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Thread: Everex ev-18108 motherboard

  1. #11
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    Quote Originally Posted by jh1523 View Post
    Not necessarily. Many everex 386 boards have the CPU and base RAM on a CPU/memory card - with the CPU soldered on. And there is at least another everex 386 board that came with CPUs in 2 speed variants and they were soldered on: http://bk0010.narod.ru/hardware_specs/m/E-H/30520.htm

    That's a 386SX. The situation is reversed with those. It's shocking to find one that ISN'T soldered on as the CPU is a 100 pin PQFP and is designed for surface mount soldering.

    Of course there is always an exception, as my current hobby machine is a Zenith 386SX16 with the CPU in a strange little AMP socket.

    Typically the only boards I've seen unsoldered 386SX chips on are 1988-89 vintage.

    Quote Originally Posted by Terry Yager View Post
    From the marketing standpoint, it might be perceived to be more profitable to force the user to replace the entire mainboard in order to upgrade.

    --T
    Yeah, but one would expect that primarily in low-end boards like the 386SX. The 386DX was pretty high-end at the time. If that were still the case we might be seeing lots of CoreQuad BGAs surface mounted sans 775LGA socket today, rather than low end stuff like the Celeron and Atom.

    Quote Originally Posted by Chuck(G) View Post
    386SX chips, like 486SX chips were invariably soldered in--their raison d'etre being cheapness.
    Are you sure that you aren't thinking of the i486SL? I've never seen a soldered in 486SX. The 486SL was a surface mount piece PQFP 132. Used in low end motherboards and laptops. I've seen 486SL chips soldered onto a carrier to be used in a socket on some low end motherboards.
    Last edited by dpatten; January 28th, 2009 at 05:44 AM. Reason: spelling, punctuation.

  2. #12
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    Quote Originally Posted by dpatten View Post
    Are you sure that you aren't thinking of the i486SL? I've never seen a soldered in 486SX. The 486SL was a surface mount piece PQFP 132. Used in low end motherboards and laptops. I've seen 486SL chips soldered onto a carrier to be used in a socket on some low end motherboards.
    Quite right--it was the 486SL. The 486SX was another sort of insanity on the part of Intel--sell a 486 with disabled NDP and then sell what amounts to a completely functional 486DX as a 487SX to put the onboard 486SX permanently to sleep.

    Not to hijack the thread, but just a point of curiosity. Many 386DX boards allowed for installation of a Weitek numeric coprocessor in lieu of a 387. Does anyone own such a beast with the Weitek chip? I've never seen a 386DX board with the Weitek installed.

  3. #13
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    The Weitek 3167 was pretty high-end stuff itself, and IIRC costed several times more than a 386DX. I think it plugged straight into the 387 socket. Few people would afford or need them, unless they were using intensive CAD programs and such. Than's why they are pretty rare.

    I have been occasionally searching the fleabay for a 3167, but have never seen one for sale. There are regularly 3170s and 3172s for sale since Sun apparently was more liberal with adding FPUs to its SparcStations.

  4. #14
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    IIRC, the Weitek socket is different from the 387, and some boards even have both (although only one or the other can be installed at a time). I personally have never seen one in the wild.

    --T
    Teach your children how to think, not what, and hold 'em close, not tight.
    _____________________________________________

    Please visit the Vintage-Computer Wiki. Contributers welcome.

  5. #15
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    Default Weitek 4167

    Digging through my parts bin(s), I dug up a Weitek 4167-33. Unfortunately, I don't have a motherboard for it. If anyone happens to stumble across one...
    patscc

  6. #16

    Question

    I have this motherboard too but some questions:

    1. What kind of external CMOS battery should I use for it? (Red arrows)
    2. What's the Instep socket? (Magenta arrow)
    3. What's the 512K jumper? (Yellow arrow)
    4. Any BIOS upgrade for it?
    5. Possible to put a faster CPU >33MHz on it?

    https://stason.org/TULARC/pc/motherb...GATE-ARRA.html


  7. #17
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    1. Battery is usually a 3.6/4.5v NiCD/NiMH. You can use regular alkaline AA cells in a holder if you use a blocking diode since motherboards of the time usually charged the CMOS battery. You can confirm this by powering the board and measuring the pins with a multimeter, just don't short them.

    2. No idea what the socket is for.

    3. Since there's also a 256k jumper next to the socket you pointed out, it's probably to select the amount of system memory installed.

    4. Again no idea.

    5. If the CPU and the associated 66 MHz crystal are socketed, you can attempt to put a faster CPU in. You'll just need a crystal that's double the speed of the CPU you install, so a 40 MHz 386 would need an 80 MHz crystal.

    But unless you have the proprietary memory board that probably goes in the ISA looking slot below the CPU cache chips, that motherboard isn't going to function. The cache chips had me thrown for a loop wondering why it had 160k of cache until I realized it probably uses the 5th 32k chip as a parity module.

  8. #18

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    Quote Originally Posted by GiGaBiTe View Post
    1. Battery is usually a 3.6/4.5v NiCD/NiMH. You can use regular alkaline AA cells in a holder if you use a blocking diode since motherboards of the time usually charged the CMOS battery. You can confirm this by powering the board and measuring the pins with a multimeter, just don't short them.

    2. No idea what the socket is for.

    3. Since there's also a 256k jumper next to the socket you pointed out, it's probably to select the amount of system memory installed.

    4. Again no idea.

    5. If the CPU and the associated 66 MHz crystal are socketed, you can attempt to put a faster CPU in. You'll just need a crystal that's double the speed of the CPU you install, so a 40 MHz 386 would need an 80 MHz crystal.

    But unless you have the proprietary memory board that probably goes in the ISA looking slot below the CPU cache chips, that motherboard isn't going to function. The cache chips had me thrown for a loop wondering why it had 160k of cache until I realized it probably uses the 5th 32k chip as a parity module.
    3. The system memory should be at least 1MB. Maybe it's for the 512/640K base memory but it has an option for it in the BIOS.

    5. Won't 80MHz crystal conflict with the ISA bus speed? With 66MHz, ISA works at 33/4=8.25MHz

    Yes, the 5th chip is for the parity or maybe write-back cache.

  9. #19
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    Quote Originally Posted by RiP2 View Post
    1. What kind of external CMOS battery should I use for it? (Red arrows)
    The battery connector looks like the standard one used for a 6V lithium battery. If so, the options at [here], for an IBM AT, should be applicable.

    Quote Originally Posted by RiP2 View Post
    2. What's the Instep socket? (Magenta arrow)
    From an infoWord magazine, "InSTEP" is a trademark of Everex.
    At [here], an "instep board" is shown in the Connections section, with the board appearing to be a form of CPU upgrade.
    Do an Internet search using: everex instep 486

  10. #20
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    If you don't have the memory board for this thing, as Gigabite mentioned, it's useless. There's no planar base memory without it.

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