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HP 85 market value

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  • Mike Loewen
    I have the opportunity to buy a HP 85, with 2 16KB memory modules and a ROM drawer. According to the seller, it used to work, but would not power up
    Message 1 of 12 , Jun 22, 2012
      I have the opportunity to buy a HP 85, with 2 16KB memory modules and a
      ROM drawer. According to the seller, it used to work, but would not power
      up yesterday. I offered $50, and he countered with $60: is it worth that?


      Mike Loewen mloewen@...
      Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
    • Dave McGuire
      ... I d drop $60 on an HP-85 in a New York minute. I haven t looked at the power supplies in those, but they can t be terribly complicated. -Dave -- Dave
      Message 2 of 12 , Jun 22, 2012
        On 06/22/2012 01:54 PM, Mike Loewen wrote:
        > I have the opportunity to buy a HP 85, with 2 16KB memory modules and a
        > ROM drawer. According to the seller, it used to work, but would not power
        > up yesterday. I offered $50, and he countered with $60: is it worth that?

        I'd drop $60 on an HP-85 in a New York minute. I haven't looked at
        the power supplies in those, but they can't be terribly complicated.

        -Dave

        --
        Dave McGuire, AK4HZ
        New Kensington, PA
      • Rilker Frota Cavalcante
        HI Mike, $60 is a good price for ROM drawer and 2 memory modules. THE 85 (A or B) will be almost free. Parts for this machine is not easy to find. Cheears.
        Message 3 of 12 , Jun 22, 2012
          HI Mike,

          $60 is a good price for ROM  drawer and 2 memory modules.

          THE 85 (A or B) will be almost free. Parts for this machine is not easy to find.

          Cheears.
        • Dave McGuire
          ... Subsystems, yes, but components...if it s just something in the power supply, which is likely, there shouldn t be anything too exotic in there. -Dave --
          Message 4 of 12 , Jun 22, 2012
            On 06/22/2012 01:59 PM, Rilker Frota Cavalcante wrote:
            > $60 is a good price for ROM drawer and 2 memory modules.
            >
            > THE 85 (A or B) will be almost free. Parts for this machine is not easy
            > to find.

            Subsystems, yes, but components...if it's just something in the power
            supply, which is likely, there shouldn't be anything too exotic in there.

            -Dave

            --
            Dave McGuire, AK4HZ
            New Kensington, PA
          • Matt Patoray
            Yes if it is just the power supply, those are easy they are just your basic linear power supply, let s hope when he plugged it in he did not let any magic
            Message 5 of 12 , Jun 22, 2012
              Yes if it is just the power supply, those are easy they are just your basic linear power supply, let's hope when he plugged it in he did not let any "magic smoke" out of anything that would be more unobtanium like the power transformer, caps will need replaced anyway if you want it to be reliable/safe but I am sure you knew that already :) 

              In fact I would start with replacing ALL of the Electrolytic or Titantlium caps without question. I like Panasonic 105 or 125 degree c caps low ESR if you can get them, Titantlium caps have a VERY nasty habit of failing catastrophically and burning holes in the PCB, they can be replaced by electrolytics no problem. You may need to get creative with mounting the replacements as you may be able to only find the values you need in radial instead of the axial packaging originally used.

              Just a few tips I have learned when restoring stuff like my RCA TK-86 3 Plumbicon ENG/EFP camera.

              Matt 

              Sent from my iPhone

              On Jun 22, 2012, at 2:02 PM, Dave McGuire <Mcguire@...> wrote:

               

              On 06/22/2012 01:59 PM, Rilker Frota Cavalcante wrote:
              > $60 is a good price for ROM drawer and 2 memory modules.
              >
              > THE 85 (A or B) will be almost free. Parts for this machine is not easy
              > to find.

              Subsystems, yes, but components...if it's just something in the power
              supply, which is likely, there shouldn't be anything too exotic in there.

              -Dave

              --
              Dave McGuire, AK4HZ
              New Kensington, PA

            • Dave McGuire
              ... Be careful here; if it s a switching supply, replacing them with a capacitor with higher-than-needed ESR can result in anything from inefficient operation
              Message 6 of 12 , Jun 22, 2012
                On 06/22/2012 04:15 PM, Matt Patoray wrote:
                > In fact I would start with replacing ALL of the Electrolytic or
                > Titantlium caps without question. I like Panasonic 105 or 125 degree c
                > caps low ESR if you can get them, Titantlium caps have a VERY nasty
                > habit of failing catastrophically and burning holes in the PCB, they can
                > be replaced by electrolytics no problem. You may need to get creative
                > with mounting the replacements as you may be able to only find the
                > values you need in radial instead of the axial packaging originally used.

                Be careful here; if it's a switching supply, replacing them with a
                capacitor with higher-than-needed ESR can result in anything from
                inefficient operation to FIRE. A lot of times, tantalum capacitors are
                chosen specifically for low ESR. One needs to understand the circuit
                before just swapping out components...(saying this not to you Matt, but
                to others here who may not know) Capacitance and working voltage are
                just two of a capacitor's many parameters!

                > Just a few tips I have learned when restoring stuff like my RCA TK-86 3
                > Plumbicon ENG/EFP camera.

                That certainly is an awesome device.

                -Dave

                --
                Dave McGuire, AK4HZ
                New Kensington, PA
              • Mike Loewen
                ... The HP-85 uses a switcher. I ve worked on a few power supplies, in my day. :-) Schematics are available. I m picking it up on Monday. Thanks for the
                Message 7 of 12 , Jun 22, 2012
                  On Fri, 22 Jun 2012, Matt Patoray wrote:

                  > Yes if it is just the power supply, those are easy they are just your
                  > basic linear power supply, let's hope when he plugged it in he did not
                  > let any "magic smoke" out of anything that would be more unobtanium like
                  > the power transformer, caps will need replaced anyway if you want it to
                  > be reliable/safe but I am sure you knew that already :)

                  The HP-85 uses a switcher. I've worked on a few power supplies, in my
                  day. :-) Schematics are available.

