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Compaq Portable III CMOS Battery

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    Compaq Portable III CMOS Battery

    I'd like to replace the CMOS battery on my Compaq Portable III 386.
    OK, here's the description:I think it is located near the top of the board, and ISN'T soldered in. It has a total of 4 pins, or "legs," and is inscribed: Lithium Battery-1.5AH-3.4V-Compaq Part#107157-001-Eagle Picher Ind (manufacturer?)-It appears to have two separate cells, plus the other electronic components that are located above the cells.
    Am I right that this is it?
    Could a replacement be cobbled together with common stuff?(Like with stuff from Radio Shack?)
    I need some guidance here.(Stop me before I kill again!)

    cgrape2

    #2
    Originally posted by cgrape2 View Post
    I'd like to replace the CMOS battery on my Compaq Portable III 386.
    OK, here's the description:I think it is located near the top of the board, and ISN'T soldered in. It has a total of 4 pins, or "legs," and is inscribed: Lithium Battery-1.5AH-3.4V-Compaq Part#107157-001-Eagle Picher Ind (manufacturer?)-It appears to have two separate cells, plus the other electronic components that are located above the cells.
    Am I right that this is it?
    http://www.etiexpress.com/ProductAdv.aspx?pid=8806 indicates that part number 107157-001 is a battery for the Compaq Portable III

    Originally posted by cgrape2 View Post
    Could a replacement be cobbled together with common stuff?(Like with stuff from Radio Shack?)
    Probably, but in constructing a replacement, be aware that there are discussions on the Internet about batteries and cells exploding when soldered. One suggestion to get around that problem is to use battery holders.

    Comment


      #3
      Yep,that's exactly what I had in mind.3.3V batteries seem hard to find(my local Radio Shack didn't seem to have any),but 3.6V batteries are fairly easy to locate.Would that voltage difference(0.3V)be a problem?
      I think I can handle the fairly simple job of splicing wires to the old connection,so it's just this question I have now.
      I also found the disassembly PDF pretty useful for the physical breakdown,Disassembly\reassembly.
      Thanks for the reply.
      cgrape2

      Comment


        #4
        I very much doubt that 0.3V will really blow anything up. But if you feel concerned, you could try backwards; 3.0V batteries are pretty common. I replaced a 286 laptop's 3.6V battery with a 3.0V battery and it holds settings just fine.
        Anyone got an Intel Inboard 386/PC memory module? Still looking for that Kingston 486/Now too.

        Comment


          #5
          Originally posted by cgrape2 View Post
          Yep,that's exactly what I had in mind.3.3V batteries seem hard to find(my local Radio Shack didn't seem to have any),but 3.6V batteries are fairly easy to locate.Would that voltage difference(0.3V)be a problem?
          I think I can handle the fairly simple job of splicing wires to the old connection,so it's just this question I have now.
          In comes down to the RTC/CMOS chip (could be part of a chip set) used in the computer. Chips such as the 146818 (used in the IBM 5170) and BQ3285 can handle up to 7 volts.

          I don't think an increase of 0.3V is going to be an issue in this case. I think it would be very odd for a RTC/CMOS chip to handle 3.3V (or was that 3.4V) but not handle 3.6V (with 3.6V being as common as it is).

          If you want to be 100% certain, we would need to identify the RTC/CMOS chip used in the computer then find its specifications.

          Something to consider. The battery component of your 107157-001 module might be 3.6V but because of the "other electronic components" you write of, there could be a small voltage drop resulting in the module supplying 3.3V (or was that 3.4V).

          Comment


            #6
            You are correct that 3V batteries are cheap and common.Even a couple of AAA or AA batteries should work.I haven't dissected the old module yet,I'll report back when I do.Thanks youall for the help and insight!
            cgrape2

            Comment


              #7
              cgrape2
              How you decided this problem with batarrey? Because i have the same problem.
              And i dont understand in this compaq portable III we have accumulator or battarey ???
              https://www.facebook.com/retro.pc.net/ my blog (Ukrainian)
              ------------------------------------------------------
              i like IBM,Compaq and SUN computers

              Comment


                #8
                I went with a battery holder and 2 AAA batteries.I soldered the old wire with the connector to the battery holder and it worked!
                Accumulator? Could that be a Capacitor???
                cgrape2

                Comment


                  #9
                  I found this site. They are 10 bucks 3.6V (B9632T-0) made in USA. I'll be getting 3. One for my old 286 clone desktop, one for my Toshiba T3200 and one for my newly acquired Compaq Portable 386-20 (10 bucks on Crag's list :P ).


                  http://www.oemreplacementbatteries.c...0-mAh-2736.htm
                  PS/2s--M-30,M-40SX,M-50Z with AOX Micromaster 386DX, M-57, M-70, M-77, M-80

                  Comment


                    #10
                    OK,now that seems to ba a real deal! So much better than a hacked together battery.Thanks for the info!!!
                    cgrape2

                    Comment


                      #11
                      Originally posted by cgrape2 View Post
                      OK,now that seems to ba a real deal! So much better than a hacked together battery.Thanks for the info!!!
                      cgrape2
                      No Problem! I just have a passion for old PCs and restoring them. Such a fun hobby and glad to help.
                      PS/2s--M-30,M-40SX,M-50Z with AOX Micromaster 386DX, M-57, M-70, M-77, M-80

                      Comment


                        #12
                        Hello,

                        I have the same error on my "new" Compaq Portable III. I've found a Dallas DS12887 battery, would this work? I know little about this computer, so I wish to know how to fix this! It was listed as working, but I can't do much unless I fix this.

                        Also, will I have to install an OS once I've put in the battery? Or will I have to run a diagnosic disk?


                        James B

                        Comment


                          #13
                          Allied Electronics sells the original EaglePicher battery without the blocking diode and 1.6k resistor.

                          Original Compaq part number: 107157-001
                          Original EaglePicher part number: LTC-7PMP-F-S2 (no longer available unless you have very deep pockets)

                          Currently available EaglePicher part number: LTC-7PMP (You will have to add a series diode and resistor externally)
                          Allied part number: 710-5025

                          Enjoy

                          Comment


                            #14
                            I'm now trying to do something with mine too. On the EaglePicher data sheet, it says * Battery contains diode and resistor protection (IN5817 diode, 1.6k resistor). So would it still be safe to wire up a different style battery without this protection?
                            LTC-7PMP-F-S2 Bottom.jpgLTC-7PMP-F-S2 Top.jpg

                            Comment


                              #15
                              I need a new CMOS battery...

                              LTC-7P 3.5V 750 mAh Lithium (w/ PCB Termination) => this one is available now...
                              LTC-7PMP 3.5V 1500 mAh Lithium (w/ PCB Termination) => this has to be order 5 weeks lead time...

                              Does the mAh rating matter? Could I use the LTC-7P battery with my compaq portable III ? I do not have a spec sheet to tell me what the minimum mAh would be... seems like it would be that big of a deal since its just keeping the settings, clock?? right? hmm.

                              *Edit*
                              I just pulled the battery my part# 107157-001 printed on the black box... those batteries (there's 2 in there) are glued in there pretty good w/ the diode, resistor. I would like to reuse the black box, any tips in removing those batteries w/o damaging the black box? I am new to electronics... anyone have a drawing to show where to solder the diode(s) and resistor(s) in relation to the batteries...


                              Thanks in advance!
                              Last edited by raisedabar; September 6, 2013, 11:20 AM.

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