Amstrad Mega PC / Amstrad Mega PC Plus

[RetroJunkie]

RetroJunkie - thats only the Dreamcast thread, there is a Saturn one too.

Out of control is what you are good sir!

Dropped off my monitor and one the mega pc's (the one i took the battery out of) to a retired tv repair guy a few days ago. He was really old but confident...

His diagnosis on the monitor switch that wont stay in was that he will try to repair. Worst case is that he will make it so its always on (fine with me as the monitor is powered by the mega pc).

I have opted for a NIMH replacement on this one as ive seen a few people say that the motherboard expect this type of battery and using something else may cause an explosion!.

Got my ISA network card. Wont install it at the moment as no time and trying to get my new seagate 540mb hdd to load dos

http://s1269.photobucket.com/albums/.../Netowrk Card/

One of my problems is getting the cyrix cache software from the old hdd onto the new one. I got a lot of help from another chap on another forum. This is how the cache shows in autoexec.bat and in windows file manager:

http://s1269.photobucket.com/albums/... PC/486 Cache/

Im worried i may have damaged one of the tracks on one of the mega pc's (i took another battery of). Hoping our resident expert solderer (if thats a word) and resident mega pc motherboard repair guy can help - I scraped a bit of the motherboard near the negative battery connection:

Also c7 and c8 on the motherboard look corroded, there was some white stuff that I removed ....:

http://s1269.photobucket.com/albums/jj587/limboy777/Amstrad Mega PC/Damaged tracks/

I ended up jamming my monitor switch in, haven't turned it off since as I know it will not go back in if I do!

Oh I saw the Amibay posts - too bad that disk image the fellow uploaded has a captcha that doesn't seem to load! Would be interesting to compare what his diskette had compared with your own! Doing what keropi said on the forums over there will allow you to snap up that cache software though. If you do feel up to it be sure to make a disk image using WinImage so the past may be preserved. For King and Cachery!

As for the battery negative terminal... Are you crazy? That looks fine! :-) Just use a multimeter to check for continuity if you are worried. Also from what I remember you can just use the other negative terminal below the damaged looking one. I miss my Mega PC. I need to get home to it!

Where's C7 and C8? I can't see them there on those pictures?

[limboy777]

Out of control is what you are good sir!



I ended up jamming my monitor switch in, haven't turned it off since as I know it will not go back in if I do!

Oh I saw the Amibay posts - too bad that disk image the fellow uploaded has a captcha that doesn't seem to load! Would be interesting to compare what his diskette had compared with your own! Doing what keropi said on the forums over there will allow you to snap up that cache software though. If you do feel up to it be sure to make a disk image using WinImage so the past may be preserved. For King and Cachery!

As for the battery negative terminal... Are you crazy? That looks fine! :-) Just use a multimeter to check for continuity if you are worried. Also from what I remember you can just use the other negative terminal below the damaged looking one. I miss my Mega PC. I need to get home to it!

Where's C7 and C8? I can't see them there on those pictures?

Yes Ive sent the other chap another message to see if I can get the software of him. If I get the software working, Ill put up the image for other users. Im thinking of taking off the 486 chip as it clip on just to have a look underneath but worried I may damage something (im really cautious...)

It didnt look bad but was worried just in case!. I dont have the time and space to take it all apart and desolder so just chopped it from the top! The C7 and C8 are in the second picture in that album (just next to the postive battery part of the motherboard).

You need to get back to the Mega PC, Im waiting for your update on the vga chips. On one of the PC's Ive got full 512k RAM so might just swap over the chip however I dont know if I need a tool to get it off? I dont want to use a screwdriver or pin just in case I crush the plastic...

Im also looking for an ISA video card, the best that I can get (I believe 2mb RAM on board some of them! more than double the system RAM on the stock mega PC). Just needed someone like Bad Ads earlier post to confirm that it should be OK!

Also waiting for my 16mb RAM coming from USA...

Does the Quantum Drive Overlay work with any drive or is it drive specific?

[Bad_Ad84]

Negative is fine, but there is a trace next to it I would test.

