Re: Bought these (retro) hardware today

Posted on 2019-11-11, 21:19

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You need to add a 16MHz crystal to the card and the missing voltage regulator (either 79L05 or 78L05) and it should start working again. The other missing parts are some capacitors in power stuff that will not be critical but should be there (16V 10µF+).

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Re: PCI sound cards and Chipsets from various manufacturers...

Posted on 2019-11-11, 18:32

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

One will still spend time in writing chipset and/or motherboard specific utilities, though they'll not be overly complicated. UTsource lists the Fintek bridge, though no price for it. I suppose they said it was not available ? I see several on Aliexpress too and not really for a bad price.

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Re: Nexgen - the 486 killer - WIP

Posted on 2019-11-11, 17:14

by

by Tiido

in Marvin \ System Specs

in Marvin \ System Specs

I run a Mach32 and that same Promise IO card at 50MHz VLB with no wait states on OPTi 82C895 based motherboard, it runs pretty nicely but I need 10ns cache to maximise the performance on CPU end.

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Re: PCI sound cards and Chipsets from various manufacturers...

Posted on 2019-11-11, 15:58

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

I have not tried to buy the chip. Next time I am gonna mess with this stuff is when I hook up a CPLD or FPGA to LPC and PCI bus and create the ultimate ISA bridge. But for now my hands are full with some other things...

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Re: hidden refresh and slow refresh

Posted on 2019-11-09, 20:43

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hidden refresh is a method to do a refresh cycle as part of normal access cycle to a DRAM chip rather than needing a dedicated refresh cycle which will be slower, it helps to increase memory bandwidth. All 72pin SIMMs support hidden refresh and most 30pin SIMMs should too, at least 1MB and bigger …

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Re: Need assistance getting a serial mouse working with windows 9x

Posted on 2019-11-07, 12:19

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Whoops, I somehow missed the working in DOS part. I'm not sure what is going on that windows won't work, since two different ones behave same.

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Re: Need assistance getting a serial mouse working with windows 9x

Posted on 2019-11-07, 06:45

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The most probable reason is seen here : Re: M-Tech R418 Motherboard COM Ports unresponsive

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Re: Southbridge Registers?

Posted on 2019-11-05, 04:14

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have written little utilities in QB45 that poke various registers to enhanced state on other chipsets. it is pretty easy if there are no special procedures involved prior/after changing the register(s). in most cases you have an index port to choose what register to read/write and a data port for …

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Re: AW744L II - YMF744 - AOpen Cobra Sound Card - Install SB-Link Header

Posted on 2019-11-04, 03:33

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

It is an analog sound connection to some addon or a modem or something such.

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Re: FOREX 386 Cache board doesn't post

Posted on 2019-11-03, 10:13

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I got a Forex board with FRX36C300 and FRX46C402 and did a chip transplant of the 402, and the board I have now finally functions with cache again while the other board with my old 402 chip stopped working altogether. So it does seem chipset failure is not out of question with these boards... The …

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Re: Is the risk from static damage overblown?

Posted on 2019-11-02, 16:38

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have killed a Play Station 2 with static one time and one other device I no longer remember, and a logic chip by purposefully zapping one pin of it with a spark thingy from a fire lighter. The pin I zapped stopped working, rest of the chip continued to work lol. Vast majority of the devices have …

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Re: Tandy 3 Voice Sound - SN76489 ISA Soundcard Project

Posted on 2019-11-02, 16:35

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

Like this : Filename capacitors.png File size 8.01 KiB Views 1186 views

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Re: Fast Ethernet on ISA

Posted on 2019-11-02, 06:31

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I run an 3C509B at 13.3MHz and no wait states very happily in one of my 486 machine, and on another 386 machine a slightly newer version that has Parallel Tasking written on the chip at 16MHz.

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Re: Tandy 3 Voice Sound - SN76489 ISA Soundcard Project

Posted on 2019-11-02, 03:10

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

47µF will help but not as much as 68pF will. 100pF will work but probably begins to muffle sound. Two 47 is series and then parallel over 3rd 47pF should get something around 70pF which will be fine.

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Re: identify 486 motherboard

Posted on 2019-11-01, 11:04

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

WinBIOS yes. Using an Award BIOS from another board freezes when OS load needs to start and my own attempts at enabling L2 also result in a freeze. This is not a software issue but most certainly an hardware issue and I'm 100% certain a modification is necessary to get cache working right even when …

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Re: identify 486 motherboard

Posted on 2019-11-01, 07:35

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So I spent a while tracing out how the cache connects and it doesn't seem anything is actually wrong as far as connectivity goes and connections from CPU to chipset to cache seem to make sense mostly. All the boards with this chipset require size jumpers and that's where I am stumped, I don't know …

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Re: CM-64 / Cable-Pinout

Posted on 2019-11-01, 05:45

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

With direct connection there may not be enough current to drive the LED in the optoisolator on the receiving end, depending on what sort of resistor is used in series with the MIDI line.

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Re: identify 486 motherboard

Posted on 2019-11-01, 00:48

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The cache ones are all traced out too and there's essentially 3 links to connect upper address lines of the 2 banks together or directly to some pins on the chipset. I don't yet know the significance of it, but the wrong BIOS definitely recognizes that there's 256KB of cache but will crash. I'll be …

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Re: identify 486 motherboard

Posted on 2019-10-31, 13:28

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Someone else can do the diagrams etc. I have now figured out the CPU and cache jumpers, or rather what they are. How exactly they need to be set I don't quite yet know, and the BIOS is not cooperating as far as cache goes. I have tried another ALI BIOS and it works as long as cache chips are removed …

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Re: What retro activity did you get up to today?

Posted on 2019-10-31, 05:06

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I spent a while figuring out the jumpers of my new ALI PCI486 board, the CPU jumpers are now all traced out and most of the functions are now known of them. Now to figure out exactly what they must be set for various CPUs. Cyrix support seems to be the main thing, they have several pins on them that …

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