Re: "upgrading" an old ATX power supply

Posted on Today, 13:51

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ok, I looked at the existing PSU and these are the specs: SCR-20250616-mdxj.png The PSU I would like to use is this one: SCR-20250616-mehe.png The original PSU seems to be a "Pentium 4" type of PSUs, where more Amps are reserved for the 5V and 3.3V lines. But this is an Asus P5S800-VM, socket 775. …

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Re: Requesting info and assistance on this VLB motherboard

Posted on Yesterday, 06:31

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, I agree that the Speedsys results seem to indicate that cache is disabled, however the other results, while not great, are fast enough to cast doubt on that conclusion.. I am not using himem.sys. The Gate A20 only has two options which is Normal and Fast. I have it set on Fast. I'm using …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-14, 08:48

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I had some time to play around with the machine yesterday and it seems that my enthusiasm may have been a bit premature. In 4x clock mode, the performance is strange or inconsistent. (Speedsys in particular) With cache in WT mode, the system scores the following: 4x Clock Mode (133MHz): Speedsys - …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-12, 16:52

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by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi byte_76, Great to hear the patched BIOS works as planned! :) However, getting the L1 cache in WB mode is another matter. The Am5x86 article on my website, that you found earlier, also contains information on how to find the jumper that is connected to the CPU’s WB/WT# pin B-13. A first step is …

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Re: Shuttle AV-18E V1.3 PIII 866/133 no POST

Posted on 2025-06-12, 07:42

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What is the rating of your memory? The Celeron CPU’s work at 66MHz or 100MHz FSB while the PIII’s (866) use a 133MHz FSB. If you’re using PC66 memory, it might not work with the PIII 866 because the board may try to run the memory at 133MHz. You might not even get POST with PC100 memory depending on …

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Re: What can I do to optimize this SS7 board?

Posted on 2025-06-10, 18:39

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

no IRQ 3-6 means, no serial ports (3&4), and no floppy drive (6) I think I can live with that for the time being. At this stage, I don't have the right tools and I'm not confident enough in my skills to fix the missing pins. It certainly isn't easy because the size of the pins are tiny and my …

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Re: What can I do to optimize this SS7 board?

Posted on 2025-06-10, 12:38

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The board is working so I consider it saved already, as I’ve painstakingly repaired the two traces for the pins of the south bridge that are required for the IDE ports to work and I haven’t yet identified any further loss of functionality resulting from the missing pins. The board seems to work fine …

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What can I do to optimize this SS7 board?

Posted on 2025-06-10, 10:53

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I’ve just come into possession of a Shuttle HOT-591P revision 2.0 board. The south bridge has some damage with pins 72 - 75 completely missing. (IRQ3 - IRQ6) Initially the IDE ports were not working and I had to repair traces for pins 69 and 70 which restored functionality to the IDE ports. I’m not …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-10, 08:13

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Believe these boards were commonly used in Brother / Kyodai BCR series PCs in the early-mid 90's which might be another route to a manual...I have an older version of the B870-II with an April 93 BIOS which came as part of such a system, but that board only supports uo to P24T class processors (no …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-09, 16:57

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi byte_76, Great to hear the patched BIOS works as planned! :) However, getting the L1 cache in WB mode is another matter. The Am5x86 article on my website, that you found earlier, also contains information on how to find the jumper that is connected to the CPU’s WB/WT# pin B-13. A first step is …

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Re: IDE drives not being seen

Posted on 2025-06-09, 09:53

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Have you examined the board with a magnifying glass or under a microscope to check for broken traces? I believe the south bridge is responsible for managing the I/O between the IDE ports and the CPU. Also, have you cleaned the board thoroughly?

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-07, 20:44

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi byte_76, Okay, the ATC-1762 BIOS works on your B870-I2 board, great! When you run the Am5x86-133 at 25 or 33MHz FSB, you are not overclocking the CPU when setting the multiplier to x4. I agree that it is the lack of Am5x86 support in the BIOS that prevents POST under these conditions. I’ve …

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Re: Is there a way to add support for this CPU?

Posted on 2025-06-07, 05:46

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Unfortunately the board has an AMI BIOS. I see the Vogons wiki indicates that there is a very similarly named board which does support the VIA CPU's. GA-6VMM PLE133 + 686A https://www.vogonswiki.com/index.php/VIA_C3_Verified_Motherboard_List My board has a VIA 686B south bridge. Here's the Gigabyte …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-06, 18:49

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have identified CLKMUL pin( R-17), it is indeed the 2x jumper position as printed on the silkscreen but the neighbouring pin is connected to ground through a 1 kΩ SMD resistor, not directly to ground. Could that be the reason why the system does boot when the jumper is installed in the 2x …

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Is there a way to add support for this CPU?

Posted on 2025-06-06, 18:34

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have a Gigabyte GA-6VMML Rev 1.0 and a VIA C3 1.2GHz that I'd like to use in the board. The board does not post with the CPU installed. Is there a way to add support for this CPU?

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Re: PSU Fortron/FSP ATX-350PNF with problematic +5 & +12V voltages [Factory layed problem confirmed, WORKAROUNDS FOUND]

Posted on 2025-06-05, 20:10

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I bought a Sparkle Power ATX-250GT yesterday. Replaced 3 leaky caps (2x 1000uf 10V which I replaced with 1500uf because I didn't have 1000uf available and 1x 3300uf 10V). I've tested with no load and I get: -12V: 11.5 +12V: 11.5 +5V: 5.3 +3.3V: 3.4 5V SB: 5.2 With a Hard disk attached, I get: -12V: …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-05, 19:55

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have identified CLKMUL pin( R-17), it is indeed the 2x jumper position as printed on the silkscreen but the neighbouring pin is connected to ground through a 1 kΩ SMD resistor, not directly to ground. Could that be the reason why the system does boot when the jumper is installed in the 2x position …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-05, 08:37

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I see that Jan has explained very nicely how to get the Am5x86 into 4x clock mode. http://www.steunebrink.info/amd5x86.htm I’ll try this out on my board when I have some time to mess with it again. Most likely the CLKMUL pin will be connected to the pin for 2x mode on my board. If that is the case, …

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Re: K6-2/3+ Success on Asus P5A 1.06 - simple mod

Posted on 2025-06-04, 05:35

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Is it safe to install other processors into the P5A ver. 1.05 after doing the resistor mod? I forgot that I had the mod and tested a Cyrix 5x86MX PR200 in there. (75MHz x 2) The processor seems to be faulty as the board doesn’t POST but I’m not sure if I killed the CPU by installing it into this …

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Re: Requesting info and assistance on this VLB motherboard

Posted on 2025-06-04, 05:26

by

by byte_76

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm still struggling to get WB L1 cache working (it is enabled in the BIOS) With Award BIOSes, this often only applies to Cyrix processors (both 486 and 5x86). Those processors have the L1 mode software controllable. On the other hand, late AMD and Intel 486 processors with write-back L1 support ( …

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