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Re: [midatlanticretro] 82S141 PROMs

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  • 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 1 of 7 , Feb 13 11:50 PM
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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 2 of 7 , Feb 14 8:54 AM
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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 3 of 7 , Feb 14 9:04 AM
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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 4 of 7 , Feb 14 10:31 AM
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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 5 of 7 , Feb 16 7:47 PM
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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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