Re: ISA controller cards - Winbond not working

Posted on Yesterday, 20:54

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

All I can say is the Winbond "W83757F/AF" chips die very very often. I just replaced 3 of them on 3 different mainboards. New old stock W83757 are nearly impossible to find today and I think I know why...

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Re: FIC VA-503+ and K6-2+/570

Posted on 2023-05-31, 04:50

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

ziemer wrote on 2023-05-30, 22:29: How did you setup the multiplier of 6.0, the manual lists a max. of 5.5 ? "x2" = "x6"

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Re: Can someone help identify this socket 3 motherboard?

Posted on 2023-05-30, 05:58

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Skyscraper wrote on 2023-05-29, 11:28: I can feel the smell of those "cache chips" all the way from here... no way those are real. ...and JP47 is wired in a way that makes BIOS report "256K cache" at the POST summary screen.

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Re: Help - did I fry my motherboard?

Posted on 2023-05-30, 05:06

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

PSU testers don´t help here, because they just measure the voltages without being a realistic load for the single PSU rails. The tester will pretend the PSU is o.k. even while one or more voltages break down under regular load / operation. These testers can only indicate if a voltage is missing or …

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Re: L5 on Ga-586tx3

Posted on 2023-05-29, 19:30

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

These are for filtering the 5V USB supply voltage (EMV), they must stand the full current caused by the connected USB devices. On early USB mainboards they used through hole "ferrite beads" with very low inductivity, very low DC-resistance (0.05 Ohm) and designed for currents of 1-2A. There are also …

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Re: Reviving PAT48SA mainboard

Posted on 2023-05-29, 16:55

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Never underestimate the soldering side during a troubleshooting! Good work 😀

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Re: How can I safely transplant a 160-pin QFP chip?

Posted on 2023-05-29, 14:12

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Good idea, I´ll think about a new (better) title for this topic and edit it. In the meantime I found that "DMA channel 2" is indeed used for floppy-drives in AT systems, so a dead "DRQ2" input at the 82C362 would explain the failing floppy drive. Maybe someone shorted pin6 (DRQ2) and pin7 (-12V) …

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Re: How can I safely transplant a 160-pin QFP chip?

Posted on 2023-05-29, 12:22

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for the info. Maybe I shouldn´t have reopened this thread from more than a year ago. At the moment it´s all about the question if the odd DRQ2 line behaviour is caused by a defective bus-controller. As for removing chips it depends on the situation. When a known defective chip has to be …

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Re: How can I safely transplant a 160-pin QFP chip?

Posted on 2023-05-29, 10:40

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It seems I have yet another case of a defective Symphony SL82C362. It´s on a FIC "386SX-20/25S": 386sx_20_25S.JPG The mainboard POSTs, video, keyboard etc. are working, RAM (8MB at the moment) and Cache (128K) are detected correctly, but no matter what super-I/O I try it cannot boot from floppy or …

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Re: Reviving PAT48SA mainboard

Posted on 2023-05-29, 07:02

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It´s a pity since the mainboard is in very good condition and the battery has done very little damage. Time to think about some loose solderings at / or even a defective SiS 85C460 chip.

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Re: Completing a FIC 486-GACV

Posted on 2023-05-28, 17:13

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Both DX2 / 66 and AM5x86 / 133 need 33MHz oscillator frequency. Ii is set by jumpers JK1-JK4. If the frequency is unstable (with the 5x86 as well) the oscillator circuit or the crystal could be the culprit. You will also need the jumper array "RC1" that isn´t needed for DX2. Sometimes it´s missing …

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Re: Completing a FIC 486-GACV

Posted on 2023-05-28, 17:03

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The jumpering must be 100% accurate to make sure DX4 or 5x86 CPUs are detected correctly.

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Re: Completing a FIC 486-GACV

Posted on 2023-05-28, 16:54

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It´s all in this thread. You can see all the general jumpering on my "8GACV.jpg" picture above. The complete jumpering for the AM5x86 - 133 CPU can be seen in picture "GACV133.jpg" above. The output voltage of the VRM circuit is determined by the resistors R68 and R69 alone. For R69 = 2K and R68 = …

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Re: Reviving PAT48SA mainboard

Posted on 2023-05-28, 07:42

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

We can´t be sure this is sufficient to turn off the cache chips. To be on the safe side I would remove all cache /TAG chips. Defective cache chips can indeed prevent a system from starting. Have you checked the single thin trsace that seems to end somewhere under the PSU connector for continuity? It …

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Re: Reviving PAT48SA mainboard

Posted on 2023-05-28, 06:34

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

How did you disable cache memory when you cannot enter BIOS?

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Re: Asus P/I-P55T2P4 Rev 3.10 Tag Ram

Posted on 2023-05-28, 05:18

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Here you go Filename ctcm17a.zip File size 97.59 KiB Downloads 4 downloads

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Re: Asus P/I-P55T2P4 Rev 3.10 Tag Ram

Posted on 2023-05-28, 05:09

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The reason why I recommended you use CTCM"7" (seven!) is that it´s results are more straight forward. It explicitly tells you the cacheable areas of L1 and L2.

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Re: Asus P/I-P55T2P4 Rev 3.10 Tag Ram

Posted on 2023-05-27, 05:22

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You do need the 2nd TAG chip in order to enable the full 512MB cacheable area. It´s not about TAG size here but about expanding the TAG I/O bus from 8 to 11 bit. You can check the difference with the tool "CTCM7". If you run CTCM7 on your current configuration you will see that out of 96MB RAM only …

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Re: SBC with too high regulator voltage at 3.5V causing 430HX to run hot.

Posted on 2023-05-22, 05:36

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The intel 430HX chipset operates with 5V supply voltage . Some I/O interfaces operate at 3V, some at 3/5V and some at 5V. The onboard voltage regulator on non-split voltage socket 7 mainboards provides a voltage that depends on the CPU core voltage needs (3.3, 3.45...). A voltage of 3.5V that …

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Re: Shuttle HOT 555 VER 1.41 BIOS

Posted on 2023-05-19, 18:28

by

by majestyk

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

By checking the BIOS chip´s type number. You´ll probably have to remove the sticker.

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