Re: Generating ~4v on 486 motherboard for overclock?

Posted on 2021-05-16, 15:43

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Adjusting the input voltage wont change anything as the voltage regulation circuit will regulate it to 3.3v (or 5v). On 486 boards the voltage regulator does not always extend beyond the cpu AKA ISA, Memory and other motherboard components are many times run right off the tap even if the CPU is on …

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Re: Generating ~4v on 486 motherboard for overclock?

Posted on 2021-05-16, 08:50

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Disruptor wrote on 2021-05-16, 08:22: Have you also tried the 3.6 V setting (used for some Cyrix CPUs)? No 3.6v setting - only 3.3v or 5v

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Re: Generating ~4v on 486 motherboard for overclock?

Posted on 2021-05-16, 07:28

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

4v is a little high for a mild OC, I would start at 3.6-3.8 (even 3.5 if it’s there) My experience is that if it’s unstable at 160mhz with a small amount of extra voltage it’s either 1. Motherboard/Cards don’t like 40mhz 2. Memory or Cache doesn’t like 40mhz 3. Inadequate Cooling 4. Motherboard/PSU …

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Re: Generating ~4v on 486 motherboard for overclock?

Posted on 2021-05-16, 07:23

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

An AMD 5x86 133 (4x33) should be overclockable to 150 (3x50) or 160 (4x40) MHz without overvolting. You'd better try to continue your experiments by under-over-clocking to 120 MHz (3x40) to find out whether your motherboard runs flawless with a 40 MHz FSB or requires some waitstates. Do not forget …

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Generating ~4v on 486 motherboard for overclock?

Posted on 2021-05-15, 19:39

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi, I'm trying to get a AMD 5x86 133 to run at 160MHz I can post and get to dos etc but once start stressing the CPU eg playing duke3d for more than a few seconds, it crashes. My motherboard (model number in signature) supports 3.3v and 5v via a jumper. I wanted to try and get a slight over-volt to …

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Re: WebOne - proxy for old browsers to make them Web 2.0-capable

Posted on 2021-04-25, 18:11

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by squelch41

in Release Announcements

in Release Announcements

I think this feature will be good and easy to implement. But currently I have too small free time to work even on major functionality, so I am not planning to add POP3/SMTP/IMAP support in nearest releases. The project is open source, and any contributions will be greatly appreciated. Just wanted …

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Re: 486 Won't boot, not a Beeb

Posted on 2021-03-07, 14:44

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The chip near the ISA slots labelled mb300-e is probably the keyboard controller

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Re: Cheap HDD alternatives for old Hard disk drives in 486

Posted on 2021-03-07, 14:40

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I use a CF-IDE adapter as they're cheap and passive devices so less to go wrong

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Re: A noob and XT-CF Lite woes

Posted on 2021-03-03, 20:48

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Murugan wrote on 2021-02-26, 16:02: I can make an image and write it to the card,i can access the card in my desktop but in the xt it says missing operating system. I've looked up how to flash it but I seem to postpone it 😀 You really should try flashing the firmware. The version you are using is …

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Re: A noob and XT-CF Lite woes

Posted on 2021-02-24, 23:44

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

First thing I'd do is update the xtide rom http://www.xtideuniversalbios.org/binaries/ Make sure you run the configuration utility before you flash it. Presume you arent only using large (>4Gb) CF cards as have seen people reporting problems with them? If so, might be worth getting a small (1gb or …

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Re: Mod a Micro ATX Case --> Baby AT Case

Posted on 2021-02-13, 11:42

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I find lots of micro ATX cases in good shape and some full size ATX cases which I need for the full size ATX boards, but the baby AT cases don't show up very often any more. Yeah, that's why I went with a mATX case - AT cases not too easy to come across and prices on ebay, esp with shipping, just …

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Re: Mod a Micro ATX Case --> Baby AT Case

Posted on 2021-02-12, 22:28

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Works well How did you do the power? Did you refit the case for an AT power switch or did you use an ATX power with adapter and use the existing power switch? I used an atx supply with an atx-at adapter. Swapped out the switch in the case button from a momentary switch to a latched switch (just …

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Re: Mod a Micro ATX Case --> Baby AT Case

Posted on 2021-02-10, 21:06

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

my 486 baby-AT board is in a micro-atx case - just bought a blank io shield to cut a hole for keyboard connector and cut holes to mount serial ports in. Drilled holes in the right places for standoffs in the motherboard try. I had 3 cards and then used the last slot to mount a CF-IDE backplate so …

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Dot matrix printer and CUPS problem

Posted on 2021-01-31, 15:50

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi, I'm using a panasonic kxp3626 dot matrix printer. Connected through a USB to parallel adapter on windows 10 using the panasonic recommended epson LQ series (136) driver it works fine. However, I really want to have it connected to my raspberry pi so it is accessible on my network (my pi is a …

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Re: DB25 networking

Posted on 2020-12-07, 12:22

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Quick google I found and article from someone in NHS IT saying 25 years ago NHS was mainframe and green screen based so keep in mind this is very different setup to a PC based network. The sever would look closer to those big as a fridge reel to reel servers from 60's movies then a PC with a bunch …

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Re: DB25 networking

Posted on 2020-12-04, 20:59

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Theres several protocols that often use the DE25 connector. Its hard to guess how it was utilized in the facility you reference. RS232 would be point to point and would probably have an endpoint computer with a ton of RS232 ports like you suggest. Such serial hubs do exist. More likely is RS422 or …

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DB25 networking

Posted on 2020-12-04, 19:16

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I work in the NHS and older buildings often have old female db25 ports in the wall that were used for networking - think they were used for the EMIS LV GP IT system before the servers moved to cat 5 or vt-100 type terminals for connecting to hospital lab servers. Were these point to point serial …

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Re: hdd replacment - sd card, cf card or scsi

Posted on 2020-11-25, 11:09

by

by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

CF to IDE works well in my 486 and is pretty straightforward plus came with mounting bracket. Only issues I had was the bios correctly detecting drive geometry but that was solved by xt-ide bios (it may well have been to do with the fact I dont have a floppy drive and had formatted the cards and …

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-25, 10:01

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

(so wire to vref pin and then a ground point - avoid soldering on the board)

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-24, 10:13

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Okay, here's the relevant bit from the datasheet: LM431.jpg Vref is a fixed 2.5V. I think R5 (1.2Kohm) and R15 (3Kohm) from your board correspond to R1 and R2 on the above schematic. If I'm right, replacing R5 with a 1.5Kohm will yield a voltage of around 3.75V, or 4 volts when using 1.8Kohm. Or …

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