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Re: [cosmacelf] Re: 9368's

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  • Paul
    The 9368 as used in the Super Elf also contains the current limiting series resistors. Other hex drivers may not include this feature and thus require external
    Message 1 of 23 , Dec 14, 2006
      The 9368 as used in the Super Elf also contains the current limiting series
      resistors. Other hex drivers may not include this feature and thus require
      external resistors. This was my reason for selecting the 9368. At the time a
      lower cost solution and less PCB space.

      Do a Google search and you will find hundreds of sources for this part
      DM9368N. Not low cost in many cases however. This might work as a group buy
      however where volume makes up for the brokers surcharge.

      Paul

      ----- Original Message -----
      From: "rileym65" <no_reply@yahoogroups.com>
      To: <cosmacelf@yahoogroups.com>
      Sent: Thursday, December 14, 2006 8:13 AM
      Subject: [cosmacelf] Re: 9368's


      > My may 2006 Jameco catalog still listed the 9368, but when I looked
      > online it was not there. But there is another 7 seg hex driver, but
      > not pin compatable. if that is not important, then here is the jameco
      > part number: 241824
      > Mike
      >
      > --- In cosmacelf@yahoogroups.com, "effirlem" <melriffe@...> wrote:
      >>
      >> In an earlier post I mentioned that I used Fairchild 9368s to drive 7
      >> segement leds. Over the past 2-3 days I have been checking with all
      >> my old suppliers and cannot find this chip. Obsolete!!! Does anyone
      >> know of a source or a replacement 7 seg. driver/latch that will output
      >> in Hex.
      >>
      >> TIA
      >> Mel
      >>
      >
      >
      >
      >
      > ========================================================
      > Visit the COSMAC ELF website at http://www.cosmacelf.com
      > Yahoo! Groups Links
      >
      >
      >
    • Lee Hart
      ... No; but we ve discussed this topic before. Alternatives are to program a PAL or a PIC to imitate the 9368. -- Ring the bells that still can ring Forget the
      Message 2 of 23 , Dec 14, 2006
        effirlem wrote:
        > In an earlier post I mentioned that I used Fairchild 9368s to drive 7
        > segement leds. Over the past 2-3 days I have been checking with all
        > my old suppliers and cannot find this chip. Obsolete!!! Does anyone
        > know of a source or a replacement 7 seg. driver/latch that will output
        > in Hex.

        No; but we've discussed this topic before. Alternatives are to program a
        PAL or a PIC to imitate the 9368.

        --
        Ring the bells that still can ring
        Forget the perfect offering
        There is a crack in everything
        That's how the light gets in -- Leonard Cohen
        --
        Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
      • Andrew Wasson
        Hey Mel, As Paul mentioned you can get these guys in large quantity from many suppliers but there doesn t seem to be anywhere you can get them in quantities of
        Message 3 of 23 , Dec 14, 2006
          Hey Mel,
          As Paul mentioned you can get these guys in large quantity from many
          suppliers but there doesn't seem to be anywhere you can get them in
          quantities of one or two for your project.

          We have talked about this a few times and if you want to do a
          workaround you can use eproms, Gals & uControllers.

          If you don't mind doing a workaround, I've posted a schematic and an
          assembler listing and a schematic of a uController design using a
          Parallax SX Chip. It drives 2 - common cathode 7-segment leds. It's in
          the files area in the "Andrew's" Odds and ends folder.

          It should be quite simple to improve upon and use with a Pic or for
          that matter any uController with enough I/O.

