HP-67 Card Reader became very touchy

[Alevin]

New update with the task of fitting the Hp-97 card reader issues.

Printer idle gear has been substituted, as first step to continue further with the card reader problem solving. As the thread is about card read, the info about the new matherial idle gear substitution will be upload soon in the specific thread

https://www.hpmuseum.org/forum/thread-15625.html

Related to printer, I point out than during light sanding one of the advance paper wheels to improve drag, one got disintegrated in nearly one quarter of circumference, Oh , Jesus!, problems does not stop growing.

Nevertheless, as the advance wheels stay in place and still make advance the paper properly, I am keeping by the moment the printer wheels as they are, hoping to come back for that issue latter on.

I found a reference for the advance wheels substitution, guide in a slide show format created by Ignazio Cara (Italy), cited in this old forum thread.


https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=216173

But the link is not working, Grrrr.... Is there some other site where the slide show can be found?



Coming finally to the card reader,… the clutch show signs of some previous repair work, but not an high level job.

The aluminum sleeve is somehow deformed (it seems to have been pressed with pliers to increase grip). Some kind of wire and soft silicon was found inside.

My “practical” decision has beens to keep the joint, but just reinforce the clutch with a superglue drip inside the sleeve.

After reassembling, the light squeal some time was heard disappeared. Now the card reader noise when reading cards seems to me consistent and acceptable (can be heard in the audio on to the vids below).

Nevertheless the syndrome “only read at low batt level” still continues.

In brief, after substitution of card reader wheels, clutch fix and C6 cap replacement (mesauring a very low capacity once soldered to the PCB, see my previous post):

At normal battery charge level, the card reader error continues, as you can see in the vid

https://youtube.com/shorts/qYyeVBTgHjo

Nevertheless, when lo-battery red dot appears, the cards are read.

https://youtube.com/shorts/UJBM0eFX29w

Please, note that the noise in this last condition is different, a lower sound, but the card transit time seems to be similar, Do you agree?

May be the lo-batt condition reduces the card speed and these makes easier to read the card?

Regards