Re: My IBM PS/2 model 35SX build

Posted on 2023-04-08, 11:24

by

by Blavius

in Marvin \ System Specs

in Marvin \ System Specs

Thanks for the write-up, that was fun to read! Beautiful machine. I have a 76i that has the same case, but is a MCA machine with a 486DX. What do you plan to run on it? And do you have a socket for a cpu ugrade? There is a wealth of upgrade possibilities to turn your 386 in a half decent 486 😀

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Re: S3 805 VLB graphics - onboard vs card

Posted on 2023-01-09, 21:33

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Fine, then. Yes, AM5x86 would be better, but I guess you don't have 3volts support. And still if you have an 3 volts adapter it is unlikely that the board will work correctly with it. So I would stick to 66MHz, that is the easist option. No, I don't unfortunately. On my 76i there is a header to …

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Re: S3 805 VLB graphics - onboard vs card

Posted on 2023-01-08, 12:26

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You're thinking in 2023. Think in 1995 instead. A year ago you bought a very expensive 486DX2-66 system with VLB. You don't intend to buy a new PC for another 3 or 4 years (Dutch PC Prive fiscal incentives at the time only allowed one once every 5 years). But this new Windows 95 runs like crap on …

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Re: S3 805 VLB graphics - onboard vs card

Posted on 2023-01-08, 10:11

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for taking the time to look into this, that's very helpful. It's clear that there is not much to gain with buying the 805 card, so I can put that to rest. Very interesting part about DOS performance! I'm indeed building this system to play DOS games. From what I see, games requiring windows …

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S3 805 VLB graphics - onboard vs card

Posted on 2023-01-07, 22:17

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I recently got a new desktop to play around with, an IBM PS/Valuepoint 425SX/S. On paper this 25MHz 486SX isn't very interesting, but it has an 'overdrive' socket and a socketed crystal, which IBM itself says you can replace with a 33MHz one if you need, and I've seen posts of people running it …

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Re: USB to PS/2 keyboard adapter

Posted on 2022-12-30, 20:19

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

rasz_pl wrote on 2022-12-30, 14:44: afaik USB keyboard support was non existent up to ~1998? Bios needs 'USB Legacy support'. $5 solution https://github.com/No0ne/ps2pico Holy moly! I've been looking for something like this for ages. Did you build one?

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Re: What era of computers do you draw the line at collecting and/or using?

Posted on 2022-12-29, 23:04

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sorry to get a little philosophical, this thread made me ponder. Reading though it, a common motive seems to be recreating an experience from back in the day, both in hardware and software - mostly games. As it seems though, because when I thought about it, for me personally it is more nuanced. The …

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

Posted on 2022-12-10, 19:44

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Maybe U1 and U2 will fit there as well. Only 1 person will ever use those. Well, that person and everyone else that will put this in an IBM ;-) I didn't check the thread for a few weeks, and I'm thrilled to see the progress you guys are making. Great job on bringing the noise down and getting …

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Re: IBM PS/2 55SX recapped diskette drive still not booting to Reference disk

Posted on 2022-12-07, 16:56

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I had the same issue with a drive of an IBM L40SX. After recapping the main board the issue still persisted. It turned out there were some traces around the old caps near the motor that were corroded. Managed to sort that out with a multimeter and a botch wire. After that it happily spun away. As …

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Re: Advice needed : systems for a 90's themed company event.

Posted on 2022-12-07, 13:07

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I really enjoy playing red alert over a serial cable with my son. That's on a Pentium 133, on which it runs fast enough. Does take you a good hour or so if you want to comp stomp, so maybe Doornkaat is right and its better to stick to games you can enjoy for a few minuted. Doom deathmatch might be …

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Re: Do dual pentium 4 motherboards exist?

Posted on 2022-12-05, 18:19

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for the detailed writeup dion, very interesting to read. I wonder if you could maybe take a 603/604 cpu and put a bga 478 socket on it? Then put whatever pentium 4 you had laying around on it? Heheh :-) I guess you could, if the socket doesn't check for the missing pins. However, unless all …

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Re: Do dual pentium 4 motherboards exist?

Posted on 2022-12-03, 14:30

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have a Pentium 4 rig running a SL8PZ and a dual Xeon rig with a couple of SL8P3's. What's interesting about this is that both chips have the same CPUID/stepping (0F4Ah/R0). So it's basically the same CPU in both cases but just in a different packaging (LGA775 vs. S604) That's very interesting, …

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Do dual pentium 4 motherboards exist?

Posted on 2022-12-03, 10:04

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have an IBM server from 2003 sitting in the garage with a Xeon Prestonia in it. Looking for a next project, I decided to resurrect this old beast. The motherboard has two sockets, but only one is filled, so I hunted down a VRM and identical Xeon on ebay. For peanuts really, the CPU was just $9. …

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Re: 486 MB frequency

Posted on 2022-11-17, 15:37

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The standard 486 and 486DX pin doesn't have a CLK2 pin (which is named that way, because it receives two times the clock speed). A CLK2 pin is present on 286, 386 and some special early low-power 486 chips. The ordinary 486 processor has a CLK pin instead and expects the actual processor clock at …

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Re: 486 MB frequency

Posted on 2022-11-17, 07:57

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The frontside bus frequency of 33 MHz povided by the mainboard is doubled inside the CPU. So it effectively runs at 66 MHz. DX2 stands for "x2". After a lot of fiddling I found that it is a bit different. In your case the socket receives the 50MHz from the crystal, this goes to CLK2. In a normal ' …

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Re: Should I get a Pentium 1 laptop?

Posted on 2022-11-14, 12:26

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've got a Thinkpad 760 with a TFT screen (single slider on screen!), P1-133, 48Mb ram. I love it! But of course my reasons are particular to my situation: -As I don't have a permanent spot for my retro stuff, its a lot less hassle to take out a laptop than to set up a desktop. -Dos,Windows 95 and …

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

Posted on 2022-11-12, 19:36

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Not sure if you were aware I had a write-up on the cyrix.exe settings. https://www.vogons.org/viewtopic.php?t=45756 You generally want to start with disabling caching of the ROM region, 640k - 1024K, so -xA000,128 -xC000,256 which I think is the same as using -r Hey thanks, I didn't yet see that no …

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

Posted on 2022-11-12, 12:05

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I mentioned earlier that I was having stability issues with my side-by-side interposer in an IBM P70. Vanilla doom ran fine, but basically everything else crashed. I tried fdoom yesterday, which surprisingly froze immediately after startup, not even displaying anything. After some trial and error I …

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

Posted on 2022-10-26, 04:40

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Absolutely; U1 = M74VHC1GT14DTT1G -VCx U2 = M74VHC1GT32DTT1G-VNx I ordered both from AliExpress.

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

Posted on 2022-10-25, 18:48

by

by Blavius

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

v3.14159 CPUInterposer386-486 beta 3.14159.zip How does this look? There is a courtyard violation between cout and r2, but it is fine. we can ignore. :-) the 3d model shows 6 pins but there are only 5 holes don't worry. Sorry, took me a while to find the time to look into this with KiCad. Addition …

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