          Andrew




          --- In cosmacelf@yahoogroups.com, "effirlem" <melriffe@...> wrote:
          >
          > In an earlier post I mentioned that I used Fairchild 9368s to drive 7
          > segement leds. Over the past 2-3 days I have been checking with all
          > my old suppliers and cannot find this chip. Obsolete!!! Does anyone
          > know of a source or a replacement 7 seg. driver/latch that will output
          > in Hex.
          >
          > TIA
          > Mel
          >
        • Aurel Boisvert
          You could also program a 74S288 ,74S188 or 82S123 to drive the 7 segments leds. You would need a resistor for each led so they have the proper voltage across
          Message 4 of 23 , Dec 14, 2006
            You could also program a 74S288 ,74S188 or 82S123 to drive
            the 7 segments leds. You would need a resistor for each led so they
            have the proper voltage across them.
            Aurel

            ----- Original Message -----
            From: "Lee Hart" <leeahart@...>
            To: <cosmacelf@yahoogroups.com>
            Sent: Thursday, December 14, 2006 2:43 PM
            Subject: Re: [cosmacelf] 9368's


            > effirlem wrote:
            > > In an earlier post I mentioned that I used Fairchild 9368s to drive 7
            > > segement leds. Over the past 2-3 days I have been checking with all
            > > my old suppliers and cannot find this chip. Obsolete!!! Does anyone
            > > know of a source or a replacement 7 seg. driver/latch that will output
            > > in Hex.
            >
            > No; but we've discussed this topic before. Alternatives are to program a
            > PAL or a PIC to imitate the 9368.
            >
            > --
            > Ring the bells that still can ring
            > Forget the perfect offering
            > There is a crack in everything
            > That's how the light gets in -- Leonard Cohen
            > --
            > Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
            >
            >
            >
            > ========================================================
            > Visit the COSMAC ELF website at http://www.cosmacelf.com
            > Yahoo! Groups Links
            >
            >
            >
            >
          • effirlem
            ... lot to chew on and digest. Thanks again. Mel
            Message 5 of 23 , Dec 15, 2006
              ---Thanks to everyone who posted as per my question. That gives me a
              lot to chew on and digest.
              Thanks again.
              Mel
              > >
              > >
              > >
              > > ========================================================
              > > Visit the COSMAC ELF website at http://www.cosmacelf.com
              > > Yahoo! Groups Links
              > >
              > >
              > >
              > >
              >
            • effirlem
              ... Mike, I called Jameco and they could not explain why the 9368s were still listed, but they had no stock. I even talked to Tech support and they could not
              Message 6 of 23 , Dec 15, 2006
                --- In cosmacelf@yahoogroups.com, rileym65 <no_reply@...> wrote:
                >
                > My may 2006 Jameco catalog still listed the 9368, but when I looked
                > online it was not there. But there is another 7 seg hex driver, but
                > not pin compatable. if that is not important, then here is the jameco
                > part number: 241824
                > Mike
                Mike, I called Jameco and they could not explain why the 9368s were
                still listed, but they had no stock. I even talked to Tech support
                and they could not give me a replacement

                #241842...I downloaded the schematic for this chip and it did not look
                as if it would do the job.
                Thanks for your reply.
                > > Mel
                > >
                >
              • Lee Hart
                ... Resistors aren t as big a deal as you might think. The 9368 s ran extremely hot, because LEDs in the good old days needed a lot of current because they
                Message 7 of 23 , Dec 15, 2006
                  Aurel Boisvert wrote:
                  > You could also program a 74S288 ,74S188 or 82S123 to drive
                  > the 7 segments leds. You would need a resistor for each led so they
                  > have the proper voltage across them.

                  Resistors aren't as big a deal as you might think. The 9368's ran
                  extremely hot, because LEDs in the "good old days" needed a lot of
                  current because they weren't very efficient.

                  Modern LEDs are a lot more efficient, so take a lot less current. CMOS
                  ICs automatically have resistive outputs; you can often connect a CMOS
                  output straight to an LED with no resistor at all. Saves a lot parts,
                  and the IC still won't get hot.

                  The old 27C16 EPROM is CMOS, and the easiest chip there is to program.
                  No programmer at all is needed -- you can literally plug it onto a
                  breadboard socket, and use some DIP switches to set the address and data
                  inputs, and a pushbutton to pulse the "program" pin. Three 9v transistor
                  radio batteries provide the programming voltage. If you mess up, UV will
                  erase it and you can try again.

