Re: DTK PKM-0033S +5V pin overheating + PS/2 mouse implementation

Posted on 2013-07-13, 04:46

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

SiS 497 pin 8 should be connected to pin 36 of the keyboard controller (MS-OBFO pin). I hope this is the only missing link. On the DTK board, there is no connection here, whereas the 4DPS board has this connection made. I've had to pack my stuff for the weekend, but will re-test this as soon as …

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Re: Smallest 486 MOBO I've seen

Posted on 2013-07-12, 20:00

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

For 100,000 boards, the cost might be more like 1 cent :) I suspect it is because the greater the cache amount the tighter the cache timings become (at least in my experience). They wanted to eliminate the risk of people finding out that more cache = slower timings. This seems very motherboard-, FSB …

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Re: DTK PKM-0033S +5V pin overheating + PS/2 mouse implementation

Posted on 2013-07-12, 19:38

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I beleive the IDE controller is part of the SiS 496/497 chipset duo. I didn't see a 640 chip on the board. The primary IDE port works perfectly fine. The Holtek manual shows different wiring for the keyboard controller for in AT keyboard mode and for keyboard + PS/2 mouse mode. I followed the latter …

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Re: DTK PKM-0033S +5V pin overheating + PS/2 mouse implementation

Posted on 2013-07-12, 10:16

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So far I have been successful in installing Win98SE and NT4.0 using a PCI SCSI controller. On the other hand, when using the Promise Ultra100 TX2 controller with an IDE drive and you go to shutdown Win98SE, the HDD powers down then up again before displaying "it is now safe to turn off your computer …

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Re: Smallest 486 MOBO I've seen

Posted on 2013-07-12, 09:36

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

This work reminds me of the cache rework I did on my HOT-433 v4 board. It came with single-banked 256K soldered on, it was real cache though. The jumper selector header had solder wires, so I also had to solder in jumper headers. Worked fine after the mods, but it makes me wonder why the MB maker …

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Re: Smallest 486 MOBO I've seen

Posted on 2013-07-12, 01:43

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You can even still buy some new, old-stock DIP-32 sockets for this project. http://www.ebay.com/itm/221119045395 Aside from the decoupling caps, you'll probably also need to figure out what missing jumpers there are to set the cache size - 256K or 512K. The jumper header may not even be on the board …

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486 support for 1K, 2K, 4K, 8K memory refresh rates

Posted on 2013-07-12, 01:29

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by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

A good article on memory refresh can be found here, http://www.oempcworld.com/support/2K_vs_4KRefresh.htm Does anybody know what refresh rates are supported by various 486 chipsets? The total capacity of the SIMM also seems to come into play with what refresh rate is supported.

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Re: AT PSU +5V pin overheating at motherboard

Posted on 2013-07-11, 23:23

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The DTK PKM-0033S doesn't use the UM8881/8886, it uses a SiS 496/497. I've been working with this board over the past few days. I have hacked up the Zida Tomato 4DPS BIOS v1.72f to work on this DTK board. Now the DTK board seems to work with two 64 MB FPM sticks, 1024K, fastest timings, AMD X5-160. …

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Re: AT PSU +5V pin overheating at motherboard

Posted on 2013-07-08, 20:48

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Switching to a different AMD ADZ CPU didn't help. Some time ago I had an Intel DX4 CPU inserted incorrectly for some 15-20 seconds (in a different motherboard). The smell was horrible. The CPU survived and works well but the MB was dead. Something has happened to this DTK board. It was not a fluke …

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Benchmark results for interleaved L2 cache

Posted on 2013-07-08, 13:17

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Does anyone have any benchmark results which indicate any benefit from double-banked interleaved asynchronous L2 cache vs. single-banked non-interleaved cache?

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Re: AT PSU +5V pin overheating at motherboard

Posted on 2013-07-08, 12:28

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

And the plot thickens! 512KB L2 only works with the AMD X5-160 w/fastest BIOS settings when using double-banked UMC-branded cache. Winbond 15ns and 10ns causes HIMEM errors, but UMC passes without issue. This is very repeatable. Still, ISSI 1024KB works fine with AMD X5-133 using the fastest …

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Re: AT PSU +5V pin overheating at motherboard

Posted on 2013-07-08, 07:12

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I tried removing the other 5V pins to let the pin P9.6 heat up again, but 1024K, 40 MHz, fastest timings failed HIMEM still. The only other item of suspicion for why 1024K, 40 MHz, fastest timings no longer passes HIMEM could be because I accidently inserted the CPU in the wrong orientation for …

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Re: The Ultimate 686 Benchmark Comparison

Posted on 2013-07-08, 03:00

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by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I beleive I tried this on the 430TX board, but I couldn't get it stable past 262 MHz. You'll have to use the 300 MHz results for the P1 MMX on the VIA MVP3 board as an approximate substitute. It is unlikely I will make any additions to this comparison anytime soon, but when/if I do, I'll try to add …

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Re: AT PSU +5V pin overheating at motherboard

Posted on 2013-07-07, 22:45

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well, the board does work well with 256KB cache, the fastest settings, and AMD X5-160 - it is 1024KB cache and the fastest settings which now are not happy with the cooler PSU connector. I've had trouble with SiS 496/497 boards working with 1024K, fastest timings, and AMD X5-160, but this particular …

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Re: AT PSU +5V pin overheating at motherboard

Posted on 2013-07-07, 12:20

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Mystery solved. I removed all the connectors from P8 and P9. The red 5V pins looked like the first attached photo. They springiness of the connector is gone. I used pliers to re-bend the connector. The connector will probably flatten again as this PSU is my AT test-all supply. Anyone know the part …

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Re: Just an important heads up

Posted on 2013-07-06, 21:45

by

by feipoa

in Milliways

in Milliways

Is there no longer a feature to update an attachment when you edit your post? This feature was nice as it didn't require a view counter reset.

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Re: Just an important heads up

Posted on 2013-07-03, 22:25

by

by feipoa

in Milliways

in Milliways

Bullet points from the old site do not seem to display correctly on the new site. They now appear as •.

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Re: Shuttle HOT-433 with 1 MB cache

Posted on 2013-07-03, 20:42

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have had nothing but problems trying to get my money back from eBay member 1-800-4-memory for their 3.3V memory advertised as 5V. I'm not sure if this forum has a thread for eBay members to watch out for, but this seller might go on such a list. They don't check their part numbers before shipping, …

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Re: Shuttle HOT-433 with 1 MB cache

Posted on 2013-07-01, 20:51

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by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I used 3.3 V EDO SIMMs which had the double-diode down regulation on an M919 for 2 years without trouble. I measured the voltage across the actual chips while it was turned on and it was 3.3 V.

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Re: Shuttle HOT-433 with 1 MB cache

Posted on 2013-06-30, 19:43

by

by feipoa

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I will be surprised if you can find the UMC 8881/8886 manual. I've looked for this off and on for years. My EDO SIMMs have 8 chips. The partial IC pull-up method you describe requires too much effort and uncertainty. I'd probably rather mod 1 particular motherboard these chips would go into. I do …

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