Re: Need help identifying purpose of unknown ISA card

Posted on 2021-07-14, 10:20

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I was thinking more about the one on the card, the M2764AFI with the SCA-TCJ sticker on it. Looks like it's socketed, so if you have access to a programmer then you should be able to remove it from the card and read the contents.

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Re: Need help identifying purpose of unknown ISA card

Posted on 2021-07-14, 09:25

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Any way of dumping the EPROM contents to see if there are any text strings that might give a clue? Also there's what looks like a bit of text along the top of the card that I can't make out, does that give any hints? Filename placa1_PCB_Text.jpg File size 55.05 KiB Views 217 views

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Re: Voltage fluctuations on ASUS P5A-B

Posted on 2021-07-04, 07:56

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've had a motherboard that reported voltages with a fixed offset, but not seen one with swings like that. Do you have a second PSU you can compare with? It might be difficult to check for a noisy supply with a multimeter. I know that my cheap meter is quite slow, so it averages the voltage and will …

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Re: Need help identifying old PC gamepad

Posted on 2021-06-30, 18:43

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Gravis Xterminator has a throttle (image from http://www.tweak3d.net/reviews/gravis/xterm/): Filename 2.jpg File size 46.33 KiB Views 123 views

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Re: CMOS battery on a Compaq Presario CDS 520

Posted on 2021-06-30, 07:37

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ah. Yes. That makes more sense. You mean just plugging something like this: https://www.smallbattery.company.org.uk/sbc_840.htm on to the obvious header marked 'battery'? I was obsessing about changing the battery so didn't even notice that. I expect the motherboard has diodes to protect the …

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Re: CMOS battery on a Compaq Presario CDS 520

Posted on 2021-06-29, 21:54

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sounds like cutting the old one out and adding one of these might be the best option. Not sure why it has space for 2 batteries though. https://www.amazon.com/LAMPVPATH-cr2032-Battery-Holder-CR2032/dp/B07BXDHT4B/ref=sr_1_6?dchild=1&keywords=cr2032+battery+holder&qid=1625002958&sr=8-6 I think that …

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Re: CMOS battery on a Compaq Presario CDS 520

Posted on 2021-06-29, 21:38

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looks like it might be something like this: https://uk.farnell.com/panasonic-electronic-components/br-2330-gun/battery-lithium-3pin-horiz-br2330/dp/1298256 In which case, I think it's spot welded to the carrier, so you'll probably have to unsolder the current one. Or maybe just cut the current …

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Re: AT to PS/2 keyboard adapter differences causing KVM keyboard error?

Posted on 2021-06-29, 21:32

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So the KVM PS/2 connector only works in one of the AT to PS/2 adapters? But all other combinations of keyboards and adapters work ok? Maybe there's some pin/socket dirt/corrosion problem that lines up just wrong with the problem combination? Did you also check if the unused pins and the shield are …

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Re: CMOS battery on a Compaq Presario CDS 520

Posted on 2021-06-29, 21:03

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looks like it might be something like this: https://uk.farnell.com/panasonic-electronic-components/br-2330-gun/battery-lithium-3pin-horiz-br2330/dp/1298256 In which case, I think it's spot welded to the carrier, so you'll probably have to unsolder the current one. Or maybe just cut the current …

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Re: Retention Arm Replacements for Slot A/1 CPUs?

Posted on 2021-06-29, 20:43

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

One downside is that the outside metal rods aren't the same as the inner ones, which have an inner gap for e-clips to "clip" onto. With 1mm thermal pads, with only the center four rods acting as retention mechanisms, this results in the CPU card doing a bit of a bend. :/ I can't imagine it being …

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Re: New PSU on a AMD Athlon build?

Posted on 2021-06-29, 06:53

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Current requirements might depend on which motherboard you're using. I've got an Abit KA7 Slot A which (from memory) uses +5V as the input to the CPU voltage regulators, then uses the +12V to supply an on board 3.3V regulator, which is used for all the 3.3V on the board, and also for the input to …

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Re: New PSU on a AMD Athlon build?

Posted on 2021-06-28, 21:05

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Current requirements might depend on which motherboard you're using. I've got an Abit KA7 Slot A which (from memory) uses +5V as the input to the CPU voltage regulators, then uses the +12V to supply an on board 3.3V regulator, which is used for all the 3.3V on the board, and also for the input to …

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Re: Tandy 1000EX external floppy pinout

Posted on 2021-06-24, 06:35

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looking here: ftp://ftp.oldskool.org/pub/tvdog/tandy1000/documents/cables.txt There's a section on floppy drives that looks useful, and in particular it gives the pins on the tandy connector that carry power. +5V on 3,5,7,9,11 and +12V on 29,31,33. [editing to add the following after realising I …

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Re: Checking unexpected interrupt and stuck NMI - Failed

Posted on 2021-06-20, 19:45

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well I checked the connections from the 74ALS245 lead to the various chips and everything is ok. Since I have two identical motherboards, I started a parallel measurement of the various pins with respect to the ground, and I immediately realized that the problem is much more complex, since the …

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Re: [repair advice] Gigabyte 5AA Rev 2.2

Posted on 2021-06-19, 20:08

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The burnt trace from the via (that is near L3) provided, protected by the FS1 fuse Ha, looks like L3 blowing protected the fuse then, I'd like to know what value that fuse is. There must have been several amps flowing to cause that much damage to L3 and surrounding tracks. Sounds like a good …

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Re: [reapair advice] Gigabyte 5AA Rev 2.2

Posted on 2021-06-18, 21:40

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Found an ebay image of the board unburnt: Unburnt_5aa.jpg Looks like as well as burnt surface tracks there's some burn marks on the PCB surface between the 'L3' silkscreen mark and the AT power connector, might indicate an internal track got a bit hot. Does the LPT port work ok? Component might be a …

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Re: I recently found this hardware, AKA the Dumpster find thread.

Posted on 2021-06-14, 17:20

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

K7T Turbo - too late to recap? Excellent condition minus the caps... IMG_3194[5596].jpg Looks like a bit of dust around the CPU socket that would be good to clean up. It's probably down draft from cooling fan. Can't see any obvious corrosion so you might be ok. Looks in better condition that a Slot …

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Re: I'd like to introduce my new computer buddy.

Posted on 2021-06-13, 11:50

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Shreddoc wrote on 2021-06-13, 08:13: Dunno why but he reminds me of Ed Sheeran. The Serpent Rider wrote on 2021-06-13, 08:27: Eventually it will consume your soul. You should consider killing it with fire. Seems a little harsh on Ed.

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Re: I am looking for ideas on what 5.25 floppy disk drive to get

Posted on 2021-06-10, 22:28

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

5.25 Drive has arrived and installed it but for some reason the computer will turn on but won't boot or post? I do hear the PSU Fan is spinning and feel air coming from the back of the case where it is so I don't think it is the PSU but did change the CD drive to newer one though while I was at it. …

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Re: I believe I broke my Socket 7 motherboard, advice needed

Posted on 2021-06-08, 21:35

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

These things happen sometimes. After finally tracking down and fixing the actual cause of a fault on a cd drive a few months ago, I got it all reassembled, then got careless (end of long day excuse) and managed to plug an eprom in the wrong way round; that didn't go well (disappointing lack of smoke …

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