HP Forum Archive 06

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HP-41C Message #1 Posted by Otavio Gaino on 12 Nov 2001, 11:13 a.m. I am looking for eletronic drawing of HP-41C, that show the connection between the "logicboard", "keyboard" and "displayboard". Anybody could help me?? Thanks

Re: HP-41C Message #2 Posted by Vieira, Luiz C. (Brazil) on 12 Nov 2001, 3:29 p.m., in response to message #1 by Otavio Gaino Olá, Otávio. (Try these links:)Tente esses links: http://library.hp41.org/HP41/LibView.cfm?Command=Download&Class=HP41&ItemID=34 http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=2 The schematics reffers to the earlier 41's (fullnut). Good luck.

Re: HP-41C Message #3 Posted by Thepthai Tabtieng on 12 Nov 2001, 4:23 p.m., in response to message #2 by Vieira, Luiz C. (Brazil) I have the same question, except I have already read the instruction by Stefan Vorkoetter. I started to wire up the connections between the "keyboard" and "CPU" boards, however, I have a problem with the 4 wires in the middle row. I cannot tell from the picture which spots to wire up. The top and bottom 16 pins are obvious from the way the plastic connector is seated. Any help from someone would be greatly appreciated.

Re: HP-41C Message #4 Posted by Vieira, Luiz C (Brazil) on 12 Nov 2001, 4:34 p.m., in response to message #3 by Thepthai Tabtieng Hello; The wiring suggested at Mr. Vorkoetter is somewhat difficult to achieve for those whitout required equipment and previous experience. I would try it myself as the last tryout, when the zebra connectors are no longer available OR the golden-plate itself is of no good connection at all. This is a very delicated situation that must be considered. The wiring sequence is fully symetrical, say, think of the logicboard over the LCD/Keyboard. All pads are lined up and there is a single zebra-connector between them, so wiring should follow the same sequence for all pads. Cheers.

Re: HP-41C Message #5 Posted by Thepthai Tabtieng on 12 Nov 2001, 5:40 p.m., in response to message #4 by Vieira, Luiz C (Brazil) Eventhough it is too late now since I already have soldered most of the connections, but where does one get a replacement zebra connector? My old one deteriated so much that I could not use it anymore. The wiring sequence is symetrical and appears to be hooking up 32 pins on the CPU to the corresponding spots on the keyboard below, but if you read Mr. Vorkoetter instruction carefully, there are 4 extra wires that he described as "middle row" that do not appear to be there on the zebra connector. The reason I am asking is that I have soldered up all 32 connections that are obvious from the zebra connectors but when I power up the unit, I get a beep and "* 1" on the LCD. It does not seem to response to anything except when I hit the ON button.

Re: HP-41C Message #6 Posted by Vieira, Luiz C. (Brazil) on 12 Nov 2001, 6:41 p.m., in response to message #5 by Thepthai Tabtieng Hello; all I can tell you is that the calculator shonw there is a 41CX, fullnut type. I must confess I do not know if there are extra connections for this particular model. I have one 41CV fullnut (logic board + LCD/Keyboard), and I do not remember it having extra connections. The zebra connector is standard type. I read some posts in here about where to find them. Try this link: http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv006.cgi?read=11365 There are lots of suggestions on how to get a zebra connector. Now it's time for Mr. Duell get in the round. Good luck. That's as far as I can go.

Re: HP-41C Message #7 Posted by Thepthai Tabtieng on 12 Nov 2001, 7:06 p.m., in response to message #6 by Vieira, Luiz C. (Brazil) Thanks Luiz for your response. Hearing from someone is sometimes enough to motivate me to try harder to get my 20 year old HP41CV that my dad gave me to work again. My fingers are still crossed on this one. Let's see if I can dig anything out of the schematic.

Re: HP-41C Message #8 Posted by Vieira, Luiz C (Brazil) on 12 Nov 2001, 7:22 p.m., in response to message #7 by Thepthai Tabtieng Hello; just to put some fuel. My third 41 (CV, fullnut) was in a box for about eight years, spread around it (dismantled). I found in here the informations and strenght for putting it to work. At least till today. Fortunately, no problems at the zebra connector between logic board and LCD/Keyboard. If support is what you need, you're at the right place. Success.

Re: HP-41C Message #9 Posted by Otavio Gaino on 13 Nov 2001, 12:39 p.m., in response to message #3 by Thepthai Tabtieng I have the same problem, but with the diagram I hope to fix may old HP using the instruction by Stefan Vorkoetter, but I have the intention to use glue to cover and to protect wires after soldiers... I tell you later....if work... or not... By..

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