HP Forum Archive 21

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Voyager battery installation sequence Message #1 Posted by Peter Murphy (Livermore) on 10 Aug 2012, 2:44 p.m. Voyager backplates indicate (with "# 1") that the rightmost battery is to be inserted first. Why so?

Re: Voyager battery installation sequence Message #2 Posted by Luiz C. Vieira (Brazil) on 10 Aug 2012, 3:04 p.m., in response to message #1 by Peter Murphy (Livermore) IIRC, this one is the RAM backup (or main) power source, so you can change batteries without the risk of memory loss. Again, IIRC! Luiz (Brazil)

Re: Voyager battery installation sequence Message #3 Posted by uhmgawa on 10 Aug 2012, 5:15 p.m., in response to message #2 by Luiz C. Vieira (Brazil) Quote: IIRC, this one is the RAM backup (or main) power source, so you can change batteries without the risk of memory loss. Actually the 3 cells are in series and there are no provisions for less than three cells to hold up the internal power rail. The internal 10uF tantalum cap is what functions quite well (almost to a fault) as a memory "keep alive" during cell replacement. But I have not seen any reference signifying the relevance of #1 on the rear bezel plate. I'm leery it is a recommendation of cell replacement sequence as you'd be fighting with the positive terminal compression spring if cells were installed from #1 onward. I find it easier to stack against the spring which can be compressed in the process and released after the last cell is dropped in. If shorting is really a concern in any scenario, use a strip of paper over the last cell's negative tip during insertion, pulling it out after the cell is seated.

Re: Voyager battery installation sequence Message #4 Posted by Randy on 10 Aug 2012, 6:17 p.m., in response to message #3 by uhmgawa Quote: ...But I have not seen any reference signifying the relevance of #1 on the rear bezel plate. It's in the manual. Honest. Quote: I'm leery it is a recommendation of cell replacement sequence as you'd be fighting with the positive terminal compression spring if cells were installed from #1 onward. You're forgetting about the original design with symmetrical contacts. When the design changed and the coil spring appeared, they never changed the manual to reflect the different configuration. I agree: with later units, it is better to invert and stack from the spring end.

Re: Voyager battery installation sequence Message #5 Posted by uhmgawa on 10 Aug 2012, 7:39 p.m., in response to message #4 by Randy Quote: It's in the manual. Honest. The Owners Handbook? I couldn't find any mention of it most notably in Appendix F. Nor anywhere else in the mohpc OCR version cd03/manuals/15c_c.pdf though I certainly may have missed it. Quote: You're forgetting about the original design with symmetrical contacts. Indeed I was. But I'm admittedly myopic here. The early mechanical voyager version cost reduced to its single PCB successor should be studied by engineering students as an rare example of improving a design along with a manufacturing cost reduction. Quote: When the design changed and the coil spring appeared, they never changed the manual to reflect the different configuration. I agree: with later units, it is better to invert and stack from the spring end. I think both designs can enable cell shorting, but the positive spring terminal version is likely worse. Not really a concern as even if a single cell is momentarily shorted you wouldn't drop the tantalum cap rail voltage enough at ~3V to lose memory contents.

Re: Voyager battery installation sequence Message #6 Posted by Raymond Del Tondo on 10 Aug 2012, 9:25 p.m., in response to message #5 by uhmgawa Quote: The early mechanical voyager version cost reduced to its single PCB successor should be studied by engineering students as an rare example of improving a design along with a manufacturing cost reduction. Another extreme improvement was moving the battery door to the back side of the Clamshell. That's how it should have been from the beginning:-) BTW: Anyone implemented a 28S machinery into a 19BII back door housing?

Re: Voyager battery installation sequence Message #7 Posted by Jeroen Van Nieuwenhove on 11 Aug 2012, 11:37 a.m., in response to message #5 by uhmgawa Quote: The Owners Handbook? I couldn't find any mention of it most notably in Appendix F. Nor anywhere else in the mohpc OCR version cd03/manuals/15c_c.pdf though I certainly may have missed it. I couldn't find it in the MOHPC DVD manuals either, but in my own Dutch 11C Owners Handbook there is indeed an instruction (in appendix D) to install the batteries starting with the side of the battery compartment away from the rubber foot adjacent to it. This is not mentioned in the English 11C Owners Handbook nor in the English 15C Owners Handbook.

Re: Voyager battery installation sequence Message #8 Posted by Randy on 10 Aug 2012, 4:50 p.m., in response to message #1 by Peter Murphy (Livermore) Ah, another one that forgot what's in the manual ;-) Hold the calculator vertically so #1 is at the bottom position of the three cells. Using gravity, you stack them vertically starting with #1. It is the same orientation and procedure for the Pioneers as well. The purpose is to reduce the chance of memory loss. PS for Luiz: This is for the three cell version of the Voyagers, not the later models with the larger cells. Edited: 10 Aug 2012, 4:52 p.m.

Re: Voyager battery installation sequence Message #9 Posted by Luiz C. Vieira (Brazil) on 10 Aug 2012, 5:18 p.m., in response to message #8 by Randy Oops! Believe me, I never noticed that those inscriptions were a "#1" mark! After so many years using Voyagers... Indeed, what do we know! Thanks for pointing that out. I was sure it was about the new ones with two cells, would never guess. Luiz (Brazil) Edited: 10 Aug 2012, 5:19 p.m.

Re: Voyager battery installation sequence Message #10 Posted by Raymond Del Tondo on 10 Aug 2012, 9:16 p.m., in response to message #8 by Randy Quote: Hold the calculator vertically so #1 is at the bottom position of the three cells. Using gravity, you stack them vertically starting with #1. It is the same orientation and procedure for the Pioneers as well. The purpose is to reduce the chance of memory loss. A small correction. If I change batteries in the Voyagers, I usually just flip the unit around so that the batt compartment is in the upper left corner, and then insert the batts with plus pointing to the _left_, and the spring is on the left. On the Pioneers, I flip the unit around, and the batt compartment is on the top edge. Then I insert batteries with plus pointing to the _right_ , since the spring is on the right side. I always insert the batts with the same hand, so moving the calcs into a position where both springs (Voyagers and Pioneers) are south seems very unergonomic for me, since in your example the Voyagers batt compartment would be on the lower left side, and the Pioneer's batt compartment would be on the mid to upper right side. Aside from that, the German manual does not mention any insertion order. It only says that the plus pole of each battery has to point to the nearest rubber foot. Relevant pages are 230 - 233 in manual 00011-90002 German Rev. B 2K-7.83 . The photos in the manual are from the first implementation with two 3-finger springs. Edited: 10 Aug 2012, 9:27 p.m.

Re: Voyager battery installation sequence Message #11 Posted by Cameron Paine on 12 Aug 2012, 4:38 a.m., in response to message #1 by Peter Murphy (Livermore) After reading a few posts in this thread I flipped a 16C over and opened the battery compartment. The one I'm looking at is a 3-battery model (2840A*) and there is a translucent plastic cup at the #3 cell end of the compartment. If I were to populate slot #3 last, the battery would bend the side of the plastic cup so that it covers the terminal. This means that slot #3 must be filled first or second and #1 must be filled second or last. I'm not making a point; just sharing an observation. Cameron

Re: Voyager battery installation sequence Message #12 Posted by Les Koller on 12 Aug 2012, 9:04 a.m., in response to message #11 by Cameron Paine That is exactly the way my 15C of 30 years ago was. Had a plastic cup every bit as big as the battery, so that the battery had to be inserted at that end first.

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