Damaged HP 9810A

[Tony Duell]

(05-02-2014 11:17 AM)douze-bis Wrote:  Now I guess the next steps are:

1- The magnetic card drive
The drive looks a bit dirty, and the "capstan wheels" have disintegrated of old age (see the attached picture).
Any advice how to deal with it ?

I see that Kattie has already replied.

My method is a lot more work, but I think it should be more reliable. I dismantle the reader, and get the old hub off the spindle. I then turn a new hub from brass (Outside diameter 7/8") with a couple of grooves for 1" diameter O-rings. I fix this hub on with a grub screw.

There are some photos in my flickr account (tony_duell). The album is called 'HP9820 Card Reader', but it's the same unit.

(05-02-2014 11:17 AM)douze-bis Wrote:  2- The fan
The fan seems to be tired and requires "help" on each power up or it won't move. Then it is noisy.
Any idea where to get a spare, or how to fix it ?

This is a 120V AC fan, run off the primary winding of the mains transformer. They are
still available, but you might not need to replace it. All my HP9800 machines still have the original fans.

Remove the rear panel from the machine. To do this, first take out the PSU boards, then unscrew the 2 edge connectors that are fixed to the case (these carry the AC outputs from the transformer). Loosen the nut each side near the top, you need an 11/32" spanner for this which is not easy to find (in the UK). Then take out the 3 screws on the bottom and pull the panel off, feeding the mains switch cable through the chassis.

On the face of the fan are 4 Phillips screws which hold the fan housing toghether. Take these out and lift off the top complete with the motor and blades. The motor is fixed with 2 screws under the label, feel for these with a screwdriver and take them out. Then you can see a circlip on the end of the spindle. Take this off, and it all comes apart. Clean the parts and put some light oil (I use clock oil) on the spindle and bearings.

Again there is a photo in my flickr account, in the 'HP9820' album.

(05-02-2014 11:17 AM)douze-bis Wrote:  3- The bezel
The bezel is broken in several places.
Any advice on the best way to glue it back together ?

These bezels get very brittle with age, I am afraid.

To mend them you need a solvent that will disolve the plastic. I use dichloromethane (methylene chloride) which is sold in the UK as 'plastic weld'. What you do is put the bits together and run a brush dipped in the solvent along the cracks. This will soften the plastic and the parts will weld together.

Now get a piece of cotton fabric and cut a bit to fit over the back of the damaged area. Put it on and 'paint' it with the solvent. When the plastic has softened, force the fabric into the plastic. This will strengthen the repair. The bezel will still be fragile of course.

The screws that hold the keyboard to the bezel were locked with 'threadlock' adhesive. Unless you plan on shipping your machine around a lot, I feel it's best to get rid of this to reduce the torque in fitting and removing the screws. I cleaned mine up with a suitable tap and die (4-40 UNC I think). They now go in very easily.