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Re: New 486dlc build problem.

Posted on 2021-06-12, 10:33

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank you Deunan. :-)With your suggested settings the CPUs L1-Cache is enabled in write through mode (that is what the cyrix diagnosis software tells me). Is it possible to set it to WB-mode? Are there any other settings necessary beyond the bios settings? Do I have to use the cyrix.exe as on my …

Re: New 486dlc build problem.

Posted on 2021-06-07, 10:05

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

OK. I modded the board as suggested by Deunan: IMG_20210607_115441.jpg IMG_20210607_115818.jpg I installed a jumper for JP76. I connected the 386DX's pin 54 (FLT) to Pin 4 of the (missing) U99-IC. (The U99 CLK-generator-IC is missing in my board. It uses the CLK-generator in U35 instead.) Pin 4 of …

Re: New 486dlc build problem.

Posted on 2021-06-04, 20:24

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I measuered again and yes, pin 54 (FLT) is not connected to GND directly. I must have accidentally hit the adjacent pin 55. I used a much finer probe this time. So thank you Deunan. You saved my day again. :-) And yes, you are also right, one pin of that (missing) jumper you mentioned (JP76) is …

Re: New 486dlc build problem.

Posted on 2021-06-04, 11:03

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi everyone :-) ! It has been almost 3 years since the last post in this thread. I have a similar problem and therefore I thought I should rather post it here than in a new thread. My mainboard is a "Unichip 367C Rev 1.0" or "UNI-386WB". The following picture is from amoretro.de: unichip_uni-386wb_ …

Re: unknown 80286 motherboard - identification, manual and bios wanted

Posted on 2021-05-25, 10:25

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank you very much evasive 😀. This really helps a lot 😀

unknown 80286 motherboard - identification, manual and bios wanted

Posted on 2021-05-25, 06:24

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I recently purchased this beautiful 80286-motherboard. Unfortunately I couldn't find out much about it yet. It has a SUNTAC ST62C241 chipset. Filename my board.jpg File size 379.7 KiB Views 96 views Can anybody identify this board? Or maybe even provide a manual or a BIOS-file? 😀 Thank you for …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-23, 10:59

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hello megatron-uk, thank you, I will try your suggested cyrix setting next. During the last days I was busy with some tests. It seems that my board has 2 nasty limitations: 1.) The chipset is stable at 33MHz. The chipset doesn't like 40MHz. 2.) Even though the manual suggests that the board can use …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-21, 07:30

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Weird things are happening now. Maybe you were right Deunan and I do have faulty cache memory. Memory test halted during BIOS-POST at 1472kb (It should have gone up to 4M). The POST-screen said "001472 KB OK" and CMOS Memory size mismatch, Press F1.... After saving the BIOS-settings my system booted …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-21, 03:00

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Here is VGABENCH. I am currently using a really slow OAK VGA-Card with 512kb video memory. When replacing the 486DLC with a 386DX-40 my system scores 14.3 in this test: IMG_20210521_040216.jpg I only had Speedsys v4.78 ready for this test, which reports a 13MHz CPU-clock (Was it v6.00 , which works …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-21, 02:40

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

These are my BIOS settings. I am using slow (almost the slowest, DRAM read can be set to 4WS) memory and cache timings for now. I disabled the two non-cachable segments: IMG_20210521_031537.jpg IMG_20210521_031641.jpg I skipped config.sys and autoexec.bat and I ran cyrix -q: (This is what cyrix.exe …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-20, 18:16

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank you Deunan. This is really helpful. I will run cyrix -q and post the results tonight. As for the cache: I am using a total of 32Kx8=256K with a 32K tag ram chip and they all are 15ns chips . The cache chips worked fine in my 486 board.

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-20, 10:59

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So far I couldn't get the CPU working properly with L1 Cache enabled with the BARB method. I think I will open another thread, especially for the 486DLC on my Soyo SY-19G mainboard. I am rather helpless regarding various BIOS settings. With the default BIOS settings my PC wont even boot - it is …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-20, 09:34

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Never heard of that option. I'd still try that (on and off) with BARB and benchmark. It will be obvious if the CPU is flushing cache constantly, the performance will drop like a rock, possibly even below 386DX levels. Obviously the HW mod is better but software is easier and faster to configure and …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-20, 06:12

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I want to run a 486DLC on a Soyo SY-19G 386 motherboard with an ETEQ 82C4901 cache controller. Why not try BARB first? No support for hidden refresh in BIOS? Hello Deunan and thank you for your reply. I checked the bios. The only thing I can do is to enable or disable "concurrent refresh". No …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-19, 16:53

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I want to run a 486DLC on a Soyo SY-19G 386 motherboard with an ETEQ 82C4901 cache controller. Unfortunately I cannot find a data sheet or any other documentation for the 82C4901 chip. I am trying to get the HLDA-Signal from the cache controller in order to feed it into the FLUSH-circuit for my …

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-19, 14:37

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Oh. I found it here: Toshiba T5200 mods and upgrades 😀... "The A20 mod is a wire from Pin 8 of IC 43 to pin F13 (A20M#) of the 486 CPU (blue wire)". But what does IC43 do? Can someone please explain this to me? Thank you and best regards 😀

Re: Hardware mod for L1 cache support on Cyrix 486DLC/SXL CPUs

Posted on 2021-05-19, 14:17

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well I got the TI486SXL2 working on my T5200 with DMA cache flushing and a20 gate support. Here's a photo of the mods: t5200mod.jpg The blue wire is the A20 gate and the yellow ones plus the IC are the recommended flush circuit from the TI486SXL2 databook (wired for serial cache). I also had to …

Re: BIOS update needed for DTK PKM-0033S or Gemlight GMB-486SPS

Posted on 2020-11-11, 16:07

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank you very much 😀! I couldn't find these BIOSes anywhere.

Re: BIOS update needed for DTK PKM-0033S or Gemlight GMB-486SPS

Posted on 2020-11-10, 23:48

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I checked all the wayback captures for gemlight and it seems v2.05 was the latest BIOS. I wonder if the GMB BIOS is any different from the PKM BIOS. http://web.archive.org/web/19961219082235/http://www.gemlight.com.hk/ GMB-486SPS/PKM-0033S SiS 496/497 486 PCI Motherboard 4WSSG205.BIN for GMB-486SPS …

Re: DTK PKM-0033S motherboard restoration

Posted on 2020-10-08, 12:21

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I figured R71 out myself 😀. R71 is 4.7kOhms. No luck on R89 yet. It seems that R89 is connected to the AT-power good signal, which turns from 0V to +5V as soon as the power is good ... so maybe R89 is just a pullup-resistor?

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