This thread is awesome! I found it when doing a search on upgrading the Mega PC with a 486slc..
I bought a Mega PC back in 1993 when the price was cut to £599. I'd lusted after one for some time but the £999 price was too high.
I was shocked to find that it couldn't run some games any better than my Amiga CDTV. The machine was ridiculously crippled (for a PC), but I never realised back then when I bought it... I thought I was getting a rather powerful 25MHz machine with the ability to display 256 colours.. much higher than my Amiga..
I upgraded its RAM to 4MB and VRAM to 512KB and also put a Soundblaster pro in to get effects in PC games.. this caused issues with the MD card so I had to disable it when using SB.
I eventually had a machine that I very much enjoyed playing games on... Wing Commander, Monkey Island 2 (without all the disk swapping!) And Wolfenstein 3D to name a few. I also played Sonic to death on the Megadrive side.
Only about 6 months after, though, I felt stuck with the machine and wanted to do more... the advice from my local Amstrad dealer was to upgrade to 486... back then that meant getting a new machine at a very high cost (I never knew about the clip on upgrades)... I was a bit miffed and decided to sell it all and get an Amiga 1200... I still have that machine to this day and love it (I've made some rather crazy mods to it that I posted on Amibay some years ago).
The thing is, I really liked the idea of the Mega PC. I found out about the teradive in Japan which looked really awsome in black (reminded me of my CDTV) and for a while hoped that a more powerful version would appear... It never did..
Roll on 5 years later, 1998/9 i'm at a car boot sale and guess what I see?... A Mega PC all complete with monitor etc all looking in almost new condition for.... £5
I casually bought it, my face looking cool... but inside I was like.. OMFG!! Gotta run away with this fast before the guy realises!.. it was heavy.. so I walked very fast instead 😁
By this time, I had collected quite a few machines, one being a Mega CD which I thought would be fun to try on the Mega PC, but I couldn't find a cable for it... another Idea was to try to upgrade the PC. I had heared of the Mega PC plus with a 486 and figured out the board was also used in the Amstrad PC7486SLC. I managed to find one that I was given for free!
I got to a point where I had the board out of the 7486 and had ideas to making a cable to the Mega CD.. but never finished as I met a Danish girl and moved to Denmark.. that and alot of other projects got put on ice all left in my Mums loft in UK...
Soon after my son was born around 2006 I decided to sell off alot of my collection (pressure from Mum too), some really nice stuff (mint boxed Wondermega and Mega Jet to name a few... aaaarghhh!). I couldn't get rid of my Amigas, they were my main passion... and the Mega PC had captured my cousins attention who was 13 at the time and just recently discovered all things retro... I gave him it along with a boxed ZX81, Atari 1040STE and some other stuff... I said if he ever didn't want them anymore to give them back, don't sell them! I don't remember what happened to the 486SLC board...
I had pretty much forgotten about them...
Last month my aunt sends me a photo saying "look what we have found in our loft". Amongst it all is the Mega PC.. the monitor has gone sadly, but the PC, controllers, keyboard etc looks in really nice condition apart from slight yellowing. I've asked her to look around for the monitor... and a 'circuit board in a black plastic bag' (the 7486slc board in antistatic).
I also need to get someone technical to open it and take out the battery!
I plan to go over to UK in October all being well and pick it up..
So doing a little searching online I have now found out there seems to be a little following of folks for this fascinsting machine 😀
After reading this thread i'm curious about some things...
How to do the audio quality improvement mod?
If my 7486slc board can't be found, i'd like to try to upgrade the original 386sx board processor, GFX etc.. so..
Are there any differences between the original 386sx board and 486slc apart from the additional circuitry for the 486?
Does it seem possible to add the circuirty for Flush, A20M, KEN, BIOS L1 etc to the original 386 board?
Does the 386 board have the same 5420 GFX chip?
If so, could the 5429 GFX chip be added instead of the 5428? It seems like an even more enhanced GFX chip with support for higher memory clock and memory mapped I/O...
I have seen a ti486sxlc2 66mhz CPU was once made.. I can't find any for sale, but have come across the 50Mhz G version on ebay. It seems its a 3.3v powered part with 5v I/O tolerance... some have reported it works Ok in 386sx machines at 5V power so i'm thinking of giving it a try.. have any of you guys had experience with it?
Hi Keropi, its me phipsy from Amibay 😀 What is this "special card" you are making ? Seems like a soundcard and scan doubler of some kind... care to share more details?