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Full Version: Re; Hp-67 r/w head height adj.
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Am repairing my hp-67 card reader and made the mistake of removing the magnetic card reader head from the plastic frame assembly. now, when a card goes through, it always reads error. does anyone know how to adjust the height of the head? i think there are two nylon balls beneath it. thanks, jeff brown

Oooh... big mistake. The heads were glued in at the factory and were never meant to be removed. The only way I know to set the height is to place a card in the mechanism and let the head rest on the card. The head must touch the card but not be so tight as to impede its movement. One problem is getting the head square to the card. If it is slanted then you can get read/write problems. I had a reader that with a loose head and it took quite a bit of playing around to set things right, but it can be done.

The nylon balls are used as part of the card detect/head switches. As the card slides over the balls they press on the gold leaf springs that then make contact with pads on the back of the keyboard. The three main switches are card edge detect (motor on), write protect detect, and head enable (a delayed version of card edge detect). There is a fourth switch that I don't beleive is used for anything.

dave, thanks for your suggestion. i thought i had it a couple of times, but by the time i glued it and retried it, it came up with errors again. am using a hot glue gun which holds fairly tightly but can be remved with an exacto knife. the latest attempt was to disassemble the card reading assembly, put a card in just the top part and try to let the head drop into position, where i then glued it. result was that when the part that holds the head was reinstalled on the rest of the board, too tight a fit ensued and had to start over. maybe your suggestion would be to put a card partly thru the card reader while installed and let the head just rest on the card, and then glue in place. am i getting it right? any idea if there is a factory manual that describes overhaul procedures? thanks for keeping up with this.

Yes, that's what I did on mine (it was about 8 years ago so things have grown a bit fuzzy). The only service manual for a reader based machine that I have seen is the HP-97 manual on the HPMUSEUM CDROMs. I dont think the head is considered a replaceable part.