|HP97 Card Reader working smoothly...|
Message #6 Posted by Vieira, Luiz C. (Brazil) on 2 Aug 2005, 9:24 a.m.,
in response to message #1 by Vieira, Luiz C. (Brazil)
first of all, thanks to all of you that either added valid suggestions to this subject or at least wish to help somehow and were not able to. Also, thanks to all of those who have already placed posts in the past about the HP67/97b reader; because I read many of those I agregated many new knowledge to my own about these masterpieces.
With no further ado, I opened the HP97 again and checked the excentric adjustment. After carefuly inserting a card, I tried to reduce the pressure by adjusting it and I noticed that it was almost in the lowest pressure adjustment. Based on the difficulty on inserting the card, I assumed that this unit has a new rubber puller, an O-ring perhaps (I did not open the card reader mechanics). So, by setting the lowest pressurew possible, I adjusted the contact blades again and now the cards smoothly 'walk' through the card readerīs head, either reading or writing. Even the noise from the motor + pulling gear has been reduced somehow.
About the contacts adjustment, I once read an adjustment procedure that worked for me. I'm not sure who posted it, so I'll not even try to wrongly refer to someone, so forgive me the one who posted it! The HP67/97 card reader has three contacts: one that senses a card has been inserted, another that senses the card 'position' so it can be read/written, and a third one that senses if the card is protected or not (read-olny card, cannot write on it). This adjustment procedure states something like to make sure the three contacts are closed wihtout a card inside the reader, then one should slowly recess (unscrew) each screw while measuring the related contact(ohmmeter) till it is opened. By finding the closer screw position where the contact is opened, recess it 1/4 of a turn (90 degrees). After doing that with the three contacts (and related screws), gently insert a card and check if the contacts close with it inside the reader. Remove it and confirm that they are opened. I'd also add that the small plastic actuators, the ones that actually push the contact blades when the card is inserted, should not offer too much resistence to the card insertion, and if that happens, maybe you should have a look at the contacts plate and check if it is not bent or twisted.
BTW, to those that have gone any further with these readers, I still have two questions: the 'normal', average current measured when motor is pulling a card and if there is any way to adjust the motor speed.
Wow! I wrote too much. Hope this helps as a partial guidance to those experiencing related problems with card readers. If anything I wrote here is not in accordance with either regular procedures or specific card reader adjustments, please, I'd thank for any corrections and/or additional info to this post in order to avoid dammage to calculators or related devices.
Best regards and thanks again.