HP-67 Reads cards but does not write

[Trevor Gale]

My apologies for the 'long' delay in responding, however I have the 'flu or a bad cold... and waited for a (delayed) deivery of some extra workshop spares.

I replaced the two 22uF tantalum capacitors and the 6.8uF tantalum on the CRC card, and also replaced the 47uF and the 22uF capacitors in the mainboard supply.
I have double-checked the head connection wiring, checked for normal winding resistance, and for safety I have checked all solder joints on the CRC board and that it sits properly on the pin-points of the mainboard. Batteries (I have more than the one set) fully charged.

The result is that it began to write occasionally (i.e. readable on my HP-97 and an HP-67 from a collague) but still not read any cards; after a few passes it now no longer writes successfully (perhaps 1 in 20 times it will write correctly)... this is indeed a very frustrating fault to follow up.

I am not thinking of looking again at the motor working, clutch status, and anything else that comes to mind; having also checked how the card 'feels' though the path I detected no obstacle of change which was not normal...