Re: Have we found the ULSI MathCo diagnostic utilities yet?

Posted on 2023-09-19, 20:27

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Been trying to archive everything I have, this seems like the best starting point. The disk image was also made on the same system as the mathco is installed and has been since the early 90s. I can also make a flux image of the disk too, just haven't set that all up yet. https://archive.org/details …

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Have we found the ULSI MathCo diagnostic utilities yet?

Posted on 2023-09-06, 19:41

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Retail ULSI Math Coprocessors came with a utility diskette. The last I had seen a few years ago nobody had archived one of them yet. Does anyone have a source for one? I know a few other ones like IIT have finally been found. Thanks!

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Re: XTIDE Can't Boot Floppy

Posted on 2023-09-06, 00:42

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

As a workaround, you could try to not enable 486DLC cache in BIOS and instead use a DOS utility. It's no real solution to the issue, of course, but the right DOS utility may support the same method of cache control as BIOS. If the chipset/socket has the appropriate control lines, I mean. The …

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Re: XTIDE Can't Boot Floppy

Posted on 2023-09-05, 21:13

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

UPDATE: It boots if I disable the internal 486DLC cache. 🤦‍♂️ I guess I need to report a bug?

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XTIDE Can't Boot Floppy

Posted on 2023-09-05, 20:06

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have a ROM card in my 486DLC PC with XTIDE on it. I have a working bootable floppy in Drive A. The system boots to that floppy if XTIDE is not enabled. If I enable XTIDE and try to get it to boot from the floppy it tries to read the disk (drive motor/heads engage) but it says Non-System Disk. Has …

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Re: What happens to the socketed 386DX?

Posted on 2023-08-20, 05:51

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Good looking 386 board. If it were mine would not mess with it if it runs perfect the way it is.. specially if it came with soldered jumpers (there is a reason ;p) Trust me, I know. The draw of this mod is that it's a single pin, and it's reversible. If it involved anything more complicated then I …

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Re: What happens to the socketed 386DX?

Posted on 2023-08-20, 01:39

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sockets on most of those price optimized micro-AT 386 boards are not for upgrading or any user use. They were manufacturing universal boards to be able to use cheapest CPU possible every day/week. CPU (and cache) were the last components mounted on the board before shipping them out. cant use the …

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Re: What happens to the socketed 386DX?

Posted on 2023-08-19, 22:11

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

PAGING RayeR! (I tagged you in the quote) Vogons is such a great resource. I was poking around and found that RayeR has a similar board and modded his with a socket. BTW I did the socket mod on this MB as mine has soldered Am386DX and I wanted also use PGA CPUs like my Tx486DLC that is supported in …

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Re: What happens to the socketed 386DX?

Posted on 2023-08-19, 21:46

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

http://www.amoretro.de/2013/01/kmc-a419-8-acer-ali-m1419-386-cache-motherboard.html This looks quite a lot like your board... Nailed it! It looks like my board is a bit newer than the one in the pics. The date codes on chips point to manufacture sometime after week 41 1992, and my board (solder …

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Re: What happens to the socketed 386DX?

Posted on 2023-08-19, 21:10

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Oh, the manual clearly states about JP8 at least "factory setting do not alter". Haha, yes. I've looked over the board well and found all the JP headers. None of them are good candidates for me to touch. Interestingly neither of the candidate boards have jumpers for CPU selection, so I assume it …

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Re: What happens to the socketed 386DX?

Posted on 2023-08-19, 20:13

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

First of all clean the corrosion with white vinegar :) Yes. I took that picture between cutting off the battery and cleaning the corrosion. It's now nice and clean and looks like all the traces are intact. :) Second, read the manual and remember you have to change the crystal to 66.0MHz for your …

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What happens to the socketed 386DX?

Posted on 2023-08-19, 19:14

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

On this motherboard (pic attached) there is both a soldered 386DX and an open socket. What happens if I drop a CPU in the socket? Does it override the soldered one? I don't see a jumper that disables the CPU and I don't want to mess something up by populating the socket. Also, it looks like this …

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Re: Incessant Beeping

Posted on 2023-07-31, 02:41

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

mkarcher wrote on 2023-07-30, 17:38: I suggest you to try a replacement for the keyboard IRQ1 handler: Try loading KEYB in DOS. AFAIK, even if you use KEYB US, you replace the BIOS IRQ1 handler by the IRQ1 handler integrated in KEYB.COM. You are my hero! That actually worked. Thank you!

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Re: Incessant Beeping

Posted on 2023-07-30, 18:02

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The A20 toggling option is not supposed to send any data from the keyboard controller to the host, it should just send data from the host to the keyboard controller. There should be no IRQ1 (keyboard IRQ) triggered when using the keyboard controller to toggle the A20 line. I see a BIOS chip with a …

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Re: Incessant Beeping

Posted on 2023-07-30, 17:16

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd guess it's the keyboard controller (8042 chip) malfunctioning. A hi-res photo of the board would be helpful. A hi-res photo of the board is attached. I replaced with 8042 chip with a known good one and the behavior is the same. BTW, the battery hasn't leaked at all. There is zero corrosion, all …

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Re: Where the heck do I get capacitors?

Posted on 2023-07-28, 17:41

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What exactly constitutes a fake capacitor? How do I know if I've bought one? It varies widely. The best case with a fake is that it came from the official factory but failed QA testing because it was out of spec and sold off at a steep discount. In that case you might never notice. you likely wont …

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Re: Where the heck do I get capacitors?

Posted on 2023-07-28, 14:57

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There are a stunning number of fake caps up for sale. Buying from Mouser and Digikey ensures that you will get authentic ones. Never buy from Amazon, and only buy from eBay if you have a trusted and reliable source. As for selection, the capacitance is most important but you have flexibility with …

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Re: Incessant Beeping

Posted on 2023-07-28, 02:26

by

by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd guess it's the keyboard controller (8042 chip) malfunctioning. A hi-res photo of the board would be helpful. Yeah, I wondered about that. I will work on getting a photo of the board. I'd need to break the system down to do that so it will take some time. The chip is a MEGAKEY™ (1994, AM) marked …

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Incessant Beeping

Posted on 2023-07-27, 21:13

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'll go ahead and get the basics out of the way: - I've run Memtest86+, the RAM is fine - I've tried both with and without external cache, no difference - I've even tried different graphics cards and even different CPUs, no difference I have a C&T Peak DM 386DX I am trying to tame. In DOS while …

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Re: Drive Issues with a C&T BIOS

Posted on 2023-07-24, 05:35

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by LChackr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

For future readers, the XT-IDE BIOS solved the problem. The board boots from flash without any trouble now. 😀

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