Dead HP 35

[krazyk]

Thanks Tony

I have printed out the circuit diagrams and have tested for Phi1 and Phi2 clocks at both the test point to the right of the logic board and more recently from the ini and ini2 locations on the keyboard connectors.

In both cases I see voltage but no regular CLOCK pulses which seems consistent with a fault on the keyboard PCB associated with the ANODE IC and/or the grey furry solder from underneath where the battery box corrosion was.

I am about to resolder all the grey furry vias and solder points associated with the LED display and support ICs. Will do it gradually and will try not to cook the precious ICs. Was just concerned about the plastic overlay that HP have placed on the board.

Has anybody had this NO CLOCKS fault before here associated with this CLASSIC class of HP calculators?

Kris