                  --
                  Ring the bells that still can ring
                  Forget the perfect offering
                  There is a crack in everything
                  That's how the light gets in -- Leonard Cohen
                  --
                  Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
                • Lee Hart
                  Hey! I just had an idea! Could be *perfect* for kids, home experimenters, and other hobbyists! 1. You could have a junk box full of every IC you might need...
                  Message 8 of 23 , Dec 15, 2006
                    Hey! I just had an idea! Could be *perfect* for kids, home
                    experimenters, and other hobbyists!

                    1. You could have a junk box full of every IC you might need...
                    but that's expensive, and you never have the right ones anyway.

                    2. You could buy parts every time...
                    but now you have to wait for parts, and shipping and handling
                    charges are way more than the cost of the parts.

                    3. You could have a PAL programmer, and a handful of blank chips...
                    Program them to simulate the digital IC you need (like this
                    binary-to-hex display decoder)... but PAL programmers are
                    expensive, and you pretty much have to be an engineer to figure
                    out how to design the logic and program them.

                    4. A small microcomputer (PIC, Atmel, etc.) can also be programmed
                    to simulate a logic chip, like a PAL...
                    The programmers are cheaper and easier to get than for PALs...
                    But they are far harder to program -- now you need to be not
                    only an engineer but also a programmer to write the software.

                    But what if...

                    Start with a small cheap micro that has built-in EEPROM nonvolatile
                    memory. Write a program that lets it read a couple of pushbuttons and
                    drive a couple LEDs, so a kid can read/write data into that EEPROM
                    without any computer, software, or other "fancy stuff".

                    The kid enters the truth table of the digital IC he wants to simulate.
                    It gets stored in the micro's EEPROM.

                    Now, when you reset the micro, it simply reads the inputs, and uses the
                    EEPROM lookup table to set the outputs accordingly. There will be a
                    "propagation delay" (program execution time), but it's probably
                    comparable to the old 4000 series CMOS anyway.

                    The fun part here is to work out a programming language so simple that
                    kids, experimenters, and other non-computer people will actually start
                    building again.

                    What do you think?
                    --
                    Ring the bells that still can ring
                    Forget the perfect offering
                    There is a crack in everything
                    That's how the light gets in -- Leonard Cohen
                    --
                    Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
                  • Paul
                    The Super Elf 9368 s did not run that hot (warm to touch but not what I consider hot) but I also used a relatively efficient led display. There were no
                    Message 9 of 23 , Dec 15, 2006
                      The Super Elf 9368's did not run that hot (warm to touch but not what I
                      consider hot) but I also used a relatively efficient led display. There were
                      no reported (9368) failures but lots of failed 4xxx parts that failed.

                      I agree that most led displays of the time required a lot of current


                      In any event if you are trying to repair old Super Elf's or just need a
                      couple of parts its worth looking around for old stock.

                      I have some inquiries out to see what I can get them for in Q100. There are
                      thousands available but usually the price is high.

                      Paul


                      ----- Original Message -----
                      From: "Lee Hart" <leeahart@...>
                      To: <cosmacelf@yahoogroups.com>
                      Sent: Friday, December 15, 2006 8:19 AM
                      Subject: Re: [cosmacelf] 9368's


