by Dave Brown (NZ) The replacement drive wheel that I have used is from the "Projector Recorder Belt Company". It is their part number ST1.014. They are 0.75 inch inside diameter, 1.014 inch outside diameter, .140 inches wide, square profile. They also have a ST1.016 that I suspect would work just as well if your supplier is out of stock on the ST1.014 The HP drive wheel has a 0.40 inch tangetial cut taken out of the bottom edge to provide clearance for the card to be inserted. On my 9100A there was no need for any complicated pullers, etc. to access the drive wheel. 1) Just take out the one screw that holds the motor. 2) Take out the two screws than retain the drive shaft bushings. Remove the bushings. 3) Note the orientation of the switch cam. The drive shaft may or may not have a flat side for the cam set screw. Mine did. Remove the cam that operates the microswitches (it has a set screw). 4) Lift out the motor/shaft/roller assembly. If you can find it, mark where the flat side of the drive roller was so that you can install the new drive roller in the same place. I suspect that you may not need the flat cut to the edge of the drive wheel. It makes inserting the card easier. Scrape off the old roller. 5) Glue the new one roller in. I use IC2000 Tire Cement. It is a rubbery superglue used by radio control car people to glue their tires on. I suspect that RTV silicone adhesive would work very well also. 6) Reverse the steps to put it all back together again.

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