Re: HP41CV drains battery. Schematics? Message #13 Posted by Harald on 18 Mar 2012, 6:13 p.m., in response to message #12 by Luiz C. Vieira (Brazil)
Quote:
Have you checked if there is any kind of short-circuit between any circuit lines of the keyboard?
I can't find anything there.
Quote:
There is also one fact: the first picture (top-to-down) shows a more recent PCB, while the second one shows an earlier version. Chances are that the LCD's are different.
I don't think they are different. I got the other main board to work in the good calculator. And briefly the other way round too. But once I take the battery out and put it back in, the calculator draws a lot of current and doesn't appear to turn on.
Quote:
It does not explain the high-current drain, and a faulty LCD controller might be the best guess.
Chances are you will easily find a replacement in Europe (you are in German, right?). I have at least one good LCD driver with a broken LCD, so if you are not that lucky finding a replacement, contact me and I'll find a way to send it to you. It is fairly easy to replace the LCD in the LCD module (LCD+drivers assembly).
I think it must be a problem with the LCD driver.
How can I disassemble the display? Is it possible to leave all the heat stakes of the keyboard in place? I can have a look on ebay for a broken HP41. If you want to sell your broken LCD with the good driver, I am sure we can agree on something.
|