Re: Dual Pentium Pro Build Thread

Posted on 2025-01-01, 22:28

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Why is that not mentioned anywhere?! It is considered standard EE knowledge taught at uni. You can find formula for calculating crosstalk in 'High Speed Digital Design: A Handbook of Black Magic' by Dr. Howard Johnson on page 190 192 Great podcast with the guy https://theamphour.com/the-amp-hour-77 …

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Re: Upgrading to a 486 (or 386) on an IBM 5162 using an upgrade card.

Posted on 2024-12-31, 08:28

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

https://forum.vcfed.org/index.php?threads/run … oard-386.47554/ https://xcancel.com/foone/status/1424418405579325442 " IBM 5150 + Intel InBoard to upgrade to a 386, then a voltage adapter to let it run a 486, then using a Cyrix 586 upgrade in place of the 486"

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Re: Problem with sticking keys in DOS games with Socket 370 system

Posted on 2024-12-25, 15:22

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

try to disable DOS HMA (high memory area) DEVICE=[drive:][path]HIMEM.SYS [/A20CONTROL:ON|OFF] [/CPUCLOCK:ON|OFF] [/EISA] [/HMAMIN=m] [/INT15=xxxx] [/NUMHANDLES=n] [/MACHINE:xxxx] [/SHADOWRAM:ON|OFF] [/TESTMEM:ON|OFF] [/VERBOSE] /HMAMIN=m Specifies how many kilobytes of memory an application must …

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Re: Pcchips 386/25

Posted on 2024-12-25, 06:25

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

sys a: c: fdisk make partition active

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Re: Mitsumi 6x CDROM acting weird depending on OS

Posted on 2024-12-25, 06:21

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Linoleum wrote on 2024-12-24, 19:40: I can't believe that just a slight difference is size totally breaks ATAPI/IDE of the slave drive. Its not just difference in total size, size difference suggests different guts = different firmware and defaults. CFs werent really tested for Master/Slave …

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Re: 193 copies of VGA card in Device Manager

Posted on 2024-12-25, 04:35

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

P&P can assign interrupts, but here you only control interrupts and not P&P. Even bios 1.41 is pre win95 release, but maybe fixes enough. At least it includes "Award Plug and Play BIOS Extension v1.0A" Bios does look flashable, you would flash it with something like awdflash.exe, but its best to …

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Re: Upgrading a 386SX - some advice!

Posted on 2024-12-24, 06:37

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Marco wrote on 2024-12-23, 07:24: Dear member, Can I conclude here that I can use a 486SXLC2-G50-PQ to solder on my 386sx mainboard which has the qfp 386sxl 25 AMD on it (without any voltage mods)? looks like G50 requires 3.3V supply?

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Re: FIC PA-2013 hangs on POST, before device listing

Posted on 2024-12-24, 06:30

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by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So slight update, now I somewhat got it to run. It now hangs in the way described in the OP only if I have external cache enabled. Not sure where to look at this point given I redid the joints on all 4 cache chips, and even replaced the TAG RAM chip yet no change in that regard. There was a post …

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Re: 193 copies of VGA card in Device Manager

Posted on 2024-12-24, 06:22

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thats just IRQ assignments. P&P is about much more resource allocation stuff. That manual page is weird. PCI IRQs are Level triggered, Edge would break functionality ? 😮 What is the exact model of your mobo? have you upgraded to latest bios?

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Re: Serial mouse woes

Posted on 2024-12-24, 06:11

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

UMC chip has blown voltage level translators. >6 (DSR): 2.44 VDC You could maybe bodge it to work by adding external MAX3232 and 3V voltage regulator. MAX3232 powered by 3V will recognize logic high from 2V up. That would fix output, but we dont know if receive is working, to test it you would need …

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Re: What retro activity did you get up to today?

Posted on 2024-12-24, 05:50

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Major Jackyl wrote on 2024-12-22, 18:39: Filename 20241222_123128.jpg File size 1.81 MiB Views 774 views File comment Right side of table File license Fair use/fair dealing exception Filename 20241222_123111.jpg File size 1.71 MiB Views 774 views File comment Left side of table File license Fair …

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Re: Pre-VESA Proprietary 32-bit Local Buses?

Posted on 2024-12-24, 05:45

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So far Joindata Local Bus is the weirdest one as it seem to require special proprietary chips on extension cards. mpe's ET4000 https://www.vogons.org/viewtopic.php?p=839838#p839838 uses Appian Peripheral IF P928 https://www.techmonitor.ai/technology/appian_ships_the_p928_fast_local_bus_chip " …

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Re: Register settings for various CPUs

Posted on 2024-12-23, 16:59

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

When using the AHA-1522B (no MEMW# connection), I can execute several DOS programmes from floppy in succession without issue (tried up to 4). DMA_TST provided by Cyrix always passes. It uses the floppy drive as the DMA check. What mechanism is invalidating the L1 cache when the FLUSH# pin on MB is …

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Re: 193 copies of VGA card in Device Manager

Posted on 2024-12-23, 16:50

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Nope, just turn off anything sounding like its about ACPI/P&P and redetect hardware in windows.

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Re: Suddenly 33 MHz not bootable with 386sx anymore

Posted on 2024-12-23, 13:48

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Blue caps look like Tantalums, those either work fine or due to age and moisture ingress go short and blow up 😀 no middle ground.

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Re: Repairing a Promise Eide 4030 plus

Posted on 2024-12-23, 13:27

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Location. C67 68 go under crystal so those are tiny external load caps. C29 C65 are soldered to the big copper plane , most likely ground = decoupling for something. I would guess that on your controller caps are called: TC = tantalum, maybe ~10uf? BC = bulk capacity, maybe 1uf? or anything above …

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Re: Repairing a Promise Eide 4030 plus

Posted on 2024-12-23, 11:00

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

nope, those are in pico range for crystal, TOYOCOM is a generator. C29 from that modem looks like 100nF and should be fine.

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Re: Let's improve video output quality of VGA ISA/VLB cards (First success !)

Posted on 2024-12-23, 10:39

by

by rasz_pl

in Marvin \ Video

in Marvin \ Video

https://www.vogons.org/viewtopic.php?p=1315132#p1315132 In order to get to the bottom of this we need to see few measurements on a scope screen: - Cirrus Logic chip between ground pin 80 and VCC on pins 1, 26, 58, 81, 107, 121, 140 and DAC VCC 72, 85 - Analog R G B capture with fully white screen …

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Re: Suddenly 33 MHz not bootable with 386sx anymore

Posted on 2024-12-23, 10:21

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Indeed it will be much easier to solder big electrolytic caps to already present caps next to ISA slots (blue ones). The only voltage rail you should bother with is +5V connected to Pin B3, B29 and D16. Since you mention it doesnt start with no cards at all I would try adding caps closest to chipset …

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Re: Register settings for various CPUs

Posted on 2024-12-23, 09:55

by

by rasz_pl

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Last I checked, read/write floppy access works fine on AHA-1522B on this GEM motherboard without BARB. without MEMW linking? We are only interested in Floppy reading. Even something as simple as executing two different files from FDD in succession has potential of crashing if DOS loads them up in …

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