                  I'm picking it up on Monday. Thanks for the feedback, everyone.


                  Mike Loewen mloewen@...
                  Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
                • Matt Patoray
                  Dave, You are very much correct, I was just talking linears not switchers, low ESR s are a good idea in any way. I know I was ok with the camera because the
                  Message 8 of 12 , Jun 22, 2012
                    Dave,

                    You are very much correct, I was just talking linears not switchers, low ESR's are a good idea in any way. I know I was ok with the camera because the internal supply is a linear, the tant's where used because of space constraints  and they where the smallest available in 1981 :) also added 50% to the working voltage on the replacements. 

                    Evan may get mad at me for this, this is what I was working on, it does have a CPU in it and was from Camden :)

                     image.jpeg

                    Matt 

                    Sent from my iPhone

                    On Jun 22, 2012, at 4:51 PM, Dave McGuire <Mcguire@...> wrote:

                     

                    On 06/22/2012 04:15 PM, Matt Patoray wrote:
                    > In fact I would start with replacing ALL of the Electrolytic or
                    > Titantlium caps without question. I like Panasonic 105 or 125 degree c
                    > caps low ESR if you can get them, Titantlium caps have a VERY nasty
                    > habit of failing catastrophically and burning holes in the PCB, they can
                    > be replaced by electrolytics no problem. You may need to get creative
                    > with mounting the replacements as you may be able to only find the
                    > values you need in radial instead of the axial packaging originally used.

                    Be careful here; if it's a switching supply, replacing them with a
                    capacitor with higher-than-needed ESR can result in anything from
                    inefficient operation to FIRE. A lot of times, tantalum capacitors are
                    chosen specifically for low ESR. One needs to understand the circuit
                    before just swapping out components...(saying this not to you Matt, but
                    to others here who may not know) Capacitance and working voltage are
                    just two of a capacitor's many parameters!

                    > Just a few tips I have learned when restoring stuff like my RCA TK-86 3
                    > Plumbicon ENG/EFP camera.

                    That certainly is an awesome device.

                    -Dave

                    --
                    Dave McGuire, AK4HZ
                    New Kensington, PA

                  • Evan Koblentz
                    We have a working 85B at the museum if you need to compare anything for troubleshooting purposes. I think we have a parts unit too.
                    Message 9 of 12 , Jun 22, 2012
                      We have a working 85B at the museum if you need to compare anything for troubleshooting purposes. I think we have a parts unit too.
                    • joshbensadon
                      I d give $100 for that machine in not working condition and $200 if it was working.
                      Message 10 of 12 , Jun 22, 2012
                        I'd give $100 for that machine in not working condition and $200 if it was working.

                        --- In midatlanticretro@yahoogroups.com, Dave McGuire <Mcguire@...> wrote:
                        >
                        > On 06/22/2012 01:54 PM, Mike Loewen wrote:
                        > > I have the opportunity to buy a HP 85, with 2 16KB memory modules and a
                        > > ROM drawer. According to the seller, it used to work, but would not power
                        > > up yesterday. I offered $50, and he countered with $60: is it worth that?
                        >
                        > I'd drop $60 on an HP-85 in a New York minute. I haven't looked at
                        > the power supplies in those, but they can't be terribly complicated.
                        >
                        > -Dave
                        >
                        > --
                        > Dave McGuire, AK4HZ
                        > New Kensington, PA
                        >
                      • Mike Loewen
                        I picked up the HP-85 (original model) today. As advertised, it does absolutely nothing, but that s okay. It came with: 82903A 16K Memory module (qty 2) -
                        Message 11 of 12 , Jun 25, 2012
                          I picked up the HP-85 (original model) today. As advertised, it does
                          absolutely nothing, but that's okay. It came with:

                          82903A 16K Memory module (qty 2) - only 1 at a time can be used.

                          82936A ROM drawer, with the following ROMS:

                          00085-15001 Mass Storage
                          00085-15002 Plotter/Printer
                          00085-15003 Input/Output
                          00085-15004 Matrix
                          00085-15005 Advanced Prgm.

                          The belts on the printer are in good shape. The rubber on the tape
                          drive capstan has turned to goo (unsurprisingly). The recommended fix is
                          a piece of 3/8" O.D. surgical tubing. The case is noticeably yellowed,
                          but the inside is fairly clean.

                          I'll dig into the power issue, first. The fuse is intact. Into the
                          repair queue, it goes.


                          Mike Loewen mloewen@...
                          Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
                        • joshbensadon
                          ... That s great! Even non-working, those machines are wonderful to look at. I like that idea of Surgical Tubing for the roller. I wonder if 3/8 is the right
                          Message 12 of 12 , Jun 26, 2012
                            --- In midatlanticretro@yahoogroups.com, Mike Loewen <mloewen@...> wrote:
                            >
                            >
                            > I picked up the HP-85 (original model) today. As advertised, it does
                            > absolutely nothing, but that's okay. It came with:


                            That's great! Even non-working, those machines are wonderful to look at.

                            I like that idea of Surgical Tubing for the roller. I wonder if 3/8" is the right size for the roller I need to replace on my HP9825? I'll have to look around for a supplier of Surgical tubing. When describing the surgical proceedure to the clerk, should I say it's for a Roller Transplant?

                            :) Josh
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