SR-52 card reader wheel

[albertofenini]

Hi Klaus, hi everyone

you must consider that these are not working units, and the test had the only purpose
to verify if the size and the grip of the tubing were compatible, which it looks to be case,
grips is pretty good, while the wheel appear to be a little eccentric which may be a cause
for not reading or writing well in a future working unit

consider that since these are not working units we powered the motor directly with an external 3V
battery pack, and that's why it runs probably faster and doesn't stop when the card is read

it must be said that at the beginning both motors were very slow but a drop of WD-40 in
the back, you can access the rotor removing the plastic cover from the back of the motor
has helped a lot both to reduce the noise and to improve the speed, still remember these
two motors are not calculator controlled, so I presume in real working scenario they may
run at lower speed

we have a little experience on the HP-65 and HP-67 card readers and we presume that
the working method here is probably more or less the same, so I'm expecting that also
here the motor speed is hardware controlled and that the springs in the card reader together
with the optical sensor will stop the engine when necessary

differently from HP-65, HP67 and TI-59 I understand that here the start of the engine
is not due to the insertion of the card but rather to the command 2nd read

we also need to improve (a lot) the way we cut the tubing, with HP models we use o-rings
but the capstan mechanical is totally different, will do more test today and we will probably
start working on a functional unit, just to see what happens

Any idea, especially on how to cut the tube, is very much appreciated!!!

take care !!