Fortunately, you can see 2 vias (1 at each end) that you can probe with a multimeter to confirm its connected ok.

C8 and C7 are probably OK, but you can (assuming you have the skills) remove them, put new solder onto the pads (and remove again to clean up the pads) then fit new caps. Will be good as new then.

Points to probe:

[RetroJunkie]

Yes Ive sent the other chap another message to see if I can get the software of him. If I get the software working, Ill put up the image for other users. Im thinking of taking off the 486 chip as it clip on just to have a look underneath but worried I may damage something (im really cautious...)


It didnt look bad but was worried just in case!. I dont have the time and space to take it all apart and desolder so just chopped it from the top! The C7 and C8 are in the second picture in that album (just next to the postive battery part of the motherboard).


You need to get back to the Mega PC, Im waiting for your update on the vga chips. On one of the PC's Ive got full 512k RAM so might just swap over the chip however I dont know if I need a tool to get it off? I dont want to use a screwdriver or pin just in case I crush the plastic...


Im also looking for an ISA video card, the best that I can get (I believe 2mb RAM on board some of them! more than double the system RAM on the stock mega PC). Just needed someone like Bad Ads earlier post to confirm that it should be OK!


Also waiting for my 16mb RAM coming from USA...


Does the Quantum Drive Overlay work with any drive or is it drive specific?

I was able to get the Quantum branded overlay to work with a Seagate and the Disk On Module too from memory. Thankfully it didn't seem to have as many limitations on it as when I tried to use it on my Athlon 500MHz. That said no-no-no not loading on here. The Kroll Ontrack overlay works a charm though, you'd be crazy not to use it :-)


Oh I see the capacitors in that photo above now! I must have been looking at one that didn't show them! My bad!


I really do need to get back to the Mega PC to check that VRAM - Geez that was meant to be checked ages ago... Sorry about the delays!

C8 and C7 are probably OK, but you can (assuming you have the skills) remove them, put new solder onto the pads (and remove again to clean up the pads) then fit new caps. Will be good as new then.

Out of curiosity, how does one tell what the value of that caps are when they have no markings on them?

[Bad_Ad84]

Check with a meter that measures capacitance :)

[RetroJunkie]

Check with a meter that measures capacitance :)

Pffft who has time for that! What if the caps are bad though... ? Best just to leave them be?

[Bad_Ad84]

If the caps are bad, they should be replaced.

Need to find a schematic or someone with the same device to check the values.

[RetroJunkie]

If the caps are bad, they should be replaced.

Need to find a schematic or someone with the same device to check the values.

Ouch! Lucky Limboy777 has eight Mega PCs :-) Hope he has some tweezers too to lift that cap off the board!

[limboy777]

Negative is fine, but there is a trace next to it I would test.

Fortunately, you can see 2 vias (1 at each end) that you can probe with a multimeter to confirm its connected ok.

C8 and C7 are probably OK, but you can (assuming you have the skills) remove them, put new solder onto the pads (and remove again to clean up the pads) then fit new caps. Will be good as new then.

Points to probe:

I have no soldering skills but got one in the post today! Looked at some youtube vids and will be practicing on broken (or soon to be broken) electric stuff. Never used a multimeter though....

Are the things on C7 and C8 caps?

[limboy777]

Is the Knoll On track available on line?

I also emailed the seller re the 486 SLC advert. He scanned it from a friends magazine a long time ago. Have asked if he check if he can get the magzine

If not I will scan you the scan copy and post it up.

[limboy777]

Ouch! Lucky Limboy777 has eight Mega PCs :-) Hope he has some tweezers too to lift that cap off the board!

Does the service manual I provided a link to have these details?

I havent the tools the check the capacitance values? If you let me know what I need to do, Ill try and help but remember Im a newb!

Got my monitor and one of the mega pc's back. Hes not done a good job to be honest. I think hes too old. For the battery replacement, he dropped solder on 3 places and didnt solder the battery properly (in fact it still had the battery error/cmos error). I looked at it closely and nudged it and one of the connections he made came of quite easily so ££ wasted there! I didnt take pics as I was pissed off at the time...Thankfully the dropped solder just came of with a slight nudge from a screwdriver.