                      > Aurel Boisvert wrote:
                      >> You could also program a 74S288 ,74S188 or 82S123 to drive
                      >> the 7 segments leds. You would need a resistor for each led so they
                      >> have the proper voltage across them.
                      >
                      > Resistors aren't as big a deal as you might think. The 9368's ran
                      > extremely hot, because LEDs in the "good old days" needed a lot of
                      > current because they weren't very efficient.
                      >
                      > Modern LEDs are a lot more efficient, so take a lot less current. CMOS
                      > ICs automatically have resistive outputs; you can often connect a CMOS
                      > output straight to an LED with no resistor at all. Saves a lot parts,
                      > and the IC still won't get hot.
                      >
                      > The old 27C16 EPROM is CMOS, and the easiest chip there is to program.
                      > No programmer at all is needed -- you can literally plug it onto a
                      > breadboard socket, and use some DIP switches to set the address and data
                      > inputs, and a pushbutton to pulse the "program" pin. Three 9v transistor
                      > radio batteries provide the programming voltage. If you mess up, UV will
                      > erase it and you can try again.
                      >
                      > --
                      > Ring the bells that still can ring
                      > Forget the perfect offering
                      > There is a crack in everything
                      > That's how the light gets in -- Leonard Cohen
                      > --
                      > Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
                      >
                      >
                      >
                      > ========================================================
                      > Visit the COSMAC ELF website at http://www.cosmacelf.com
                      > Yahoo! Groups Links
                      >
                      >
                      >
                    • Al W,
                      ... I agree that the 9368 s on the Super Elf don t run all that hot but you may be comparing two different classes of IC s with different
                      Message 10 of 23 , Dec 15, 2006
                        --- In cosmacelf@yahoogroups.com, "Paul" <paulm@...> wrote:
                        >
                        > The Super Elf 9368's did not run that hot (warm to touch but not what I
                        > consider hot) but I also used a relatively efficient led display. There were
                        > no reported (9368) failures but lots of failed 4xxx parts that failed.

                        I agree that the 9368's on the Super Elf don't run all that hot but you may be comparing
                        two different classes of IC's with different probable-causes-of-failure. As far as I
                        remember the 9368 was a TTL component and the 4xxx are CMOS. CMOS logic in general
                        prefers to run cool though chips like the 4049 and 4050 drivers can run a little warm. You
                        must also handle CMOS logic with more care during and after installation.

                        My experiences have been that most CMOS failures are the result of improper handling
                        both before and after installation. Static is the main cause and just slipping an IC into
                        improper foam can generate hundreds of volts which is sufficient to puncture the gate
                        insulation. I quit buying CMOS chips from hamfests some 30 years ago because the
                        moronic vendors would have piles of unprotected chips in boxes.

                        The CMOS equipment is the same way. The two Super Elf's that I own came totally
                        unprotected from hamfest tables. They have been repaired and nowadays I store them in
                        static bags when they aren't being used but many people don't do that. Why do you think
                        that responsible vendors ship this stuff in static bags anyway?

                        Also kit style computers like the Elfs have been assembled with people of wide
                        backgrounds in the past. It is impossible to tell whether proper handlng techniques were
                        used or not but my guess is that many people ignored all the warnings.

                        My experience also shows that a high percentage of kits bought used never worked
                        correctly from the very start so be wary when you buy from eBay as well! A pretty panel
                        dosen't mean a proper assembly was done. This is especially true of Heathkits but other
                        brands as well.

                        al winfrey
                        ....
                      • Paul
                        I do not want to get into a debate about 4000 CMOS vs. TTL. I was commenting about the very hot comment regarding the TTL part where heat can be a factor in
                        Message 11 of 23 , Dec 15, 2006
                          I do not want to get into a debate about 4000 CMOS vs. TTL. I was commenting
                          about the "very hot" comment regarding the TTL part where heat can be a
                          factor in failure and pointing out the application that I designed into the
                          Super Elf. I took the manufacturers requirements into the design and did not
                          use just any LED display. Others apparently were not as careful and ended up
                          with very hot parts.

                          The issue is not properly applying the manufacturers design specifications
                          etc.

                          I was the designer of many CMOS designs beyond the ELF series including some
                          on the Space Telescope.

                          The CMOS (on the ELF) failures we had were usually long after original
                          assembly.

                          Its really very hard to damage a CMOS part even with no protection.

                          Once inserted into the Super Elf board no protection is needed as every
                          input is properly terminated.

                          Sure if you work in 5% humidity and walk across a rug and try to draw a
                          spark you might damage one but its really hard to do unless you are trying.
                          Once the input is terminated as installed in a PCB socket its extremely hard
                          to cause damage.

                          Please do not forget that every gate has internal protection and it takes a
                          lot of energy to cause damage.

