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Re: [midatlanticretro] 82S141 PROMs

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  • Mike Loewen
    ... I received six National 74S474 PROMs from Unicorn Electronics, and discovered that three of them were not blank (on my Data I/O 29B). Is this a common
    Message 1 of 7 , Feb 13, 2012
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      On Fri, 27 Jan 2012, Mike Loewen wrote:

      > I'm looking for a source for at least six Signetics 82S141 Bi-polar
      > PROMs for my HP project. Common substitutes are National 74S474, MMI
      > 6341-1, TI 28S46, Harris 7641-5, AMD 27S31. Best price I've found so far
      > is $12 a piece at hobbyroms.com. I was faked out by a false lead at
      > electronicplus.com - they don't have any left.
      >
      > Any ideas on sources? My Data I/O 29B should be able to handle them.

      I received six National 74S474 PROMs from Unicorn Electronics, and
      discovered that three of them were not blank (on my Data I/O 29B). Is
      this a common occurrence for old stock?


      Mike Loewen mloewen@...
      Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
    • Dave McGuire
      ... That s pretty rare; these guys usually know about OTP devices. Unicorn will probably swap them out. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
      Message 2 of 7 , Feb 13, 2012
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        On 02/13/2012 10:54 PM, Mike Loewen wrote:
        > I received six National 74S474 PROMs from Unicorn Electronics, and
        > discovered that three of them were not blank (on my Data I/O 29B). Is
        > this a common occurrence for old stock?

        That's pretty rare; these guys usually know about OTP devices.
        Unicorn will probably swap them out.

        -Dave

        --
        Dave McGuire, AK4HZ
        New Kensington, PA
      • Mike
        Mike, I ve encountered burned bi-polar PROMs sold as new only once, and the seller refunded my money, so it wasn t a big problem. arcadechips.com has
        Message 3 of 7 , Feb 14, 2012
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          Mike,

          I've encountered burned bi-polar PROMs sold as "new" only once, and the seller refunded my money, so it wasn't a big problem.

          arcadechips.com has excellent prices for proms, including a good selection of bi-polar varieties.

          Regards,
          Mike Willegal

          --- In midatlanticretro@yahoogroups.com, Mike Loewen <mloewen@...> wrote:
          >
          > On Fri, 27 Jan 2012, Mike Loewen wrote:
          >
          > > I'm looking for a source for at least six Signetics 82S141 Bi-polar
          > > PROMs for my HP project. Common substitutes are National 74S474, MMI
          > > 6341-1, TI 28S46, Harris 7641-5, AMD 27S31. Best price I've found so far
          > > is $12 a piece at hobbyroms.com. I was faked out by a false lead at
          > > electronicplus.com - they don't have any left.
          > >
          > > Any ideas on sources? My Data I/O 29B should be able to handle them.
          >
          > I received six National 74S474 PROMs from Unicorn Electronics, and
          > discovered that three of them were not blank (on my Data I/O 29B). Is
          > this a common occurrence for old stock?
          >
          >
          > Mike Loewen mloewen@...
          > Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
          >
        • dfnr2
          Hi Mike, I think it is common. I think a lot of these parts were ordered pre-programmed at the factory, so a lot of New old-stock parts may actually be
          Message 4 of 7 , Feb 14, 2012
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            Hi Mike,

            I think it is common. I think a lot of these parts were ordered pre-programmed at the factory, so a lot of "New" old-stock parts may actually be programmed, and it would be difficult for a distributor to tell without actually testing.

            For what it's worth, I hadn't heard of Unicorn at that time, and by now, I have bought a number of parts from them, and have found their service and their parts to be excellent. I would definitely call them if your part it pre-programmed.

            A while back, I repaired an Asteroids Deluxe board, and I bought several 74S287 and 82S129 proms from one mail order company and Fry's, and found them all to be pre-programmed. At first I thought I was doing something wrong. Here's the thread:

            http://groups.google.com/group/rec.games.video.arcade.collecting/browse_thread/thread/f9b9c721a8130baa/8281bfdf48f56808?q=#8281bfdf48f56808

            I finally got a couple of blank PROMS from a vintage arcade parts seller online.

            BTW, here's my repair log for that board:

            http://groups.google.com/group/rec.games.video.arcade.collecting/browse_thread/thread/9e7c79a72ed8a8af/673211fb622143f1


            Dave
          • Mike Loewen
            ... Thanks, Mike, I found arcadechips.com last night and he supposedly has them in stock. I left a message, asking about them, as well as one for Unicorn.
            Message 5 of 7 , Feb 14, 2012
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              On Tue, 14 Feb 2012, Mike wrote:

              > I've encountered burned bi-polar PROMs sold as "new" only once, and the seller refunded my money, so it wasn't a big problem.
              >
              > arcadechips.com has excellent prices for proms, including a good selection of bi-polar varieties.
              >
              > Regards,
              > Mike Willegal

              Thanks, Mike, I found arcadechips.com last night and he supposedly has
              them in stock. I left a message, asking about them, as well as one for
              Unicorn.


              Mike Loewen mloewen@...
              Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
            • Mike Loewen
              Just to be on the safe side, I ran through the complete voltage and performance checks for the Data I/O 29B and UniPak2B. All voltages and waveforms were well
              Message 6 of 7 , Feb 16, 2012
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                Just to be on the safe side, I ran through the complete voltage and
                performance checks for the Data I/O 29B and UniPak2B. All voltages and
                waveforms were well within spec. I felt like a lab weenie, again. :-)


                Mike Loewen mloewen@...
                Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
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