Hp-41C card reader - dead

[AndiGer]

(05-13-2020 01:31 PM)Vintage63 Wrote:  I fiddled around with the forks and the internal copper bits, the curvy one and the one close to the magnetic head.
I left a card in the system and closed it.
I attached it to the calculator and the system sprung to life.
I could not switch it off at all. The card would not move but the motor kept turning.
I used a screw driver to try and get more pression on the card nothing.
I pulled the card out and the reader stopped.
All I get now is a MALFUNCTION error on the display.
I used the abrasive card a few times, it doesn't change anything.
I switched to PRGM mode and tried to save the routine, inserting the card shows RDY 01 OF 1 the card scrolls but the result is always MALFUNCTION

The O-Rigs seem to be working as the card is pulled through

I recall reading about this issue but will have to browse my bookmarks in order to find the reason of this.

Maybe that's the other fork not closing (correctly). This is the head switch. It must close at a specific point - after the motor switch is enabled - when the card goes thru. You can test it the same way with the DMM at the correct test point on the top PCB.