                          This does not mean its ok to forget to use reasonable precautions. But what
                          applies to loose parts does not mean its applies to assemblies

                          We had a extremely low return of new kits under warranty. If it was more
                          than 1% we would have lost money.

                          Bent pins and bad soldering was the major cause of any of our kits
                          regardless of the class of IC's used. Couple of times a year we got back a
                          acid core soldered board which was scrapped.

                          NO kit manufacturer can remain in business if the failure rate on assembly
                          is even close to 10% so I take exception to your comment about a high %
                          failure rate. 5% return is doom to a kit manufacturer and who would consider
                          that a HIGH %.

                          Heath Kit failed when the cost of kits became higher than the cost of the
                          equivalent product already assembled and tested; NOT from a high failure
                          rate.

                          I will buy "surplus repackaged" parts of ANY type. The apparent savings
                          rarely pays off in the long run.

                          Paul


                          ----- Original Message -----
                          From: "Al W," <wa9hsl@...>
                          To: <cosmacelf@yahoogroups.com>
                          Sent: Friday, December 15, 2006 4:03 PM
                          Subject: [cosmacelf] Re: 9368's


                          > --- In cosmacelf@yahoogroups.com, "Paul" <paulm@...> wrote:
                          >>
                          >> The Super Elf 9368's did not run that hot (warm to touch but not what I
                          >> consider hot) but I also used a relatively efficient led display. There
                          >> were
                          >> no reported (9368) failures but lots of failed 4xxx parts that failed.
                          >
                          > I agree that the 9368's on the Super Elf don't run all that hot but you
                          > may be comparing
                          > two different classes of IC's with different probable-causes-of-failure.
                          > As far as I
                          > remember the 9368 was a TTL component and the 4xxx are CMOS. CMOS logic in
                          > general
                          > prefers to run cool though chips like the 4049 and 4050 drivers can run a
                          > little warm. You
                          > must also handle CMOS logic with more care during and after installation.
                          >
                          > My experiences have been that most CMOS failures are the result of
                          > improper handling
                          > both before and after installation. Static is the main cause and just
                          > slipping an IC into
                          > improper foam can generate hundreds of volts which is sufficient to
                          > puncture the gate
                          > insulation. I quit buying CMOS chips from hamfests some 30 years ago
                          > because the
                          > moronic vendors would have piles of unprotected chips in boxes.
                          >
                          > The CMOS equipment is the same way. The two Super Elf's that I own came
                          > totally
                          > unprotected from hamfest tables. They have been repaired and nowadays I
                          > store them in
                          > static bags when they aren't being used but many people don't do that. Why
                          > do you think
                          > that responsible vendors ship this stuff in static bags anyway?
                          >
                          > Also kit style computers like the Elfs have been assembled with people of
                          > wide
                          > backgrounds in the past. It is impossible to tell whether proper handlng
                          > techniques were
                          > used or not but my guess is that many people ignored all the warnings.
                          >
                          > My experience also shows that a high percentage of kits bought used never
                          > worked
                          > correctly from the very start so be wary when you buy from eBay as well! A
                          > pretty panel
                          > dosen't mean a proper assembly was done. This is especially true of
                          > Heathkits but other
                          > brands as well.
                          >
                          > al winfrey
                          > ....
                          >
                          >
                          >
                          >
                          >
                          > ========================================================
                          > Visit the COSMAC ELF website at http://www.cosmacelf.com
                          > Yahoo! Groups Links
                          >
                          >
                          >
                        • Paul
                          OOPS left out a critical NOT in the following line Paul ... From: Paul To: Sent: Friday, December 15, 2006
                          Message 12 of 23 , Dec 15, 2006
                            OOPS left out a critical NOT in the following line

