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486 Overdrive no boot

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  • DonutKing
    replied
    Thanks heaps I really appreciate it
    Happy to help out with any 'pickup only' auctions if you need it.

    Leave a comment:


  • Neon_WA
    replied
    Originally posted by DonutKing View Post
    That Asus board could be the go, what sort of price were you after?
    Just shipping will do once you have the board & happy with it
    PM me a mailing address.

    Would just like to have someone in your region just in case something comes up on ebay that the seller wont ship.

    took some pics for you http://www.flickr.com/photos/neon_wa...7626409255902/
    Last edited by Neon_WA; April 1, 2011, 07:04 PM.

    Leave a comment:


  • DonutKing
    replied
    That Asus board could be the go, what sort of price were you after?

    Leave a comment:


  • Neon_WA
    replied
    I will just keep editing this post as I go thru and find ones in my boxes of boards

    first one probably wont suit u
    Aopen VI15G
    http://www.stason.org/TULARC/pc/moth...486-VI15G.html
    http://motherboards.mbarron.net/mode...lb3/vi15g.html

    2nd is probably a lost cause to find info on
    IPEX VL486 Rev 2.0 IPX-UM-486IV6201
    4 banks (8 slots) of 30-pin
    4 x 32 ISA
    2 x VESA
    UMC 82481 / 482 chipset
    20 - 50 FSB
    no jumpers for CPU type
    similar layout to this (minus one ISA slot) http://stason.org/TULARC/pc/motherbo...00A-P-VLB.html

    3rd one is probably a good one for you
    ASUS VL/I-486SVGO Rev 1.2
    almost identical this board in layout & specs, but has 2 x 72-pin & 2 banks (4 slots) of 30-pin
    http://stason.org/TULARC/pc/motherbo...SV2G-VL-I.html
    Last edited by Neon_WA; March 31, 2011, 11:03 PM.

    Leave a comment:


  • DonutKing
    replied
    Either 30 pin or 72 pin memory slots is fine. I have plenty of spare SIMMs, both parity or non-parity.
    Not worried about 20MHz bus, doubt I'd ever use it.
    Cheers

    Leave a comment:


  • Neon_WA
    replied
    just so I can narrow down the selection.. what pin memory slots & do you need 20FSB

    Leave a comment:


  • DonutKing
    replied
    Thanks for the offer, I appreciate it. I'm basically after a board with 2x VLB slots. I have some spare 15ns cache chips so it doesn't matter if it has empty cache sockets. Support for 3.3V CPU's would be nice but not a necessity since I have 2 5V DX4 Overdrives.

    I have a spare socket 3 board but its a PC-Chips M912 with fake cache chips soldered to the board, and it seems a bit unstable once it warms up. Good for testing but thats about it.

    Leave a comment:


  • Neon_WA
    replied
    Originally posted by DonutKing View Post
    unfortunately 486 motherboards are pretty scarce over here, and they fetch outrageous prices on ebay...
    Let me know what exactly you are chasing and I will look thru the 40+ 486 boards I have squirreled away.

    Leave a comment:


  • Agent Orange
    replied
    Looks like decent system. I like your video card choice. The biggest problem I have with the 486's is that I expect too much. After a hour or so playing HAWX on the 'big machine' you naturally expect the poor 'ol 486 to do back flips. Let us know if make any progress with the POD.

    Leave a comment:


  • DonutKing
    replied
    Video card is a VLB ET4000W32/P with 2MB video memory- brand is 'Hercules Dynamite'.

    The rest of the system specs:
    CT2800 Vibra 16, with XR385 DB
    Gravis Ultrasound Classic 3.4 with 1MB memory
    4x 4MB 70ns FPM 30-pin SIMMs
    Winbond VLB I/O controller card
    Quantum 1280AT HDD, with Ontrack DDO


    Doom runs perfectly fine even with sound enabled (using the GUS). I'm running timedemo with no sound and one slot less than max screen size (so the status bar is visible). Hexen can get a little choppy particularly when smashing glass windows but apart from that its very playable.

    Leave a comment:


  • Agent Orange
    replied
    Originally posted by DonutKing View Post
    Unfortunately that seller won't ship outside the US, otherwise I'd snap that up in a heartbeat.

    The other guy ships worldwide but I don't particularly feel like paying triple the price :/

    Anyway, I tried overclocking the AMD DX4 to 120MHz with some interesting results.

    It was not stable at 40MHz bus speed without introducing some wait states. Even thoguh I set the bus speed to 40MHz the BIOS detected the processor as 133MHz. There are no options for multiplier on the motherboard, just bus speed. Sysinfo even agreed that the processor is running at 133MHz. Not sure whats going on there, I'm assuming the BIOS doesn't have an entry in its CPU table for 120MHz. CACHECHK reports 120MHz.

    going from 100MHz to 120MHz increased my 3dbench score from 66.6 to 71.4 However, DOOM timedemo 3 went from 41 to 38 - The additional wait states seem to be more of a hindrance than the benefit gained by the extra bus and CPU speed. Likewise, PCPBench mode 101 (640x480) also went from 6.8 at 100MHz to 6.5 at 120MHz. This is with 15ns L2 cache and 70 nanosecond fast-page memory.

    At the moment I think I'm better off just running at 100MHz, not much sense in accelerating this Am486DX4's already shortened lifespan for little practical benefit :P
    Late edit: Find someone to throw in with yourself and make that guy an offer he can't refuse. Tell him you'll take 6 or 8. You can contact him through eBay.
    Not bad numbers. What's your video card? When running DOOM how does it look - any jerking or stuttering?

    Leave a comment:


  • DonutKing
    replied
    Unfortunately that seller won't ship outside the US, otherwise I'd snap that up in a heartbeat.

