Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-15, 19:14

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I used to have something very like this: https://dirtypcbs.com/store/designer/details/ … -breakout-board But I lost it!! 🙁 Now I just use little gold pins stuck in the back of the ISA slot contact spring.

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-15, 15:41

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yep, I'll post up details of the things I try with the benchmarks. Also, I don't know if anyone can shed any light: the FLUSH hardware mod for some motherboards... Do you think I'd require it? I enabled the FLUSH register... didn't seem to do much but then it might not with the benchmark pack... …

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-15, 13:42

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Welp, it's been running fine since yesterday, hardly even warm to the touch. It did NOT like being overclocked to 40Mhz base frequency: ran fine in single speed mode but activating clock doubling with that overclock made it fall over. That's OK, I just was curious to try. :) I'd also forgotten, just …

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-14, 19:53

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looking pretty good there!! Now just have to play around setting registers to get the cache and the clock doubling working. Wonder if there's a way to hard code that into the bios ROM 🤔

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-14, 00:47

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah I inspected with a microscope also, but, like I say - under that socket is a hidden world of forbidden mystery! I put the interposer back in and powered up, no explosions with and without a speaker connected. I figure maybe it was KEYLOCK... only thing I can come up with... if it was anything …

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-13, 22:38

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Heres the cpu in question, attached. 3.6v. I -think- this is the 3v jumper option? I've read this thread until my eyes spin and there's no collected documentation, so hopefully that's the case? There is some confusion for me, because this IS a sxl2, which I read should have the 5v jumper set... and …

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-13, 19:23

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Speaker circuit still works. After enough current to MELT that cable, it still works. Da. Fuq? 🤣🤣 K I'm going to wait to see if anyone has any thoughts before I go back to this RN 🤔🤣

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-13, 19:20

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well mixed results. At first I had the jumper set for 5v, all was OK with just the interposer in the motherboard... Realised my cpu was 3.6v, so flipped the jumper over for 3v operation. Installed interposer, switched on machine to read voltages and set trim, and the PC speaker cable burst into …

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Re: ABC COMPUTER COMPANY, LTD. A3286 / A3886-01 V3.0 - repair thread

Posted on 2023-09-13, 01:47

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by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've had luck removing pin oxidization with Silvo (liquid silver polish) and in some odd cases Brasso (same deal but made for brass). Might be worth a go?

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-12, 23:34

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Right, finished this today and I'll give it a test tomorrow. I can say with certainty that this was a complete bellend to build: not for the beginner! In the event I ever build another, hot air or reflow oven with solder paste only for me. It could be made easier by taking the sockets and throwing …

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Re: ATX to AT pico Adapter! + Fan Headers Soft on/off, -5v, and 3.3v (Released)

Posted on 2023-09-09, 14:05

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

On the question of latching logic for power on, I took an old fashioned approach with mine: I replaced the momentary switch on the case with a latching one of the exact same dimensions (50cents from AliExpress) and fed those wires to PWR_GD. https://a.aliexpress.com/_mN1I0qQ Works perfect, the …

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Re: The million dollar question on retrocomputing

Posted on 2023-09-06, 15:21

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by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

aries-mu wrote on 2023-09-06, 15:19: Wait what? What's this? Is this what I think it is???? 😳 Please!!!!! All looks very, very early stage, but my fingers are crossed: https://github.com/skiselev/sandy_river_486

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Re: The million dollar question on retrocomputing

Posted on 2023-09-06, 15:16

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by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm eagerly awaiting Sergey's new 486 board I think he's working on right now.

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Re: Crystal for MEGATRENDS MEGA-KB-H-WP

Posted on 2023-09-06, 15:02

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by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Some datasheet goodness for the Chipset: http://www.bitsavers.org/components/opti/data … pset_199108.pdf I noticed a lot of even the big-name motherboards of the era are pretty much identical to the suggested build in those manuals. Hope that helps!

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Re: Searching for small microATX case

Posted on 2023-09-05, 12:31

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by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Maybe after that we're talking about industrial cases? There were some rail mount ones I saw a while ago that had room for the mobo and very little else. Not exactly good looking though lol! When modular PSU's started to get popular I was waiting for proper modular cases: you know, tiny cases for …

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Re: Gainbery MAXimizer Cyrix 5x86-133

Posted on 2023-09-03, 16:59

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Interesting little bottom pins for the socket adapter. I wonder if those little holes allowed hot air jets to solder it all together in production?

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Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-09-01, 12:35

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Awww, I ran out of pins for just now. Getting there on the first experimental one though! Inter Start.jpg Some things I've done / noticed: * I used another spare PCB to hold the pins in alignment for soldering: this actually worked pretty well and saved me having to buy the smaller PGA socket as a …

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Re: Swap S3 virge dx bios chips between different brands of cards. Is that possible?

Posted on 2023-08-24, 15:09

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by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I think it's unlikely you'd break the card. If it was me and the EPROMS were the same pinout, I'd just swap it in and see if it POSTS. Only thing I'd watch for is if you are using a much older CRT, plug it into the VGA port and if you don't get a picture unplug it quickly: just on the 10000000:1 …

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

Posted on 2023-08-23, 16:58

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by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I took a quick look over my NuXT PC build with a view to selling it. I've got a floppy drive to replace as it reads its own disks OK but no one else's. I think alignment of the heads is probably at fault and that's not a job I'm going to do on a HD 3.5" drive! lol I also tested the AT to PS2 PCB I …

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2023-08-17, 16:18

by

by ChrisXF

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah I was about to say, looking at Max's schematic everything that's not directly related to the mouse support is passed through perfectly. You'll need to have a dig around the turbo circuitry and try and figure out exactly how the keyboard controller is flipping turbo on and off. Could it be using …

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