Re: HP34C Repair
Message #2 Posted by Vassilis Prevelakis on 22 Feb 2003, 7:12 a.m.,
in response to message #1 by Ulrich Viebahn
> I bought a HP34C whose display stays dark when I am applying 3 Volts to the battery contacts.
> Disassembling the calculator I found on the small analog board two cut wires.
Without additional information on the location of the "cut wires" I can only speculate. If by "cut wires" you mean wires hanging from the PCB but going nowhere, they could be test leads added by the previous person who tried to fix the calculator. In this case your chances of fixing it are slim.
If by "cut wires" you mean a jumper that was removed by cutting the endpoints close to the PCB, then you may be looking at the US/EU decimal point jumper. I think that if the jumper is in place, the Series 30 calculators display a dot (.) as the decimal point and a comma (,) as a thousand separator. If the jumper is removed then the two symbols are reversed. Note that I could have this the other way round as I am away from my notebook.
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Since you have disassembled tha calculator you should note that the analog PCB is connected to the main keyboard assembly via a pressure pad. Since the LED display is connected to the main keyboard assembly via a another pressure pad, if either pads are not making contact, the display will be blank. Verify that good contact is made on the analog PCB - keyboard assembly interface. If this is OK, then take out the LED display assembly and reseat it. This may fix the problem.
Good luck.
**vp
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