Re: Where to start diagnosing a dead 3dfx monster

Posted on 2021-07-21, 16:47

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hey, at least the Monster is drawing stuff again! That's great news, it means that the output stuff and business end of the GPUs is probably working at least. Did you check to make sure you didn't accidentally bridge any of those tiny pins together on the chip you replaced? Also look for traces that …

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Re: Upgrade paths for the 386 - Yield?

Posted on 2021-07-15, 18:44

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Maybe some TTLs that interface the chipset to the cache are marginal/bad? I'd like to think it wasn't a problem with the cache controller.

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Re: Chips & Technologies F64300 VLB vga question

Posted on 2021-07-12, 06:11

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My F64300 works fine on my U5S-33MHz in zero waitstate. Guess it depends on the motherboard and card quality or something.

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Re: 286 mobo cpu upgrades (386sx+) , opinions?

Posted on 2021-07-11, 20:35

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd say a 20MHz 386SX would better match a 12-16MHz 286 when running generic 8088/8086 code, everything else (chipset, wait states, etc.) being equal. 10MHz is a little too conservative. Now, if said 386SX was doing nothing but executing 386 code that requires a lot of 32-bit transfers, then yes, I …

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Re: AMI Color BIOS (1993 and earlier) modification in hex editor

Posted on 2021-07-08, 02:35

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank you very much for posting this!

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Re: How about a MR-BIOS ROM file repository?

Posted on 2021-06-30, 18:31

by

by Eep386

in Marvin \ Software

in Marvin \ Software

Just a quick report - the MR BIOS image for the Octek Jaguar V seems to work on my C386MX board with an MX305/306 chipset. And it works vastly better than the AMI BIOS it replaced. Using the stock 386DX-40 CPU, no FPU. Don't have a 486DLC to test.

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Re: Where to start diagnosing a dead 3dfx monster

Posted on 2021-06-20, 01:23

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

CVDD and DVDD are often connected together I think?

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Re: Where to start diagnosing a dead 3dfx monster

Posted on 2021-06-19, 15:28

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Using a multimeter, test pins 12 and 24 of the P15C3384 10-bit 2-port bus switch chip there. If they are shorted, then try removing the chip and re-testing the pads for pins 12 and 24. If they're still shorted, the fault is elsewhere (and you can put the chip back in). On the other hand, if the …

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Re: Help (re)building a 486

Posted on 2021-06-12, 16:09

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The easy way to get the total cache is to watch the boot-up sequence. At some point it should say something like '256K CACHE ENABLED'. If it's an Award BIOS, then the cache will be listed on the final sign-on screen which shows the 'specifications' of the system. For example, for 256K cache, both …

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Re: Yet another 486 DX4-100 build

Posted on 2021-06-07, 15:51

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The noises you're hearing during Himem's memory test with the CT2230 / CT2290 is possibly due to floating op-amps on them picking up noise from the ISA bus. (Creative got really lazy and left several portions of quad amps unconnected.) Changing the surrounding hardware will help very little.

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Re: Help (re)building a 486

Posted on 2021-06-05, 16:26

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah, you can replace their entries in AUTOEXEC.BAT or CONFIG.SYS, just by overwriting or deleting their mentions in those files. If you'd rather temporarily "dummy out" an entry in AUTOEXEC.BAT, put REM in front of the entry: REM C:\whatever\lol.exe Another thing you can try for now, in AUTOEXEC. …

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Re: Help (re)building a 486

Posted on 2021-06-05, 16:04

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What is the report you get when you type MEM at the DOS prompt? You can try replacing certain device drivers with newer and more efficient ones. One obvious candidate is MOUSE.EXE. Hunt down CuteMouse / CTMOUSE and replace MOUSE.EXE with it, it will free up about 4-6K of conventional memory. It will …

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Re: ET4000AX variants

Posted on 2021-06-03, 16:55

by

by Eep386

in Marvin \ Video

in Marvin \ Video

Power draw for one of these cards varies by the number of chips and the chips they use. While I don't have exact figures, I'd imagine that the more modern cards that use 256Kx16 SOJ DRAMs will possibly use a little less power than older cards which use up to 8 or more DIP DRAMs. The RAMDAC used can …

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Re: Help (re)building a 486

Posted on 2021-06-02, 17:26

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well, you could leave the 33Mhz osc in to run your DX-50 at DX-33 speed. This would effectively be underclocking the part. One reason you might do this, is to get the chip to run (quite a bit) cooler, or to see if your game wouldn't be satisfied with a lower speed anyway. The DX2 OTOH will see …

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Re: Help (re)building a 486

Posted on 2021-06-02, 16:27

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It's trading memory speed for processor speed. If the game you're running is CPU intensive, then the extra CPU speed will matter more. On the other hand if it's doing a lot of memory or I/O thrashing, then the faster bus will be more meaningful. It depends on the game you want to run. Empirically …

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Re: Help (re)building a 486

Posted on 2021-06-02, 14:59

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd vote the Trident 8900CL or 8900D (don't bother with the 8900B or 8900C, they're much slower). 16MB of RAM isn't strictly required (unless you plan on playing more complex games) but is quite nice to have, if you can find it cheap then by all means use it. One relatively cheap upgrade you can do …

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Re: Help (re)building a 486

Posted on 2021-05-31, 15:30

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Those are generally good recommendations for a mid-level 486, but I've a few suggestions and comments of my own: In ISA form, the Trident 8900CL or 8900D are very close in speed to an ISA ET4000AX in most cases, but are a lot cheaper on eBay. The 9400CXi and especially 9440(AGi) are even better, but …

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Re: Help (re)building a 486

Posted on 2021-05-29, 03:44

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The DX2 should just use the DX jumpers. The multipliers are internally set on the 486DX2. Did you buy an Intel or AMD DX2? Some boards jumper the chip differently depending on the brand used, but I don't see any Intel or AMD distinctions in the TH '99 jumper listing anyway. It's also possible your …

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Re: Help (re)building a 486

Posted on 2021-05-29, 02:57

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The LED display will not prevent the system from booting. It's a purely cosmetic detail. The jumpers vary from display to display. You'll need to see the display's PCB to know what model to look for. As the majority of documentation for these displays is lost to time, your best bet is to look for …

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Re: Help (re)building a 486

Posted on 2021-05-29, 02:51

by

by Eep386

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Oh. In that case, the LED display on the front of the case is configured using jumpers on the display itself. It will always say 25 MHz unless you change the jumpers.

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