HP34C Repair



#2

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.

Could a missing component be the reason?

Who could provide me with a electronic schematic, please?
Does anyone have servicing instructions?

Thank You in advance


#3

> 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.

----------------

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


Possibly Related Threads...
Thread Author Replies Views Last Post
  RPN hp20s and lcd hp34c proposals Jose Poyan 11 940 04-29-2011, 08:17 PM
Last Post: Scott Newell
  HP34C Black Scholes Model Ed Austin 2 365 05-18-2009, 07:40 PM
Last Post: Ed Austin
  HP34C Manual - 30 years ago Ed Austin 12 1,550 11-20-2008, 05:19 PM
Last Post: Ed Look
  HP34c decimal point/comma interchange for display JaSon 2 415 04-30-2007, 05:58 AM
Last Post: Mike T.
  HP34C Keyboard Problem Mike T. 3 391 08-26-2006, 01:16 PM
Last Post: Mike T.
  HP34C Pyerre 14 1,095 06-06-2006, 02:11 AM
Last Post: Eric Smith
  HP34C Fault Mike T. 4 389 01-06-2006, 12:53 PM
Last Post: Mike T.
  HP34C dot instead of comma Denis 4 456 04-26-2005, 03:30 PM
Last Post: Tony Duell
  hp34c compatible charger? marais 5 577 08-02-2004, 03:30 PM
Last Post: marais
  HP34C on tv commercial marais 28 1,766 06-18-2004, 01:51 AM
Last Post: Karl Schneider

Forum Jump: