Hp41 Card reader with Translation capability

[jftman]

I did a gummy on the Hp41 card reader. All I get is card error.
Not knowing if the standard and games pacs for the HP67 require special setup to use.
I read the reader manual references to SIZE and user switch stuff.
I tried it with the 41c, cv, and cx with same card error, then card………

I opened the unit to clean the leaf contacts, now the cards do not activate the motor.

My question is how do these leaf switches function? I know with the HP67 where to check with an OHM meter, and get how the balls move the leafs when a card passes through. I don’t get this HP41 setup!

Are the leafs supposed to sit touching the board above bcuz the bends are definitely pressing them both up. Can someOne provide a pic of a properly adjusted leaf spring and some instructions for proper operation?

[AndiGer]

Somewhere in the old forum is a picture of the leaf spring I can’t find adhoc.
Try search google restricted to site:hpmuseum.org
Here you can find pictures embedded that still work:
https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=165472

Andi

[jftman]

Needing information on the states of contact, open and closed why and how.
They obviously flex somehow and have an initial orientation.

This is an old forum pic only to show the platform with the leaf switches.

[David Hayden]

(02-20-2024 07:57 PM)jftman Wrote:  Needing information on the states of contact, open and closed why and how.
They obviously flex somehow and have an initial orientation.

I think you have the orientation correct, based on the service manual copy from the museum files. However, looking at your picture, are you sure the small retainer on the left side of the spring closest to the three screws is positioned correctly? It looks like left end of that retainer is up over the plate that it rests on.

[David Hayden]

More details from page 3-4 of the service manual:

Quote:Replace defective switch contacts and actua-
tors on the support plate . Lift out the contact by
one end; the actuator will fall out of the plate.
Insert the flanged end of the new actuator into
the opening in the switch plate and seat the
actuator's hinge pins into the recesses. While
holding the actuator with your finger, insert the
forked end of the new switch contact into the
contact recess in the switch plate, and then
gently insert the other end into the actuator slot
by flexing the contact. Note that no contact is
installed in the recess nearest the three screws.

[jftman]

That pic is from an old post by someOne. Sorry I did not make that clear it was not my project pic.
These leafs are or are not supposed to contact the board traces above at all times during operation of card reading?

I noticed the rocker actuator at the pinch roller position has a little hook end.
Because the motor worked before and after the gummy job, but now isn’t turning on I must have done something during reassembly after opening up the top end to clean the switches and the reader head.

When I was cleaning the leafs my q tip got snagged and one of the prongs got bent up a-lot. I wish to find out if these are in proper initial position being up really high and smashed down by the board. I can’t find how they travel with inserting a card to either touch or move off the traces.

There is no prior kniwledge that a previous owner messed with them.
This is why the proper orientation is where I would like to start with, and of course make adjustments with the help of a multimeter if so I would be interested in that test point practice in terms of which pins are involved for checking continuity.

[AndiGer]

Look into the old forum link I gave above.
The linked picture titled "The Printed Circuit, loose (w/text)" shows the PCB - front and back.
There once was the picture by Ignazio where you now only see the "Sorry ...".
I attach the pictue I once downloaded and saved.

The contacts numbered from left to right 1 to 5 resp. you can see that the leafspring for the motor closes contact 4 to 5 when a card is inserted as the leaf spring jumps up. The same is true for contacts 2 and 3 for read/write of the card whereas contact 1 is connected to contact 2 by a photo diode that detects clipped corner or not for write protect.

It is not easy to bend the springs to do their job as desired. You can nearly only see from the side if you look between the PCB and the frame when the PCB is mounted (or pressed down by your fingers maybe will work but you can hardly see the springs then) they spring up to close the contact when a card is inserted. But you can measure the resistance being zero at the mentioned contacts with a DMM.
If you bend the wrong way the springs give permanent contact and so the motor will run always. Or for the other fork the read/write contact is always closed and the reader will not work.

Andi

EDIT: Forgot to mention the picture in the second to last post ... as it shouldn't look like
EDIT 2: If you bridge contact 4 to 5 the motor should run as you bypass the spring

[AndiGer]

Did you get the service manual?
https://literature.hpcalc.org/items/396

[jftman]

Ok. I can jump back in with renewed intel. ThankYou Sir!
I surmise that the real contact during operation is made by the middle area jumping up and returning low?
Not those bent up enders, since they are always pressing against the board and their design is for both electrical and adding flex pressure so the middle area bows?

[AndiGer]

That‘s correct, you got it :-)