|
If you have signs of gummy substances on your cards,
after running them through the reader, the drive wheel may need to be replaced.
Other signs are irratic card movement, no movement, slow movement or
errors. |
|
The first thing you must do is to remove the case
back. This is not difficult but there are some precautions you must be aware
of. 1) Do not pry, from the sides or top, to remove the top 2 screw hole
plugs. 2) Be careful in lifting the label corners. 3) The feet, at the bottom,
do not come off. Just lift outside edges. |
|
Here is what the gummy wheel typically looks like.
|
|
Remove the 6 screws shown. You can lift the motor
drive circuit board where it connects to the main circuit board. This allows
you to remove the main PCB and easier access to the upper right screw, which
is under the circuit board. |
|
After you remove these 6 screws, the interior electronics
and boards can simply flip out to the right as shown. Be careful, the power
switch and program switch contacts sometimes stick to the keyboard PCB. Remove
these and set aside so they don't get lost. |
|
Slide the top half (part with keys) off to the side
until reassembly is needed. You may decide that you wish to clean keys, etc.
Make sure you know where they go before you remove them (get a photo). The
keyboard matrix can now simply be unfolded to the left as shown. |
|
Remove only the 5 screws
shown in the photo. DO NOT touch the silver colored screws that secure the
switch contacts to the board. |
|
This is the last screw holding the card reader together.
After you remove this screw, be careful not to pick things up. If you do,
you may lose the small nylon balls that operate the switches. Almost everyone
has lost one, at least once. You've been warned.
You may also remove the gold contacts in the charger connector. |
|
Now, simply lift card reader half, with the card
head, and flip it to the left. You should locate the 4 nylon balls, the pinch
roller and the two leaf springs. These have legs of their own and want to
hide from you. Find them and secure them before you go any further |
|
It should be obvious what needs to be removed. Just
look for goo. Remove the drive wheel by pulling out the slotted drive shaft,
indicated in the photo. You can't actually see it in the photo. The yellow
line points to it's location. Once you get this far, you'll easily be able
to see it. |
|
Now you can see why your card reader may not pull
card through the reader. Carefully clean off all the goo. You may also want
to check and see if any got into the hole in the center of the wheel. This
can cause slow motor if you forget to clean it out. |
|
I use pink silicone fuel tubing that I get at a local
model shop. It's outside diameter is just about perfect and the inside diameter
is slightly smaller than the outside diameter of the drive shaft. When you
buy this material, check for concentricity of the hole to the outside diameter.
If it's not concentric, you may get a variable speed when through. |
|
Trim the silicone tubing to fit flush to the edge
of the drive wheel. You don't want to leave tubing extending beyond the shaft
hole or it might rub against the side of the card reader housing and cause
slow motor. I don't use any glue. The fit is tight because of the size of
the tubing. |
|
Carefully clean all the interior parts of goo or
other residue. Don't forget to clean the pinch roller slot. Sometimes goo
get inside the two small depressions where the pinch roller sits. Install
all 4 nylon balls, the pinch roller and the 2 leaf springs. You can also
install the gold charger contacts, at this time. |
|
Make sure that none of the wires are in the area
that the card reader goes. Now, carefully, flip the card reader back into
position. It takes a small pressure to the left. If you do this right, it
will drop right back into place. |
|
Before you lift anything off the table, make sure
you put this first screw back into it's hole. This screw is the one screw
that allows you to pick this up. Failure to do so, may result in those little
balls taking wing. You've been warned
again. |
|
Now that the initial card reader screw is in place
(see previous step), you may flip the keyboard half
open and reinstall the 5 screws that hold the card reader together. Make
sure that these 5 screws are all the way in. Sizes of screws vary and if
the heads extend above the board, they will short out on the keyboard
circuits. |
|
Install the main PCB. Plug the motor drive board,
into the main PCB. Install the "power" and "pgrm" switches and contacts.
I apply a fresh coat of silicone grease to contacts. Then, carefully, place
the keyboard and card reader into the calculator case. Secure it into place
with the six screws. |