|Re: HP-34C LED display|
Message #11 Posted by Vieira, Luiz C. (Brazil) on 5 May 2004, 5:38 p.m.,
in response to message #1 by Imran Farooq
keep in mind that there are two "spice spieces": one with soldered IC's AND LED assembly, and another one built as a "sandwich", where IC's terminals are pressed to a flex circuit. As you have already opened your 34C (great calculator!) you may tell which one is yours.
I replaced a corroded (as Nelson mentioned; by leakage, no hope for them...) LED assembly in one solderless spice for another one removed from a soldered unit. It seems to me that they are electrically equivalent, but I'd like to know from other contributors, please, if there is any sort of limitation or incompatibility. At least for it worked pretty fine, but you must clean the LED assembly terminals in a way you do not experience bad contact further problems. Don't use any sort of scrapper or sand paper, instead carefully use alcohol to remove soldering flux and after that, apply some metal polisher to obtain a smooth, regular surface, better for contact with pressure; remember cleanning it well after this. If yours is a soldered unit and you are going to use a LED assembly from a solderless one, you'll just have to solder it in place. JUST be carefull aligning it well, if so.