Posts

Showing posts from April, 2021

486DX2/80 Build - When You Have Lemons, You Make Lemonade

Image
I mentioned in my 486 Pentium Overdrive blog post that I had gotten a 486 motherboard that did not work out for that project. The motherboard had actually come out of an arcade machine from a company called Lazer-Tron. There was no documentation to be found, so finding jumper settings for the CPU would be a next to impossible task. I put the motherboard aside thinking I probably was not going to use it anytime soon. Time passed and I was doing some reading on Cyrix CPUs. Cyrix did not manufacture their own processors, they contracted IBM, Texas Instruments or SGS Thomas to do that. Part of the licensing for these companies was that they could produce these CPUs under their own branding. So if you see a 486 from one of these 3 companies, it's really just a Cyrix 486. That motherboard came with a SGS Thomas 486DX2-66. I had Cyrix 486DX2-80 from another project. While I could not change the jumpers for the CPU, the jumpers for FSB speed and voltage are silk screened on the motherboard

The Legality Of Using Old Software In Modern Times

Image
Is it in fact legal to use old software without paying for it? In the strictest legal sense the short answer is no. This is evidenced by the fact the companies like Nintendo guard their intellectual property very closely, going after sites distributing copies of their old console games going all the way back to the original NES console. Other companies turn a blind eye to the whole matter. I don't see Microsoft going after people using a copy of MS-DOS. They are well beyond that OS and are firmly focused on Windows. Retro computing is a growing in popularity and it may prompt some companies to take a second look at their old offerings and adopt a policy like Nintendo. I really don't see that being the norm, but rather the exception.  There is a concept in Retro computing called Abandonware. This falls under turning a blind eye notion  The software may still be under copyright, but the owner of that software is not actively pursuing a legal course to protect it. The vast majorit

Cyrix MediaGX - The World's Fastest 486 In A Socket 7 Package

Image
I wanted to build a Cyrix 5x86 system as that was one CPU I never owned. I was watching the CPU Galaxy channel on YouTube and he covered a Cyrix MediaGX build that he had done. I remember this processor and had actually worked on few systems with one many years ago. A little background is in order. The Cyrix 5x86 was a stripped-down version of their 6x86 CPU. They took about 50% of a 6x86 and got about 80% of the performance putting it into a 486 package. It was one of the fastest 486 upgrades out there. When Cyrix was purchased by National Semiconductor in 1997, they decided to focus on low power, embedded systems. The result was the MediaGX. It is a System On A Chip (SOC) containing a Cyrix 5x86 CPU core, memory controller, video controller, and a Sound Blaster 16 compatible audio controller. They were mostly used in notebooks and embedded control systems. There were not many motherboards for end users to put them in their systems. The CPU Galaxy video linked to seller on eBay sellin

486 Pentium Overdrive - Third Time Is The Charm

Image
When I got back into retro computing, I had a number of computers I wanted to recreate that I had in the past. One of those was a 486 computer upgraded to a Pentium Overdrive CPU. I found a 486 computer on Craigslist for only $50. I purchased it along with the $20 Pentium 133 system I wrote about a few posts ago. Unfortunately, the motherboard had a standard 168 pin 486 CPU socket. I forgot a Pentium Overdrive CPU requires 238 pin Socket 2 or 237 pin Socket 3 motherboard and so strike one. I ended up selling that motherboard to a friend for his own 486 build. I next purchased a 486 Socket 2 motherboard from eBay. Although the Pentium Overdrive worked in this board, it performed well below what it was supposed to. I later found out the motherboard came out of an arcade machine and there was no documentation to be found anywhere on the jumper settings for the CPU and so strike two. I ended up using that motherboard in 486DX2/80 build and it is working fine for that. Finally, I did my hom

Tandy 1000 TL/2 - Having Your Cake & Eating It Too

Image
The Tandy 1000 was the first computer that I owned. I have very fond memories of it going all the way back to 1985. It is no wonder I own 5 of them in total. My Tandy 1000 TL/2 is what I am going to cover today and what makes it unique from all the other Tandy 1000s I have. In 1988 Radio Shack released the Tandy 1000 SL & TL computers. These had several enhancements over previous models. The graphics could now go all the up to 640x200x16 colors on a standard CGA monitor. It had a DAC for recording and playback of digital sound. MS-DOS 3.3 was included in ROM for almost instant booting of the computer without need for a floppy diskette. The keyboard connector was now a standard DIN5 keyboard connector and Tandy included an Enhanced 101 keyboard. System setup was done with a separate program that saved the system configuration to an EEPROM. The TL could be upgraded to 768K of memory. The extra 128K was then used for video memory freeing the lower 640K for DOS and user programs. The T

The Little Known Epson Equity Ie - An IBM PS2 Model 30 Clone

Image
I have always had a fascination with 8086 XT class computers. Mainly because there were so few of them compared to the multitude of 8088 XT class computers out there. I own a Tandy 1000 SL with an 8MHz 8086 CPU (upgraded to an NEC V30). This is much faster than my Tandy 1000 SX with a 7.16MHz 8088 CPU (upgraded to a NEC V20). I have always wanted a 10MHz 8086 based system. These are as fast as you can officially go with an 8086. Intel only made them to run up to 10MHz. I had been keeping my eyes open for quite some time when an Epson Equity Ie came up for sale on eBay. The computer was in excellent condition and I ended up buying it. This is the only computer I know of outside of IBM’s PS2 Model 25 & 30 that have MCGA graphics onboard. This is basically a cut down version of IBM’s VGA chip. It only has 64K of ram vs 256K for the VGA. It supports the 320x200 256 color mode of the VGA as well as 640x480 2 color mode, but none of the VGA’s 16 color modes. This makes it pretty useless

Turning A $20 Craigslist Purchase Into A 500MHz Gaming Powerhouse

Image
Last year I picked up a couple of computers as part of a Craigslist purchase from a local seller. One the computers cost $20 and was described by the seller as "nothing special". It had a PC Chips M572 motherboard with an i430TX chipset, Pentium 133MHz CPU, 40MB of ram, 40GB hard drive, 1.44MB 3.5 floppy drive, DVD drive, 8MB ATI RageXL PCI video card and a low end Ensoniq PCI sound card. I was originally going  to take the motherboard out, but there was something about that motherboard that I remembered it could be upgraded with a much better CPU. I checked online and there was indeed a patched BIOS available to allow for the use of a K6-2+ or K6-III+ CPU. I download the patched BIOS and applied the BIOS update to the motherboard. The M572 motherboard has PnP CPU setup in the BIOS. There are no jumpers to set. This makes for easy changes to the motherboard. You can set the voltage from 2.0 to 3.5 volts, FSB speed of 60, 66, 75, or 83 MHz and CPU multiplier of 1.5 to 5.5. I