Re: HP-41C with weak display Message #2 Posted by David Smith on 3 Aug 2002, 12:50 p.m., in response to message #1 by Jose Goncalves
Try cleaning the circuit boards with 91% isopropyl alcohol. I have seen this happen when old solder or some other gunk gets on the boards. Clean the CPU, keyboard, and back of the LCD. Another symptom that shows up is a display that only shows up while a key is pressed down.
Be careful not to get the alcohol on or under the LCD window. It can cause it to appear fogged. On full nut machines you can remove the LCD module and repolish the window (but this is a fairly tricky thing to do).
Another cause may by the temperature compensation circuitry in the LCD drive system.
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