Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on Today, 05:33

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Aerion wrote on Today, 05:20: maxtherabbit wrote on Yesterday, 16:56: I'll be damned, looks like you got them up line up with an overlap huh. Nice work The pins of the header & socket have to be shortened so that it fits properly on the PCB... Obviously but it's a fit in the XY plane which is …

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Re: 286 dead, long live the 286! Sourcing and building a fast 286 replacement

Posted on Yesterday, 19:50

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looking at the best perf numbers posted on the Estonian forum. That's about 10-20% slower than what i see here at the same 20MHz frequency. Figured i should bring it up. slower than what, the 200 series VLSI? and are their numbers from a true 286 or a 386sx? That was done way back in the olden days …

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Re: 286 dead, long live the 286! Sourcing and building a fast 286 replacement

Posted on Yesterday, 18:17

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

pshipkov wrote on Yesterday, 18:04: Looking at the best perf numbers posted on the Estonian forum. That's about 10-20% slower than what i see here at the same 20MHz frequency. Figured i should bring it up. slower than what, the 200 series VLSI? and are their numbers from a true 286 or a 386sx?

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on Yesterday, 16:56

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'll be damned, looks like you got them up line up with an overlap huh. Nice work

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Re: 286 dead, long live the 286! Sourcing and building a fast 286 replacement

Posted on Yesterday, 15:25

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's the VLSI SCAMP I mentioned earlier. Good luck sourcing one they are rare and $$$

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Re: any tips on desoldering the dallas DS12887A from a AOpen AP53

Posted on Yesterday, 15:22

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by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

If you're serious about retro computing/gaming or electronics you really should invest in a desoldering station for through-hole removal work - it does away completely with the mess of desolder braid. Probably one of the best purchases I've made in years (well, technically it was a christmas gift …

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Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 15:19

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by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

HT12 is a good chipset, so is VLSI Scamp. Try to find a different board that uses one of those

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Re: Evergreen 486 SuperChip - settings for DIP switch?

Posted on 2021-01-17, 03:47

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

As rare as that thing is it might actually be worth several hundred, I don't know that I'd go hacking on it.

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Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-16, 15:55

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by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Next steps on this is to fit a DIP socket for the oscillator so that I can run tests with various speeds (looking in my parts box I have 32, 38, 40 and 50MHz oscillators) and several processor brands and speeds (two AMD-16 with different date codes, a Harris-20 and a Harris-25). I expect, based on …

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Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-16, 03:32

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by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

DRAM ram access times vs wait states required is not a strict function of CPU clock, the chipset's memory controller can be relatively slower or faster necessitating faster memory on a different board at the same CPU clock what clock speed are you running at now? I can't find it mentioned and the …

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Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-15, 14:25

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

12.5MHz for the ISA bus is no big deal. Most cards will handle it just fine. Get that battery off there and send it to hell RFN

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Re: Keyboard unresponsive and lagging on Doom (and Apogee games)

Posted on 2021-01-14, 15:53

by

by maxtherabbit

in DOS

in DOS

You need *both* USBMOUSE and CTMOUSE. USBMOUSE must be loaded first

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Re: CRT Test suit for DOS or Windows?

Posted on 2021-01-13, 04:50

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by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Nothing for pure DOS?

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Re: DOS Memory Management on a 80286 with 2MB RAM

Posted on 2021-01-13, 04:48

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by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ok then I'm sure you know that himem by itself will not provide UMB services in shadow ram. First you need a chipset that can even support it, many early 286 boards do not. Second you need an installable device driver to control it, like UMBDRVR or The Last Byte.

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Re: Let's fix some PS/2 floppy drives!

Posted on 2021-01-13, 00:13

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Are you aware that the edge connector is supposed to have the index signal driven only if the drive is selected? So you need to ground DS1 (Pin 12) on the edge connector, otherwise the drive is passive on the Shugart Bus. If you lost the DS jumper (should be installed in DS1), you obviously can not …

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Re: DOS Memory Management on a 80286 with 2MB RAM

Posted on 2021-01-12, 22:00

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by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

i'll say it again, good old basic himem.sys will give you hma and umb memory for devicehigh/loadhigh. Eh how is that even possible? why would it NOT be possible? a 286 has the full 24 bits of address bus lol EDIT: I now see that he mentioned UMB, which it won't give you my bad. HMA on 286 is good …

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Re: DOS Memory Management on a 80286 with 2MB RAM

Posted on 2021-01-12, 18:55

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

QRAM only works if you either: 1) have LIM 4.0 EMS hardware - either a discreet add-on board or built into the motherboard, or 2) have a supported shadow RAM chipset

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Re: MUS-2020 Prototype - Creative Game Blaster Clone

Posted on 2021-01-12, 03:57

by

by maxtherabbit

in Marvin \ Sound

in Marvin \ Sound

please pull back the solder resist off the card edge

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Re: 286 dead, long live the 286!

Posted on 2021-01-10, 16:16

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

the 1542 with the updated ROM BIOS will support my 75GB external SCSI HDD. DOS can only see the first 8GB of course That's very interesting to know! Have you ever attempted to use Win 98SE / Dos 7 to create or access large FAT32 partitions on it? Negative but AFAIK it should work. Pretty sure the …

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Re: 286 dead, long live the 286!

Posted on 2021-01-10, 15:46

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

the 1542 with the updated ROM BIOS will support my 75GB external SCSI HDD. DOS can only see the first 8GB of course

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