                            Paul

                            ----- Original Message -----
                            From: "Paul" <paulm@...>
                            To: <cosmacelf@yahoogroups.com>
                            Sent: Friday, December 15, 2006 7:18 PM
                            Subject: Re: [cosmacelf] Re: 9368's
                            >
                            > I will """NOT""" buy "surplus repackaged" parts of ANY type. The apparent
                            > savings
                            > rarely pays off in the long run.
                            >
                            > Paul
                          • Al W,
                            ... I m not sure what 9368 s have to do with 4xxx logic but from your original note... ... I understand what you are saying but I worked my way through college
                            Message 13 of 23 , Dec 16, 2006
                              --- In cosmacelf@yahoogroups.com, "Paul" <paulm@...> wrote:
                              >
                              > I do not want to get into a debate about 4000 CMOS vs. TTL. I was commenting
                              > about the "very hot" comment regarding the TTL part where heat can be a
                              > factor in failure and pointing out the application that I designed into the
                              > Super Elf. I took the manufacturers requirements into the design and did not
                              > use just any LED display. Others apparently were not as careful and ended up
                              > with very hot parts.
                              >

                              I'm not sure what 9368's have to do with 4xxx logic but from your original note...

                              >> The Super Elf 9368's did not run that hot (warm to touch but not what I
                              >> consider hot) but I also used a relatively efficient led display. There were
                              >> no reported (9368) failures but lots of failed 4xxx parts that failed.

                              I understand what you are saying but I worked my way through college as a technician for
                              a glass production line equipment supplier (we did CMOS) and have not noticed a properly
                              designed 4xxx failure due to self-generated heat. You can make them get hot but they
                              don't usually do that on thier own.

                              As to the static damage, it can many times be detected with a scope long before the part
                              actually fails in circuit. I disagree with your comments on the handling of CMOS chips. I
                              observe the anti-static rules and have very-very few problems with 4xxx parts.

                              As to the Heathkit comments I'm going on what I've found on the used market as I used to
                              buy and sell Heathkit stuff for fun and profit before eBay appeared. I suspect that a high
                              number on non-functional or below performance specification kits are still siting in closets
                              across the country and some get turned loose on eBay as "it powers up but I didn't test it".
                              Buyer beware when you read this because the problem is not just with Heathkits.

                              My Super Elfs have heat problems mainly with the diode voltage reducing chain that feeds
                              the 2/3 three-terminal regulators. The diodes can get pretty hot but they also have other
                              problems because of the very narrow space between holes for the diodes.

                              Diodes aren't usually plated right up to the body of the part and therefore its's hard to get
                              a good solder connection if you push the part all the way to the board. The problem may
                              show up as intermittant displays or "glitches" in operation or simply not working at all.
                              You can spot them pretty quickly visually or with a meter and patience.

                              The cure for intermittant diode connections is to mount the diodes up off of the board and
                              allow more of the plated part of the component lead to contact the plated-through-hole
                              for soldering.

                              al winfrey
                              ....
                            • effirlem
                              ... Steve, thanks for the link. I called and they assured me that while these chips are not the Fairchild 9368, they would do the same job. So, I ordered what
                              Message 14 of 23 , Dec 16, 2006
                                --- In cosmacelf@yahoogroups.com, Steve Valin <sjvalin@...> wrote:
                                >
                                > Mel,
                                >
                                > It looks like Unicorn Electronics has them, although
                                > the description on their site isn't correct. It might
                                > be worth a call.
                                >
                                > http://www.unicornelectronics.com/IC/9000.html
                                >
                                Steve, thanks for the link. I called and they assured me that while
                                these chips are not the Fairchild 9368, they would do the same job.
                                So, I ordered what I needed for my project. When I get them, I will
                                test them and post here giving the results.
                                Mel
                                > >
                                > >
                                >
                                >
                                >
                                >
                                >
                                _____________________________________________________________________
                                _______________
                                > Need a quick answer? Get one in minutes from people who know.
                                > Ask your question on www.Answers.yahoo.com
                                >
                              • Paul
                                I disagree with you but clearly you have your own ideas and keep expanding the subject. My experience is from designing and selling thousands of KITs and also
                                Message 15 of 23 , Dec 16, 2006
                                  I disagree with you but clearly you have your own ideas and keep expanding
                                  the subject. My experience is from designing and selling thousands of KITs
                                  and also designing and managing the eletronics in spacecraft.

