Re: Looking for PCjr Sidecar 512k hack instructions

Posted on 2023-10-10, 15:48

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

pentiumspeed wrote on 2023-10-09, 22:58: To get full compatibility, you'll need to finish missing items that PCjr were missing with. DMA is one of these. Cheers, Yeah, the PCjr is quite a quirky machine for sure. But that's why I find it fun and interesting

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Re: Looking for PCjr Sidecar 512k hack instructions

Posted on 2023-10-10, 15:20

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

BitWrangler wrote on 2023-10-10, 02:05: Pile of Junior mods here, 640k mod near the top, bit hard to read.. http://etc.pixesthesia.com/jrstuff/ Still haven't found that site where the dude had a load of new old stock PC Jr stuff for sale also, thought he had mods and guides. Great resource, thanks! …

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Re: Looking for PCjr Sidecar 512k hack instructions

Posted on 2023-10-10, 14:30

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So far all I have been able to find is this from - PCJr Power by Albert L. Allen * copyright 1989 * IBM 128K MEMORY SIDECAR UPGRADE TO 512K If you have a PCjr with a attached 128K memory sidecar you can upgrade that sidecar to house a full 512K of memory. Bringing your junior to full 640K. WARNING: …

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Re: Looking for PCjr Sidecar 512k hack instructions

Posted on 2023-10-09, 19:29

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Brutman.com has forum you can ask on or I might have the links to some old PCJr newetters that I think have the instructions. Memory serves me the IBM takes more modification then just replacing the chips, the Tecmar Jr Captains I have just require replacing the chips and that's it. Thanks, I have …

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Re: Looking for PCjr Sidecar 512k hack instructions

Posted on 2023-10-09, 19:27

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

BitWrangler wrote on 2023-10-09, 17:04: Lost the site I was thinking of, but found this one, don't know if it gets you any closer... https://www.brutman.com/PCjr/pcjr_mods.html Thanks, that's how far I got. It doesn't say if It can be done with my original IBM sidecar. I hope it does!

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Looking for PCjr Sidecar 512k hack instructions

Posted on 2023-10-09, 16:11

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi, If I'm not mistaken, it's possible to hack a 128k sidecar to take 512k. Does anyone here know where I can find the instructions? Thanks!

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Re: Looking for Compaq presario 425 / 433 recovery disks

Posted on 2023-05-24, 13:34

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by epictronics

in Marvin \ Software

in Marvin \ Software

Now I'm looking for these restore floppies too :) I just dug out my 433 out of storage for a full restoration. There is a file on the internet archive page but it looks messed up and doesn't seem to be made from the original restore disks. I'm pretty sure it used the same set of disks as the more …

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Re: IBM PS/1 2155-593 Restoration

Posted on 2023-05-18, 21:05

by

by epictronics

in Marvin \ System Specs

in Marvin \ System Specs

Hi guys, very interesting thread, i have a tower IBM 2168-552, 25mhz locked, take a picture too R176 Populated R174 & 75 NOT I have a overdrive DX4/75mhz (3x25) and i will LOVE to overclock to 100mhz (3x33) IBM.jpg I just finished the video about this hack. It will go live on Saturday : )

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Re: IBM PS/1 2155-593 Restoration

Posted on 2023-05-18, 12:07

by

by epictronics

in Marvin \ System Specs

in Marvin \ System Specs

Holly smokes, I'm doing some tests now, we're doing pretty good!

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Re: IBM PS/1 2155-593 Restoration

Posted on 2023-05-14, 07:47

by

by epictronics

in Marvin \ System Specs

in Marvin \ System Specs

Thermalwrong wrote on 2023-05-13, 23:08: This is only my guess at the moment but the lines match up too well. I think the R174 - R175 - R176 are the solder/component jumpers to specify the PLL frequency. You have a sharp eye! The board is on the bench, let's give this a try : ) Thanks!

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Re: IBM PS/1 2155-593 Restoration

Posted on 2023-05-13, 22:25

by

by epictronics

in Marvin \ System Specs

in Marvin \ System Specs

I'm working on a PS/1 2168 and the board looks identical to the board in this thread. ... Could you get a closer in shot of the area around the 14.3MHz crystal without the CPU power wires in the way? That's where the PLL is so it makes sense to look there first. It looks like the SPxxx things are …

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Re: IBM PS/1 2155-593 Restoration

Posted on 2023-05-12, 07:44

by

by epictronics

in Marvin \ System Specs

in Marvin \ System Specs

I'm working on a PS/1 2168 and the board looks identical to the board in this thread. However, my board is set to 25Mhz and there doesn't seem to be a jumper to change it to 33Mhz. The only difference I can spot int the picture is that the board in this thread has a jumper connected to j27 That's …

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Re: 286 Acer 915P (N) showing and few questions

Posted on 2023-01-15, 19:02

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Old thread, but there probably aren't that many of these boards out there, so one thread here is probably enough to rule them all : ) Apparently, my Canon A-200EX II HD20 has a very similar board to this Acer 915p (N) board. I'll post a few pictures in case they are useful for someone

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Re: Help me identify this Graphics card (EGA?)

Posted on 2022-12-10, 22:25

by

by epictronics

in Marvin \ Video

in Marvin \ Video

Thanks for the warning. It seems I made a good choice not to test the card blindly. I'll do some tests with the scope while trying out the switch block settings for the IBM EGA card. Many thanks

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Re: Help me identify this Graphics card (EGA?)

Posted on 2022-12-10, 21:31

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by epictronics

in Marvin \ Video

in Marvin \ Video

Thanks Is it safe to connect an IBM MDA/CGA/EGA CRT if I get the switches in the wrong position? I have not tested the card because I don't want to risk damaging my displays : )

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Help me identify this Graphics card (EGA?)

Posted on 2022-12-10, 20:27

by

by epictronics

in Marvin \ Video

in Marvin \ Video

Hi all, I have an unidentified graphics card in my collection. I can't use it because I don't know how to set the switch block. Anyhow, I just watched the 8-bit guy's "super CGA" video and It's very similar to his EGA Wonder 800. Does anyone know what this card is?

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Re: Beneath a Steel Sky CD - Roland music + SB Speech

Posted on 2022-11-29, 14:34

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by epictronics

in DOS

in DOS

Bump. I just pulled my CM-64 out and realised this issue. This game really deserves a patch if anyone can do it

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Re: How to identify this 486 motherboard techmedia UMC um8498F

Posted on 2022-06-05, 23:31

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by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have had my fair share of chip swapping 😀 I always practice on scrap boards first before I try something new. https://youtu.be/Ah9Rh1xxWn0 Thanks for the info about the 5429, that could come in very handy and a fun project to try : )

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Re: How to identify this 486 motherboard techmedia UMC um8498F

Posted on 2022-06-05, 07:07

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by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I did have to deep-six a GD5429 for being very glitchy earlier. It's possible the chip itself is faulty. :( Oh well, makes a good excuse to swap a '5429 in its place, right? XD All you need is a hot air station and a known good GD5429 chip. (Or SMD removal alloy and a ton of SMD flux and two tons …

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Re: How to identify this 486 motherboard techmedia UMC um8498F

Posted on 2022-06-05, 07:05

by

by epictronics

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Are you using the onboard graphics? Have you tried to see if it behaves differently with other graphics cards? If the problem disappears with other graphics cards, I would swap the onboard VRAM chips next. So i moved on to test with ide disk today ;) for some reason its the shareware version that …

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