Amstrad Mega PC / Amstrad Mega PC Plus

Geez! It has been two years... so much has happened, yet so little
Welcome to the Mega PC club!

 

Thank you!
It arrived today so I'm pretty chuffed! Was supposed to be fully working and in great condition, but I had to replace the floppy drive and re-solder their cack-handed battery replacement. Speaking of which an LR2032 (that's the rechargeable version right?) is that likely to be fine just soldered in place of the old nickel cadmium battery?

 

Well good that you have it, annoying that it's bodgy! At least it can be fixed though
The LR2032 does look to be rechargeable and the same voltage.
The original battery is 60mAh, so as long as it is at least that you'll have an on-par back up battery!
Bigger the mAh, the longer the settings will stick when unplugged!
Any photos?

 

LR2032 is lithum and shouldnt be charged with a nicd charging circuit.

 

That's what I thought, already taken it out. I'll post up some pictures later on, the Pc side all seems to be working nicely, no issues there, standard 40mb hard drive 3320k extended Ram, no coprocessor and windows 3.1. Not been able to properly test the megadrive side myself but I've seen it working.
Would a the GBS-8220 definitely work as a substitute for a compatible monitor? (obviously with a monitor, I don't think I'd get very far just gawping at a circuit board)

 

reading this thread makes me want to get a megapc now

 

That's what it did to me!

Aaand here are some pictures



Here's a fairly standard board shot



Hard drive


Another standard board shot



Now here's where it gets weird

On the megadrive board (I know this is a terrible picture but it was a quick snap)
There's a cut trace and then a wire which was going to a point on the board, until it became detached while I was removing the card from the PC

Why would anybody do this?


and finally
there's this mess

 

Ok!

So I fixed the mess in the controller ports and they are now bolted down and soldered using wires with at least some competency.
I replaced the lr2032 with a couple of NI-MH AA batteries in a holder for the time being and thinking about doing the diode + cr2032

going to order a GBS8200 when I get paid this week and am eyeing up a (ridiculously pricey) co-processor


Quick questions,
1. Where would be the best palce to source more ram from and am I looking for anything special or is it just plain ol' 4mb 30pin FPM RAM ?

2.Would this work in my megapc?
http://www.ebay.co.uk/itm/370922226...WAX:IT&_trksid=p3984.m1423.l2649#ht_331wt_958

 

Regarding the 386 FPU, it's pretty much useless unless you want to run some ancient pc CAD software or something... assuming the socket on the 4th pic is the FPU one then the one you listed will fit.
If you insist on one personally I would get an intel 387sx rather than a cyrix one for this machine, but it's better to spend money on RAM or a bigger HDD rather than a useless FPU

 

Useless? That's my favorite type of expensive computer component
I am just researching at the moment, not definitely decided what I am doing with it, RAM would be a definite next step if I could find any, 4MB 30 pin FPM Ram sticks seem to be like gold dust! I had 4 compatible RAM sticks in a box, put it all in and it's identical in value to the original!

Edit: Guess I wasn't typing the right thing, I've now found a few on ebay

 

It's been 3 weeks and a fair bit has happened! (though it doesn't sound like much when I read it back haha)
I now have 16mb of RAM, a 6gb hard drive (using a drive overlay of course), a cyrix 387sx 25mhz coprocessor (I went for cyrix over intel because in the unlilkely event that i manage to get one of those clip-on cpu upgrades, the intel fpu chips are apparently not very compatible with them) and a sound blaster 16 card because I didn't really see the point in a network card for Dos/windows 3.1 (though I do have one in my box of computer bits should I happen to change my mind).
I *think* I have updated the video ram. If sim city 2000 runs in 600x476 and all the colours look as they should, does this mean that my upgrade has been successful?

Oh yeah, I bought a knock off Chinese GBS-8220, the picture has a bunch of interference and doesn't work in PC mode (well at least not in DOS anyway) but, I now know that the meagdrive side definitely works nicely. (The interference problem may be, at least partly as a result of the fact that I currently only have a 1A power supply to hand to test it with and all the literature demands 2A)

I also tried to install os/2, which, as it turns out, does not play well with drive overlay software. Windows 95 was tolerable but a bit too slow for my liking (when I installed the co-processor it seemed to give it a bit more kick though)

I tried a CF card+adapter but the system refused to boot from it and I didn't care enough to work out why not so I used it to back up all the files from the original hard disc so I can have a look at them later.