                                  I have better things to do.

                                  Paul

                                  ----- Original Message -----
                                  From: "Al W," <wa9hsl@...>
                                  To: <cosmacelf@yahoogroups.com>
                                  Sent: Saturday, December 16, 2006 2:22 AM
                                  Subject: [cosmacelf] Re: 9368's


                                  > --- In cosmacelf@yahoogroups.com, "Paul" <paulm@...> wrote:
                                  >>
                                  >> I do not want to get into a debate about 4000 CMOS vs. TTL. I was
                                  >> commenting
                                  >> about the "very hot" comment regarding the TTL part where heat can be a
                                  >> factor in failure and pointing out the application that I designed into
                                  >> the
                                  >> Super Elf. I took the manufacturers requirements into the design and did
                                  >> not
                                  >> use just any LED display. Others apparently were not as careful and ended
                                  >> up
                                  >> with very hot parts.
                                  >>
                                  >
                                  > I'm not sure what 9368's have to do with 4xxx logic but from your original
                                  > note...
                                  >
                                  >>> The Super Elf 9368's did not run that hot (warm to touch but not what I
                                  >>> consider hot) but I also used a relatively efficient led display. There
                                  >>> were
                                  >>> no reported (9368) failures but lots of failed 4xxx parts that failed.
                                  >
                                  > I understand what you are saying but I worked my way through college as a
                                  > technician for
                                  > a glass production line equipment supplier (we did CMOS) and have not
                                  > noticed a properly
                                  > designed 4xxx failure due to self-generated heat. You can make them get
                                  > hot but they
                                  > don't usually do that on thier own.
                                  >
                                  > As to the static damage, it can many times be detected with a scope long
                                  > before the part
                                  > actually fails in circuit. I disagree with your comments on the handling
                                  > of CMOS chips. I
                                  > observe the anti-static rules and have very-very few problems with 4xxx
                                  > parts.
                                  >
                                  > As to the Heathkit comments I'm going on what I've found on the used
                                  > market as I used to
                                  > buy and sell Heathkit stuff for fun and profit before eBay appeared. I
                                  > suspect that a high
                                  > number on non-functional or below performance specification kits are still
                                  > siting in closets
                                  > across the country and some get turned loose on eBay as "it powers up but
                                  > I didn't test it".
                                  > Buyer beware when you read this because the problem is not just with
                                  > Heathkits.
                                  >
                                  > My Super Elfs have heat problems mainly with the diode voltage reducing
                                  > chain that feeds
                                  > the 2/3 three-terminal regulators. The diodes can get pretty hot but they
                                  > also have other
                                  > problems because of the very narrow space between holes for the diodes.
                                  >
                                  > Diodes aren't usually plated right up to the body of the part and
                                  > therefore its's hard to get
                                  > a good solder connection if you push the part all the way to the board.
                                  > The problem may
                                  > show up as intermittant displays or "glitches" in operation or simply not
                                  > working at all.
                                  > You can spot them pretty quickly visually or with a meter and patience.
                                  >
                                  > The cure for intermittant diode connections is to mount the diodes up off
                                  > of the board and
                                  > allow more of the plated part of the component lead to contact the
                                  > plated-through-hole
                                  > for soldering.
                                  >
                                  > al winfrey
                                  > ....
                                  >
                                  >
                                  >
                                  > ========================================================
                                  > Visit the COSMAC ELF website at http://www.cosmacelf.com
                                  > Yahoo! Groups Links
                                  >
                                  >
                                  >
                                • effirlem
                                  Steve and others who are interested. I received the 9368s from Unicorn Elec. yesterday. I set one up on a bread board, driving a 7 segement LED. It works,
                                  Message 16 of 23 , Dec 21, 2006
                                    Steve and others who are interested. I received the "9368s" from
                                    Unicorn Elec. yesterday. I set one up on a bread board, driving a 7
                                    segement LED. It works, "0" thru "F", pin for pin compatible.
                                    Thanks for giving me the link
                                    Mel
                                  • eight_bit_jdrose
                                    I did not realize that. Excellent tip.
                                    Message 17 of 23 , Jul 17, 2012
                                      I did not realize that. Excellent tip.