The monitor...he drilled a hole and used a piece of plastic to push down the switch....It works but I was expecting something more professional which I wouldnt be able to see..

Not going to go back to him as he's probably going to break something. I have got my solder but I need to practice or I might put a services wanted ad on Amibay for someone local and professional to do it. Im waiting for another mega pc owner to send me some pics of his cr2032 mod as I think this is the way to go. (Bad Ads - are you ever around in the Lancashire area? - I go to Leeds, Manchester and Newcastle on work as well?)

Good news is that I got my 16mb ram posted and installed 8mb of it on my 8mb machine and it all works (I didnt want to remove the ram that was already there as I had my "if it broke dont fix it" hat on. The seller listed the ram as used but they came in sealed packs and were new so very happy..."

http://s1269.photobucket.com/albums/jj587/limboy777/Amstrad Mega PC/16mb RAM/

(Retro if you need the link to where I bought from for the 386, let me know, he has two sets left and they are the cheapest! (plus they are new and work with the mega pc!)

so my main mega pc now has the 486 chip and 16mb RAM, just need an ISA graphics card with 2mb RAM ( I think this is the highest at the time?) and get a hard drive to work with the damn thing. Retro you mentioned you had some problems with getting lots of hard drives to work, what were the steps you took to get the DOM working? I think I may go down this route with the drive overlay....(this weekend is my last try on the 540mb HDD)

Got some megadrive carts (got about 30 in total) . Part of the collection included one Japanese megadrive game (fantasia) and one genesis (U.S) game (WWF wrestmania or something). I tested both of these and they worked fine so the Mega PC works with all region carts. Retro's probably already stated this somewhere but I couldnt remember so just tested it anyway.

I looked through the pc7386 manual and there is some info on changing the jumper settings to use an ISA video card. Will post this up for you Mr Junkie. I havent tested the ethernet card as I dont really see the point of using internet on these machines, making them into DOS gaming machines is the way to go.

Re 8 Mega PC's. Ive only got 3! (cant remember if I mentioned my latest aquisition on here or somewhere else) - I see them as an investment as well as a hobby (plus they are awesome machines). If you use the princliples of stocks and shares and look at patterns, the Mega PC will only go up in value like the Terradrive especially as so many are dying because of leaking batteries and because people are buying up DOS gaming rigs (i.e 386 /486 pcs) for more than megadrives. The market is at the troughs, just wait for it to hit a peak!

[Bad_Ad84]

I am around the Birmingham upto Nottingham areas. You are probably a bit too north for me

[Nemesis]

Out of curiosity, does anyone here who owns a MegaPC want to trade disk images or manual scans? I have perfect disk images of Counterpoint, the 3 MSDOS 5 install disks, several games and game collections that came with the system when I purchased it, and the first of the two driver disks, but I seem to have misplaced my second driver disk. I'm also short on MegaPC documentation. Does anyone here have software or manuals, and want to trade scans/disk images?

[RetroJunkie]

Out of curiosity, does anyone here who owns a MegaPC want to trade disk images or manual scans? I have perfect disk images of Counterpoint, the 3 MSDOS 5 install disks, several games and game collections that came with the system when I purchased it, and the first of the two driver disks, but I seem to have misplaced my second driver disk. I'm also short on MegaPC documentation. Does anyone here have software or manuals, and want to trade scans/disk images?

I wish I did! Boy do I wish I did. And to make it worse my original Mega PC hard drive looks like it broke a long time ago and they stuck some junk Seagate drive in there. Boo!

[Nemesis]

I wish I did! Boy do I wish I did. And to make it worse my original Mega PC hard drive looks like it broke a long time ago and they stuck some junk Seagate drive in there. Boo!

