Re: EISA board won't post. EISA-486a REV. 1.1

Posted on 2021-05-07, 16:57

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Revision 2.3 and 3.0 of this mainboard have only one oscillator (plus thr 14.31 MHz one). The second one on Rev. 1.1 could be used for having the NPU run at a different frequency than the CPU´s.

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Re: EISA board won't post. EISA-486a REV. 1.1

Posted on 2021-05-06, 18:07

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

As long as you have populated 128KB of L2 Cache and jumpered it for 256KB, the board will not post.

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Re: ASUS Radeon 9800XT : Can I save its life ?

Posted on 2021-05-05, 05:55

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Did you check all 11 8-pin MOSFETS on the top side and the one on the backside? I think some are in VRM circuits and some are just for switching between Molex<->AGP power supply.

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Re: Help (re)building a 486

Posted on 2021-05-03, 09:31

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

ESCOM also used special (crippled) FIC mainboards like the "486 VIP-IO" without the VLB slots, which correctly must have been called "486 IP-IO". I would not be surprised if companies like ESCOM, VOBIS bought differently (wrong) labeled mainboards just so save a few $$.

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Re: Help (re)building a 486

Posted on 2021-05-03, 06:18

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes there are differences between FIC´s "486 VC-HD" and "486 HC-HD". On the VC-HD you can install either an additional numeric processor besides the onboard CPU or a different CPU in the same 86/87 socket. There´s also a socket for a second oscillator if CPU and NPU are supposed to run at different …

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Re: 486 DX @8Mhz FIC 486GVT-2 hidden fsb jumper setting

Posted on 2021-05-02, 17:55

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Don´t worry, you´re not going to damage anything here. 1. CPU core voltage is correctly set to 5V 2. FSB / CPU frequency are far below the nominal values so you are underclocking your CPU.

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Re: Help troubleshoot 486 motherboard

Posted on 2021-05-02, 06:34

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sounds like a memory issue. In most cases you have to populate 4 memory slots with 4 identical RAM sticks starting with Bank 0 (in this case the one closer to the ISA slots). Is there any documentation stating otherwise for this chipset?

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Re: VRM 5v 3.3v

Posted on 2021-05-01, 15:19

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You can use this schematic, but you will have to adapt the pinout. First you must measure the voltages of your 20-pin connector. 1. Remove the jumper block and the CPU 2. turn on the machine 3. measure with a voltmeter between ground and the pins to determine which ones are the 5V input pins 4. …

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Re: VRM 5v 3.3v

Posted on 2021-05-01, 13:06

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well that´s 10 jumpers = a jumper block. Most of them are connecting 5v to the CPU socket some are ground connectors. Finding the original (proprietary) VRM will be quite a challange. A DIY VRM is an option if you can handle a soldering iron well. The easiest way would probably be using an …

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Re: VRM 5v 3.3v

Posted on 2021-05-01, 10:55

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I doubt it´s just a jumper with 2 pins. Any VRM will need a ground connection also. For lower resistance at higher currents there are multiple pins for input and output in many cases. Do you have a picture available?

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Re: FIC 386SC - unusual behaviour with ISA POST diagnostic card

Posted on 2021-04-30, 05:49

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Mine is also the "A2" revision. Here´s my (working) jumpering for 128K. Maybe you can spot a pattern... Filename 128K_jump.JPG File size 1.61 MiB Views 182 views

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Re: What´s wrong with this FIC 486 PAK-3 ??

Posted on 2021-04-29, 13:16

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

O.k., this seems to be CPU dependant. 1.) Intel 486SX -> the system won´t boot from floppy, CPU detected correctly 2.) Intel 486 DX2-50, Intel 486 DX2-66, AMD Am486 DX2-66 all detected correctly and all are extremely slow at 14.5 points in Sysinfo. 3.) AMD Am 486 DX4-100 falsely detected al DX2-100, …

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Re: What´s wrong with this FIC 486 PAK-3 ??

Posted on 2021-04-29, 08:29

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I found a picture of the frontpanel on the net, there´s no hardware turbo switch, just "power" and "power management". The latter being some energy saving feature I suppose. Edit: In BIOS there are several options under "Power Management", also for slowing down or halting the CPU, but those are all …

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What´s wrong with this FIC 486 PAK-3 ??

Posted on 2021-04-29, 08:10

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Currently I´m testing an old FIC 486-PAK-3 mainboard that was used in AT&T´s Globalyst 520. I updated it´s BIOS from 1.00 to 1.06 (from the NEC´s website). It´s now equipped with 64 MB of EDO memory and a 486 DX2-66 CPU. This CPU is correctly detected and identified by the BIOS. The proprietary L2 …

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Re: Mystery “Super-286” motherboard from 1994

Posted on 2021-04-28, 18:26

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Overclocking the CPU and putting a fat sticker on it to decrease cooling instead of using a small cooler, while writing "warranty void if torn" on it - this MUST be PC-Chips.

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Re: Dual Slot 1/Socket 7

Posted on 2021-04-25, 15:52

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ah, I see what you mean. The MCH is sitting on the CPU cards here. This had to be done because they changed platforms between the versions demanding different MCHs. Solutions like American Megatrends "Goliath" with two CPU cards and one memory card had the MCH on the motherboard - but this was (quad …

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Re: Dual Slot 1/Socket 7

Posted on 2021-04-25, 10:44

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Mainboards with CPU-cards and even memory-cards were not unusual in these days. Especially in the enterprise / server segment. I still have one P65UP5 in my collection together with 2 Pentium Pro cards and the Socket 7 card. I never managed to find the Slot 1 card at a decent price.

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Re: VESA feature connector devices

Posted on 2021-04-25, 08:45

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by majestyk

in Marvin \ Video

in Marvin \ Video

Yes. Video Blaster ISA. There were several standards. EGA and then VGA. I believe the VGA edge is compatible to the 26pin one. Datasheets mention 80-pin VAFC (VESA Advanced Feature Connector) with 16bit interface but none of my cards has one. Here´s an example of an 80-pin VAFC connector on a FIC …

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Re: Strange Floppy Disk behaviour 486

Posted on 2021-04-24, 15:36

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Have you done the initial EISA setup for this mainboard using the EISA utility, installed the .cfg / .ovl files for this mainboard? Maybe there is some old configuration still stored in the DALLAS NVRAM. Some mainbords demand even regular ISA cards to be configured with the EISA utility. After …

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Re: Can a VLB contact be replaced?

Posted on 2021-04-24, 12:20

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

While at it I used the remaining PCI-socket to replace one of the VLB sockets on the donor riser-card. And still there are 6 contact left for future cases. Filename VLB_riser.JPG File size 1.98 MiB Views 41 views

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