Re: Forex 80386 with AMI-Bios hangs at "A0"

Posted on 2019-12-01, 07:48

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have almost same board and this is interesting, this board isn't supposed to work with 256KB cache and POST never completed (same error) when I installed some. You seem to have 256KB of cache there and with this modification it'll work. Does it show the right amount of cache and is it enabled with …

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Re: MB-4D50L doesn't hold date/time

Posted on 2019-11-30, 19:16

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's the resistor values seen on all the existing boards I have had access to, most have 150ohms, some have 220 and one had 270ohms. They did have NiCd batteries originally though.

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Re: MB-4D50L doesn't hold date/time

Posted on 2019-11-30, 18:42

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

D2, D3 and R22 are gonna be necessary. Diodes should have lowest possible voltage drop and resistor is something between 150...270ohms, setting the charge current for the battery.

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Re: VRAM vs DRAM

Posted on 2019-11-30, 15:17

by

by Tiido

in Marvin \ Video

in Marvin \ Video

Having more bandwidth for the CPU end means it will have to wait less after the graphics core operations which always get priority. Higher performance things have FIFOs and caches to soften the problem.

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Re: VRAM vs DRAM

Posted on 2019-11-30, 14:32

by

by Tiido

in Marvin \ Video

in Marvin \ Video

They should have added decimal notation thing instead. I refuse to use the mibs and kibs, if I want to express the decimal bytes I'll use MeB and KeB etc. instead

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Re: VRAM vs DRAM

Posted on 2019-11-30, 14:22

by

by Tiido

in Marvin \ Video

in Marvin \ Video

I think VRAM has become an umbrella term for a variety of different memory technologies that happen to suit graphics well. The original VRAM was indeed dual ported memory. Second port is serial access and designed for stuff like framebuffer readout for display purposes so that main port can be used …

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Re: UMB drivers for Intel 420EX and ALi M1489 chipsets

Posted on 2019-11-30, 04:45

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ok, DOS 6.22 works perfectly here too but I don't have the latest BIOS but one step before (07), since I was unable to locate the lastest BIOS anywhere. I went from 05 to 07 but 08 eluded me. Perhaps you have the BIOS update package left somewhere ? The board has soldered flash chip and getting it …

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Re: AWE64 Gold Engineering sample

Posted on 2019-11-30, 04:41

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

The 3 letters after CTxxxx number is code for manufacturer of the chip from what I have understood. Creative cannot produce the chips themselves and various companies like OKI, Sharp, UMC, NEC, Toshiba and others are making the physical parts for them. Chip with different manufacturer code functions …

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Re: Need socket 7 Cyrix MediaGX/NS Geode pinout

Posted on 2019-11-29, 14:39

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Grounding the signal will turn the power supply on so on that regard it is functioning like ATX PSUs.

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Re: VRAM vs DRAM

Posted on 2019-11-29, 10:30

by

by Tiido

in Marvin \ Video

in Marvin \ Video

My SGRAM based Rage 3D II card is faster than the DRAM based version, I no longer remember by how much but on a 486DX4 based machine Doom gained several FPS from the SGRAM card. My VRAM based VLB Mach32 is nearly as fast as ET4000W32i in DOS, write speeds are almost same, reads slightly worse and in …

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Re: UMBARIES.SYS, UMB driver for i420EX chipset

Posted on 2019-11-29, 04:40

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have updated the first post with the ALi driver and topic is now no longer specfic to Intel chipset. I will add some more chipsets drivers in coming future ~ Thank you Tiido ! Now I have working UMBs for my every retromachine. You're very welcome ! What is the board and OS you are using ? Does it …

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Re: Has anybody here risked trying to "hardmod" a better SnR ratio?

Posted on 2019-11-28, 08:28

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

Your best bet is to make use of that SPDIF output signal. It is 3.3V and incapable of driving a 75ohm load that normal coax inputs are on whatever you want to connect it to so there's a need for a buffer circuit.

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Re: UMBARIES.SYS, UMB driver for i420EX chipset

Posted on 2019-11-28, 06:16

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My driver can be initialized so it just enables UMBs and I used this to debug stuff, and HIRAM fails still so I'm quite baffled. I am doing 2F stuff too, though a bit differently. HIRAM uninstalls 2F when all UMBs are allocated, I uninstall 2F as soon as XMS function call address is passed over, …

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Re: UMBARIES.SYS, UMB driver for i420EX chipset

Posted on 2019-11-28, 03:31

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm not sure how can I get the footprint to nothing, you cannot load something high before UMBs are made available and the amount of code that does in my case is the 192 bytes. Perhaps if I copy the driver high manually into the UMB area I unlock, and somehow find information about DOS memory …

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Re: NCR System 3434: The Single 486 MCA Monster

Posted on 2019-11-27, 13:12

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

oh wow, what a machine, it looks as tall as my computer desk itself hahaha

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UMB drivers for Intel 420EX and ALi M1489 chipsets

Posted on 2019-11-27, 12:53

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Here's a growing collection of UMB drivers I have been making. Each driver has its own little section and download links of driver and the documentation are in the end of each section. Next in line are OPTi 82C895 chipset, SiS471 and SiS496. UMC chipsets would be good to do aswell and some 386 …

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Re: Has anybody here risked trying to "hardmod" a better SnR ratio?

Posted on 2019-11-27, 03:08

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

Since SPDIF is digital, if I can get a working port hard modded onto this clone card, I wouldn't have to worry about noise ever again right? Assuming I plug the digital source into something that has FAR better analogue outputs than this thing does. If the analog inputs don't go through ADC process …

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Re: Has anybody here risked trying to "hardmod" a better SnR ratio?

Posted on 2019-11-26, 11:26

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

Lack of components can also mean inadequate filtering of input voltage or analogue audio as well. These junk $5 PCI cards often have none of either.. Even the cheapest cards have the necessary linear regulator for analog section. You need to be very incompetent to botch up a single chip design such …

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Re: Fabricating a New Turbo Display

Posted on 2019-11-26, 10:58

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Changing to a different MCU with internal RC clock or something would be better choice if cost is lower, you have less stuff to assemble also. You should fatten up all the power traces, it will reduce any mysterious problems that may happen (the MCU could mibehave due to ground bounce or such), and …

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Re: Has anybody here risked trying to "hardmod" a better SnR ratio?

Posted on 2019-11-26, 10:51

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

The less parts are there, the less other sources for the noise are there. 99% of that noise comes from the sound chip itself, the analog sections in it just are not good. SPDIF comes from a certain pin on the chip, it isn't wired to anything but with a mod you can surely get the signal out and …

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