Here you go:
http://www.ebay.com.au/itm/380415221990

That's the exact model of drive the Amstrad MegaPC shipped with, the Seagate ST351A/X. You'll find them on ebay fairly often, they weren't that rare. Occasionally they come on for cheap, but that one's not too bad. You'll find some people trying to flog them for a lot more. They're actually quite a useful drive, fairly sought after. I forget why. That's not the Seagate drive you have is it, because if so, it's the right one. :)

[RetroJunkie]

Here you go:
http://www.ebay.com.au/itm/380415221990

That's the exact model of drive the Amstrad MegaPC shipped with. You'll find them on ebay fairly often, they weren't that rare. Occasionally they come on for cheap, but that one's not too bad. You'll find some people trying to flog them for a lot more. They're actually quite a useful drive, fairly sought after. I forget why.

Ahhhh now I know what it was supposed to have. It had a Seagate to begin with? Mine had this fella in it and the HD Type label removed off the back of the machine. My disk on module is a beast! Wouldn't have it any other way So quiet!

Oh while I've got your attention here are some photos I just upped of the Model 3 TeraDrive I picked up. The yellow trace wires are different between my Model 2 and Model 3.

[Nemesis]

Hey, they are slightly different aren't they? Well my early model TeraDrive with S/N 100000201 is actually missing most of those traces, it only has the single yellow wire connecting to the WD76C30 chip. That makes sense seeing as I now know it was used internally within Sega. Most likely it was an early test/demo unit. The MB S/N for that unit is 000421. My later model system has the same traces as your model 2 system. It has a S/N of 100006218 (hey, almost the same as yours, they're cousins ), but the MB S/N is 001033, so the board was actually assembled a lot earlier. Your model 3 system with S/N 100006271 has a M/B S/N of 0007279, so your board is a much later revision. Looks like they tweaked the modifications ever so slightly. What's the MB S/N for your model 2 system? It might help narrow down when the board modifications changed.

As a note, has anyone ever seen a TeraDrive with a S/N higher than 6218? I've seen a number of these systems over the years, but I don't think I've ever seen one higher than that. It looks like this system definitely sold less than 10,000 units, perhaps no more than 8,000.

[limboy777]

Out of curiosity, does anyone here who owns a MegaPC want to trade disk images or manual scans? I have perfect disk images of Counterpoint, the 3 MSDOS 5 install disks, several games and game collections that came with the system when I purchased it, and the first of the two driver disks, but I seem to have misplaced my second driver disk. I'm also short on MegaPC documentation. Does anyone here have software or manuals, and want to trade scans/disk images?

Hi mate

Happy to give you (or anyone else the info/images). Ive got some of the missing items you need.

I have the two driver disks
All the manuals including rare stuff such as the one page quick setup guide etc.

TBH scanning the bigger manuals would be a pain in the rear so Ive never thought of doing it -one of them is exactly the same as the one supplied with the PC7386 (in fact thats the title of it of the top of my head). The mega pc manual and counterpoint manual and some of the leaflets are pretty small so should be able to do this however it will be a while as I have an old scanner that only works with windows xp and i hate using my old xp laptop (the only time ive used it, is to download floppy images as it has a floppy drive).

Would love disk images of the MS DOS disks and games as they are the ones missing from mine. I would like scans of the disk labels so I can reproduce them to complete the collection and can do the same for you! Sending you a PM!

[limboy777]

I am around the Birmingham upto Nottingham areas. You are probably a bit too north for me

Thanks. I managed to find a chap at work that will do it for me athough hes not done it before. Im getting some diodes in the post so hopefully this time it will be OK.

[limboy777]

Ahhhh now I know what it was supposed to have. It had a Seagate to begin with? Mine had this fella in it and the HD Type label removed off the back of the machine. My disk on module is a beast! Wouldn't have it any other way So quiet!

Oh while I've got your attention here are some photos I just upped of the Model 3 TeraDrive I picked up. The yellow trace wires are different between my Model 2 and Model 3.

Ive ordered a y molex connector and have a spare 3 way ide cable. Im thinking of putting in a 80gb hd AND a 2gb DOM/CF solution. The CF/DOM to load windows and use the 80gb as secondary. I just need the HDD working first....

Also researching floppy emulators and potentially zip drives!

One of my mega pc's has some damage to the front casing/fascia and it will give me an opportunity to experiment hahah hahaha (evil laugh). Im waiting for some spares to arrive....