I think that's everything new, not sure anybody cares but hell, I've been enjoying myself!

 

^ awesome!!!! congrats on the setup! couple it with a megadrive Everdrive and you are set!

 

Hi all, I have registered to discuss my MegaPC.

I bought it a few months ago and have been on and off it as a side project.

It is a standard 386sx, came with 1MB RAM and a 40MB HDD (though it didn't have counterpoint installed).

It works nicely with my LG monitor, which has TV capabilities (it has RF and SCART inputs which makes it a great monitor for retrogaming), set to DTV mode it can handle both PC and MegaDrive VGA input!

My modifications so far:
- Replaced the battery, soldered in a barrel battery on a short length of wire.
- Upgraded the RAM. Ordered 16MB but unfortunately only 8MB of it worked. Still better than the 1MB!
- Added an SD card slot which replaces the IDE HDD (which sounded like it was on it's last legs!).
Unfortunately one of the original IDE socket pins snapped off, however using a cut needle I was able to install a pin into the cable connection. The other end goes to a small board which is mounted on a plate which sits on the ISA end. It does block me from installing an ISA board there, however it does give me easy access to the SD card.

Currently I use a 128MB SD card, which I can swap between the MegaPC and my main PC (obviously when the MegaPC is off!)

I've installed DOS 6.22, Win 3.11, Clarisworks and a few games. Tried briefly to install Office 4.3 but ran out of space.

I'll add pictures if anyone is interested.

I have a few questions:
- How straightforward is it to add more VRAM? Do the chips push in to the socket, or is a lot of soldering required?
- What is the max HDD size supported? I've seem 504MB and 540MB bandied about. If the latter, I'd probably use a 512MB SD card.
- Upgrading the 386 processor, is a 486SLC a matter of taking the 386 chip out and dropping in and getting the cache software?

It came with original Amstrad Megadrive gamepads, however the buttons need a good bash to register input, I might seek "newer" Sega gamepads and switch the internals.

I'm on the lookout for a decent 1990s clicky style UK layout PS/2 keyboard, which are strangely hard to find (every 90s PC had one, great era for keyboards, wish I had kept a few!)

Might invest in an Everdrive, I have a lot of ROMs on SD for my handheld Firecore.

It's nice to play 386 era software, the old Apogee platformers, MS Entertainment Pack, Alex Higgins Snooker (by Amstrad!), Dizzy etc.
Not overly concerned with running 486/Pentium era games on it, I have a Toshiba T2130 (no soundcard) and Libretto 50CT for that. (And a Thinkpad 380Z Pentium 2)

Thanks all!

 

@Hedgeyourbets - Nice a genuine Intel 386, mine had the old Am386
@sirwiggum - Absolutely we'd love some photos - more the merrier! To try and answer your questions...

VRAM - Just push into the empty slots (unless already populated of course), I'm not sure what the maximum VRAM was on the 386 board, might have been 512kB total and the 486 model is 1MB max... someone else will need to chime in and confirm that though! Here's what I ended up putting in my 386 here.

Hard Drive - I only ever tried the drive I had in there (around 300MB from memory), the 486 has a lot more flexibility when using other drives - it actually has autodetect... big feature! I'd be curious as to what the largest hard drive others have put in and had recognised though! I did use hard drive overlay software to bump the size up on the 486 at some point, don't see why that wouldn't work on the 386 version. Quantum Dynamic Drive Overlay 9.52 which was made by ONTRACK.

386 -> 486 - You can get clip on CPUs that are pretty whizbang cool - others have taken that path and it seems to be a good bet (hard to come by though). The 486SLC version is actually a complete motherboard replacement. Here's the 386 board and the 486 board. Quite different layouts but electrically and physically compatible! Motherboard model is PC7486SLC / WB486SLC for the 486 version.

Backup Battery - If it's still on there remove it! Hopefully it hasn't leaked damaging the motherboard. You might see in my photos of the 386 album that there was a 50MHz 486... but it might have sort of... errr had some blue sparks flying about So don't do that!

More photos of both in the galleries below:-
386SX Gallery
486SLC Gallery

And if anyone watching finds the above links are busted, feel free to head to my website in my signature and click on the photos section which will take you off to Google Picasa or Google Plus. Then just search for Amstrad and it will pop-up pretty quick!

And limboy777, if you are watching I received the XT-CF-Lite v4.1 Card PCBs. I'll have to wait until holidays in late September but I will get around to doing what I said I'd do! (Which I've coincidentally forgotten, but have written down somewhere!)