                                      >
                                      > > Diodes aren't usually plated right up to the body of the part and
                                      > > therefore its's hard to get
                                      > > a good solder connection if you push the part all the way to the board.
                                      > > The problem may
                                      > > show up as intermittant displays or "glitches" in operation or simply not
                                      > > working at all.
                                      > > You can spot them pretty quickly visually or with a meter and patience.
                                      > >
                                      > > The cure for intermittant diode connections is to mount the diodes up off
                                      > > of the board and
                                      > > allow more of the plated part of the component lead to contact the
                                      > > plated-through-hole
                                      > > for soldering.
                                      > >
                                      > > al winfrey
                                      > > ....
                                      > >
                                      > >
                                      > >
                                      > > ========================================================
                                      > > Visit the COSMAC ELF website at http://www.cosmacelf.com
                                      > > Yahoo! Groups Links
                                      > >
                                      > >
                                      > >
                                      >
                                    • Lee Hart
                                      ... With LEDs, you will also have problems with intermittents *inside* the LED package if you push them right against the board. The requirements for an
                                      Message 18 of 23 , Jul 17, 2012
                                        > Diodes aren't usually plated right up to the body of the part and
                                        > therefore its hard to get a good solder connection if you push the
                                        > part all the way to the board.

                                        With LEDs, you will also have problems with intermittents *inside* the
                                        LED package if you push them right against the board. The requirements
                                        for an optically clear plastic conflict with the requirements for good
                                        heat resistance for soldering. Heating the lead close to the package can
                                        cause heat stress that breaks the bond wire between the lead and end of
                                        the LED chip.

                                        --
                                        If we knew what we were doing, it wouldn't be called research, would it?
                                        -- Albert Einstein
                                        --
                                        Lee A. Hart http://www.sunrise-ev.com/LeesEVs leeahart@...
                                      • joshbensadon
                                        ... I recently made the mistake of soldering a transistor from 1974 without using a heat sink on the leads. It popped 10 seconds after I turned on the
                                        Message 19 of 23 , Jul 17, 2012
                                          --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
                                          > heat resistance for soldering. Heating the lead close to the package can
                                          > cause heat stress that breaks the bond wire between the lead and end of
                                          > the LED chip.

                                          I recently made the mistake of soldering a transistor from 1974 without using a heat sink on the leads. It popped 10 seconds after I turned on the machine!

                                          I've taken for granted how new semiconductors can sustain heat stress for several seconds.

                                          Hope you don't make the same mistake.
                                          Josh
                                        • Lee Hart
                                          ... Yes indeedy! Also remember the early 4000-series parts were much more static sensitive and had much wider variations in input and output characteristics.
                                          Message 20 of 23 , Jul 17, 2012
                                            joshbensadon wrote:
                                            > I've taken for granted how new semiconductors can sustain heat stress for several seconds.

                                            Yes indeedy!

                                            Also remember the early 4000-series parts were much more static
                                            sensitive and had much wider variations in input and output
                                            characteristics. RCA didn't know much about designing CMOS at the time.
                                            But they learned! It didn't take long for the -B series to come out to
                                            fix these issues.

                                            Now we take it for granted that all CMOS parts are B-series. But if you
                                            get some old parts, beware! They might *not* be!

                                            Analog Devices Inc. is good about researching semiconductor packaging,
                                            and has written many great reports on it. If you want to learn more
                                            about the problems with IC packages that most hobbyists ignore, see...

                                            http://www.analog.com/static/imported-files/quality_assurance/Package_Reliability.pdf.
                                            --
                                            I do not waste my life in friction when it could be turned into
                                            momentum. -- Frances Willard
                                            --
                                            Lee A. Hart http://www.sunrise-ev.com/LeesEVs leeahart@...
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