    The other guy ships worldwide but I don't particularly feel like paying triple the price :/

    Anyway, I tried overclocking the AMD DX4 to 120MHz with some interesting results.

    It was not stable at 40MHz bus speed without introducing some wait states. Even thoguh I set the bus speed to 40MHz the BIOS detected the processor as 133MHz. There are no options for multiplier on the motherboard, just bus speed. Sysinfo even agreed that the processor is running at 133MHz. Not sure whats going on there, I'm assuming the BIOS doesn't have an entry in its CPU table for 120MHz. CACHECHK reports 120MHz.

    going from 100MHz to 120MHz increased my 3dbench score from 66.6 to 71.4 However, DOOM timedemo 3 went from 41 to 38 - The additional wait states seem to be more of a hindrance than the benefit gained by the extra bus and CPU speed. Likewise, PCPBench mode 101 (640x480) also went from 6.8 at 100MHz to 6.5 at 120MHz. This is with 15ns L2 cache and 70 nanosecond fast-page memory.

    At the moment I think I'm better off just running at 100MHz, not much sense in accelerating this Am486DX4's already shortened lifespan for little practical benefit :P
    Last edited by DonutKing; March 30, 2011, 02:23 AM.

    Leave a comment:


  • Agent Orange
    replied
    Looks like you're on the right track. I have my favorite 486 mobo (486-PVT-IO) running an AM586x133 oc'd to 150 Mhz w/ 128 mb total RAM. Check this link: http://computers.shop.ebay.com/?_fro...O&_sacat=58058

    I bought this mobo from this very vendor back last fall. It was like opening a time capsule - everything was there, cables, manual, the whole 9 yards. The price is rediculously low (I thought) for NIB classic 486. The kicker is look what that other yo-yo underneath is trying to sell for 6 time as much and its only a refurb! The shipping may be worth it to you in the long run. Heck, get a few of them at the current going price and you could be the big wheeler-dealer down there in Australia. Keep us infrormed and best of luck.

    Leave a comment:


  • DonutKing
    replied
    unfortunately 486 motherboards are pretty scarce over here, and they fetch outrageous prices on ebay...

    Here is something interesting:

    I took the plunge and put in an AMD DX4-100, which clearly had 3 VOLT written on the surface.
    Stuck a heatsink/fan on it, didn't change any jumpers from the 486DX2 setting, and fired it up.

    It booted first go, at maximum performance settings. Didn't need to change a thing and it worked fine.

    Intrigued, I pulled out the AMD DX4 and put in an Intel DX4- a standard 3 volt one, not an Overdrive.
    The same problems I had with the overdrives occurred.

    Interestingly, the AMD chip was picked up by the BIOS as an 80486DX2 while the Intel chip was detected as a DX4-S. Both were picked up at 100MHz. I confirmed this with cachechk and sysinfo.

    The AMD DX4 only has 8KB L1 cache while the Intel DX4 has 16KB. I presume this is part of the issue- perhaps my board has trouble with CPU's with 16kb of L1 cache?
    It's very odd.

    I'm not sure how long the AMD DX4 will last running at 5V but I'll see how it goes... with the heatsink/fan on there it doesn't get very hot at all (certainly much colder than a DX2 with no fan). I have a few spares anyway, and if the chip smokes I'll just put the DX2 back in. I left it running PCPBENCH for about half an hour yesterday and it was very stable, and the heatsink barely got warm.

    Although the CPU socket is clearly labeled "Socket 3" as far as I can tell it only supports 5V CPUs. Wikipedia seems to think that Socket 3 always supports 3.3V/5V but this board has no jumpers to switch between voltages, and there is definitely no voltage regulator on the board that I can see.

    Interestingly, I found this page: http://www.pcguide.com/ref/cpu/fam/g4I486DX4-c.html
    Which suggests that the 8KB AMD DX4's can handle taking 5V.... whether its true or not, I guess I'll find out soon enough :P

    Leave a comment:


  • Agent Orange
    replied
    Originally posted by DonutKing View Post
    Hmmm. I have managed to get the Pentium Overdrive and the DX4 Overdrive to work, by changing the jumpers on the board to 128kb.

    I have swapped the 20ns cache chips with 15ns chips off a dead board but this doesn't seem to help... if the jumpers are set to 256kb and a DX4/POD is installed, it will hang at the end of the first POST screen.

    Even with 128kb, and the new cache chips, the system is unstable at the fastest wait states/burst settings. However, a DX2-66 works perfectly at these settings.

    I've been fiddling for a while but haven't quite found a stable combination.
    I wonder if there is some limitation of this board or chipset, that if an overdrive is installed you are limited to 128kb or certain minimum RAM/cache wait states.

    EDIT: after a couple of hours of fiddling and being unable to find any stable settings (system would hang when trying to boot DOS, or initialise the sound card, or give EMM386 errors when running programs) I've put the DX2-66 back in, set everything up for max performance, and the full 256kb cache, and its working fine without issue.
    I might fiddle around tomorrow but it seems that the overdrives are off limits
    What I know for sure is the the POD is fickle beast. I have two 486 mobo's that are capable of running just about any Intel/AMD 486 combination, but will not tolerate a POD. The POD compatiblity issues are fairly well known and go to the heart of your system. It requires that you expertly tweak your BIOS with respect to caches, etc. I will not attempt another POD install until I am 100% certain that the mobo will support it. I know that this is not helping your present situation, but I would like to pass on my not so successful experiences with the POD. The POD will, in fact, post on two of my 486 mobo's , but is unstable and the data is often corrupt. On the other hand, this forum is loaded with folks that swear by the POD. You may want to look for a mobo with better documentation and a little more in the main stream.

    Leave a comment:

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