 

Thanks @RetroJunkie !

Here are some photos of what I've got so far:

Original battery

IMG_20150207_133129[1] by sirwiggum posted Aug 12, 2015 at 1:32 PM

Replaced battery with a Varta NiMh, as the legs were different I used a short length of wire. Probably not the most elegant, but it did the job.

IMG_20150208_143611[1] by sirwiggum posted Aug 12, 2015 at 1:33 PM

Bank of RAM, 2x 4MB now

IMG_20150208_143627[1] by sirwiggum posted Aug 12, 2015 at 1:33 PM

The broken IDE pin, resolved by sticking a cut needle into the ribbon cable

IMG_20150208_143724[1] by sirwiggum posted Aug 12, 2015 at 1:33 PM

The Megadrive board

IMG_20150207_133629[1] by sirwiggum posted Aug 12, 2015 at 1:33 PM

Exterior - underside - no foot here, but it rests on the PS/2 cables so it doesn't tend to wobble

IMG_20150207_131534[1] by sirwiggum posted Aug 12, 2015 at 1:32 PM

The IDE SD card slot at the rear

IMG_20150322_130738[1] by sirwiggum posted Aug 12, 2015 at 1:32 PM

Exterior, works well with the LG monitor

IMG_20150207_131050[1] by sirwiggum posted Aug 12, 2015 at 1:32 PM

IMG_20150207_131039[1] by sirwiggum posted Aug 12, 2015 at 1:32 PM

Running Windows 3.11 - I initially turned virtual memory off as I didn't want thrashing on the SD card, however ClarisWorks needed Win32s installed which needed virtual memory, so I turned it back on.

IMG_20150322_142410[1] by sirwiggum posted Aug 12, 2015 at 1:32 PM

And running Sonic!

IMG_20150322_130710[1] by sirwiggum posted Aug 12, 2015 at 1:32 PM

 

Wow! You sure lucked out with the non-leaking battery
Very nice looking machine, thanks for the photos!

 

Thank you!

I changed the battery first thing, it seemed to have been sitting dead anyway. Damage seemed to be that weak IDE pin.

It is a bit yellowed (as 80s/90s beige tech seems to be) and I wouldn't want to retrobrite it in case I lose the Amstrad logos.

The SD card is my favourite feature, putting software on it (and, indeed, getting files off it - you could use it as a word processor and print / email / blog etc. from a modern PC), the bios was a bit fiddly getting the right HDD settings. I will try a 512MB card and see how I get on.

 

Yep! That does seem to be the best way to do it. I've gone down the CF card route because I bought a reader a while back and enjoy using it... Hahaha, well not really but time will tell. SD cards are great though, especially if you can use sizes that are available these days for a dollar or two. What's the smallest size these days? 4GB? I remember having issues like that for something else I was working on... how fast technology moves

Retr0bright does seem to be a fair bit of hassle for minimum reward! Well unless what you are retr0brighting is sitting in your lounge room as a feature!

Failing the 512MB SD card, feel free to give overlay software a try! Quite a good way to gain a lot of space - if you even need it! Minesweeper isn't that big after all ;D

 

Hi all,

Just signed up as this seems to be the place to talk about the Mega PC

I've just repaired a couple of these machines that had been left for a long time and who's batteries had leaked. I removed the batteries of both machines but ended up having to replace the IDE connectors and clean the boards. Neither would see their drives at this point, and as I could not locate a schematic of the motherboard I ended up having to do some track tracing with the aid of the datasheets for the WD chipset. Several wire patches later and both machines would then see floppies and hard disks.

Unfortunately both of the original Seagate drives where faulty and I have had to replace them with a pair of old IBM drives, but having done this I was able to install Dos from floppy.

At this point I had two machines one of which had 1Mb and the other with 4Mb, again looking at the chipset datasheet I saw that it supported 8 simms even though there where only 4 sockets (and a place for 4 more), so I cleaned out the holes and fitted extra sockets and now have two machines with 8 sockets (20Mb in one machine and 8Mb in the other).

What I don't have however is the original drivers and software that came with the machines, does anyone have this or know where I could get it, it would be good to be able to use the machine to it's fullest. If anyone had the technical reference document that would be cool too.

Cheers.

Phill.

 

Just for anyone else visiting this thread in the future - I've popped all the files I have for the Amstrad Mega PC up on Google Drive here. Please enjoy responsibly