HP-67 Reads cards but does not write

[Trevor Gale]

I have searched the forums about this but not found a similar thread, hence my question here.

I have amongst my HP calculators which I still use, an HP-67 which I went to use 2 or 3 weeks ago and found that it would not save a program I wrote on it. It simply returns the LED display "Error" after passing a card through the reader/writer slot.

It passes the card perfectly well, but has not actually written the program or anything on it - I checked this on my HP-97, as well as passing the card again through the '67 in 'run' mode to read it, which only returns the "Error" display again.

This HP-67 will read a card almost every time perfectly well - I have tried cards from an original HP application pack and also a card containing a program which I wrote and then saved on the HP-97, both of these are read perfectly by the HP-67.

There is no question of any "gummy wheel" problem in this HP-67, the battery is a new one correctly charged (checked in my electronics workshop); also I have tried this with many various cards (some unused, new, which I subsequently checked on my HP-97 and HP-41's), and I was not so stupid as to have the corner "write protect" cut away! All other functionality of this HP-67 works just fine.

Does anyone have any constructive ideas?