HP Forum Archive 20

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HP41CV faulty Message #1 Posted by Steve Hunt on 17 Dec 2011, 11:34 a.m. Hi folks - new to the forum so please go easy with a "newbie". I have an HP41CV (Fullnut I think you call it) which has seen better days - badly corroded battery terminals, and intermittent contact between the logic board and keyboard. Rather than scrap it, I pulled it to pieces and hard-wired the logic board to the keyboard. Temporarily I've connected a 6v supply directly across the appropriate keyboard traces. It doesn't work! Here are the symptoms: At power-up the display shows the "flying duck" in the leftmost display position and the PGRM annunciator is on. None of the keys has any effect except: * Pressing the ON key causes the display to briefly show "MEMORY LOST" and the beep to sound before going back to the original display. * Pressing R/S changes the display to "0," at the left and "00" at the right. Pressing R/S again puts it back to the original display. Before throwing it in the bin I wondered if those symptoms give any pointers to what the fault might be. I've very carefully check my hard-wiring of the logic board to the keyboard - everything looks correct with no shorts. Grateful for any help, Steve

Re: HP41CV faulty Message #2 Posted by Randy on 17 Dec 2011, 12:16 p.m., in response to message #1 by Steve Hunt Anytime a 41 displays MEMORY LOST at power on (other than after a complete reset of memory) is usually a sign of a bad rom or ram. Realistically, the only way to troubleshoot is with the HP 41 service rom.

Re: HP41CV faulty Message #3 Posted by Steve Hunt on 17 Dec 2011, 1:56 p.m., in response to message #2 by Randy Thanks Randy - looks like it's on its way to the bin! Steve

Re: HP41CV faulty Message #4 Posted by Håkan Thörngren on 17 Dec 2011, 2:06 p.m., in response to message #3 by Steve Hunt Do NOT throw it! If it has a good keyboard and LCD, it can probably be salvaged and converted to a 41CL by replacing the logic board. At worst, it will most likely have some use for spare parts!

Re: HP41CV faulty Message #5 Posted by Steve Hunt on 17 Dec 2011, 5:35 p.m., in response to message #4 by Håkan Thörngren Yes - the "bin" in question is the spare parts bin ;) I have 3 other HP41s, so it might come in useful at some stage. Next job is to replace the "crumbling" drive wheel on my card reader! Thanks for the advice, Steve

Re: HP41CV faulty Message #6 Posted by dinamarco on 26 Dec 2011, 8:23 p.m., in response to message #4 by Håkan Thörngren How can I do it? How "transform" my HP-41CV into a HP-41CL? regards...

Re: HP41CV faulty Message #7 Posted by Kerem Kapkin (Silicon Valley, CA) on 27 Dec 2011, 12:45 a.m., in response to message #6 by dinamarco Hi dinamarco, Checkout this 41CL Link . You will find all the necessary information about the 41CL upgrade. Also checkout this for further information.41CL wiki link Regards, Kerem

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