HP67 display problem Message #1 Posted by Nick Kronenberg on 27 Dec 1999, 3:04 a.m.
Hello, UPN fans,
it’s me again (see my question below).
Even owning additionally to this 28C a HP41CX with card reader a still love my third HP calculator, an old HP67 being bought in the 80’s at a horrible price! After some years of not being used the part now is showing a display failure. All „c" segments on all three modules are non functional. I have found the helpful information of A.Knight (Thanks!) and did some measurements during Christmas holidays.
Pin 3 on all modules (anode c) - even showing a signal - (measured by scope) is kept at an non activated level (in relation to other anodes). As far as I could identify the signal it is been generated by 16pin IC 1858-0050-1D (A.Knight thinks this being the cathode driver, but I assume he is not right).
Does anyone have an idea what could be the root cause and can give assistance (Probably a „dead" signal path from the main controller is causing trouble?). My e-mail address is
s.u.k.kronenberg@t-online.de
I would love to make the machine work again! Thank you very much in advance!
Nick Kronenberg (German UPN fan)
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