Re: HP41CX halfnut circuit diagram Message #2 Posted by Tony Duell on 24 Nov 2005, 6:31 a.m., in response to message #1 by Christoph Klug
I certainly have it (I have the full 41 service manual which seems to cover all versions, fullnut and halfnut). I thought it was on TOS.
However, there are no PCB layouts in said manual (component-level repair was not supported by HP), so it's not going to be a lot of help in finding the battery connections. I have powered up a halfnut by connecting wires to the logic PCB, I seem to remember tracing the connections from the contacts for the I/O flexiprint.
It's been a long time since I did this, so check this carefully, but I seem to remember that the -ve battery contact is the -ve side of the largest capacitor on the board, and the +ve side goes to one of the connections to the 2 diodes soldered together near that capacitor.
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