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Amstrad Mega PC

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Reply 201 of 214, by smsdave

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I’ve been playing with my Mega Card a lot the last few weeks and wanted to share a few experiences and ask a couple of questions here publicly in case the answers/discussion helps out others.

First off, this thing is AMAAAZING. I’m no audiophile but I nearly wept when I first heard how rich and full the intro sequence to Dune 2 sounded with the X3GS and everything turned on!

Soldering the miniscule resistor for the optional 60Hz mod (after many years away from a soldering iron) was nothing short of terrifying but I managed it without issue and was glad I had; the speed improvement over 50Hz megadrive gaming is massive. I like the ability to switch between 50/60 but doubt I’ll use it much as 60Hz is the only way for me now. I found soldering the clock signal wires trivial and nothing for even the clumsiest person to fear (for those who don't want to take any risk and are happy with their megadrive speed). Watching the RMC review video (https://youtu.be/nOyza3cOOqM) was really helpful to double check what I was doing every step of the way.

Using networking from DOS for the first time was easy enough once I figured out that I could get the software interrupt number I needed to configure the mTCP tools from running the packet driver (PNPPD.COM, downloaded from the link on http://mega-pc.eu). Once I’d added ‘PACKETINT 0x60’ to the mTCP config file, running DHCP.EXE was all that was required to finish configuring mTCP and I was happily using the rest of the suite. Using FTPSRV is a lovely way to quickly remotely manage large numbers of files on the MegaPC from my modern machine. I needed to put my FTP client into single connection mode so it doesn’t overload the server with multiple connections when sending. I haven’t yet tried getting networking in Win 3.11 but networking in Windows 95 worked out of the box with zero config IIRC.

The scanline doubler works exactly as advertised to allow much higher grade monitors to support the Megadrive side and looks gorgeous as per keropi’s photos; my Amstrad monitor will now be going into the loft I suspect.

A few questions I had:

1) I found myself having to disable LPT in the BIOS to free up IRQ7, and then edit ALS.INI to set SB16IRQ=7 to get the soundblaster card working. This was seemingly the same way as Neil on the RMC video, is this the ‘right’ way to do things?
2) I’m experimenting with what’s the best DOS/Windows/partition setup for my CF card to make use of the XT-IDE BIOS and would be interested in recommendations?
I’m no DOS expert and I’m primarily using the PC side for DOS games but like to be able to run Windows for some nostalgia. I was previously on a ~500MB FAT16 partition with MS-DOS 6.22 and Win3.11. To make use of the larger partition support I tried MS-DOS 7.1 CDU (https://winworldpc.com/product/ms-dos/7x) and was happily using a 16GB FAT32 partition but then realised Win3.11 doesn’t play nicely with FAT32 (though I note there are hacks out there that may help).
Consequently I did a clean install of Win95 OSR 2.5 on an empty partition and edited MSDOS.SYS setting BOOTGUI=0 so it boots to MS-DOS 7.1 prompt which seems like a reasonable compromise but have struggled to get enough conventional memory free to run games like Dune 2 in that setup as I think Windows is still pre-loading too much. At least Windows95 works much better than I had ever thought it would (with 16MB RAM and 512KB VRAM).
3) Out of curiosity, would the X3GS daughterboard sold with the Mega card work with the Orpheus I card as well?

It’s a truly incredible piece of kit and I have loved every minute of playing with it to make the MegaPC into something very special. Thank you keropi, we're honoured to have the benefit of your impressive skills!

Reply 202 of 214, by keropi

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smsdave wrote on 2022-01-19, 23:19:

I’ve been playing with my Mega Card a lot the last few weeks and wanted to share a few experiences and ask a couple of questions here publicly in case the answers/discussion helps out others.

First off, this thing is AMAAAZING. I’m no audiophile but I nearly wept when I first heard how rich and full the intro sequence to Dune 2 sounded with the X3GS and everything turned on!

Thanks for the kind words!!! I am very glad you are enjoying the MegaCard 😁

smsdave wrote on 2022-01-19, 23:19:

Soldering the miniscule resistor for the optional 60Hz mod (after many years away from a soldering iron) was nothing short of terrifying but I managed it without issue and was glad I had; the speed improvement over 50Hz megadrive gaming is massive. I like the ability to switch between 50/60 but doubt I’ll use it much as 60Hz is the only way for me now. I found soldering the clock signal wires trivial and nothing for even the clumsiest person to fear (for those who don't want to take any risk and are happy with their megadrive speed). Watching the RMC review video (https://youtu.be/nOyza3cOOqM) was really helpful to double check what I was doing every step of the way.

I fully agree the RMC video is truly awesome and the fact that he showed installation is really way better than any instructions I could write!

smsdave wrote on 2022-01-19, 23:19:

Using networking from DOS for the first time was easy enough once I figured out that I could get the software interrupt number I needed to configure the mTCP tools from running the packet driver (PNPPD.COM, downloaded from the link on http://mega-pc.eu). Once I’d added ‘PACKETINT 0x60’ to the mTCP config file, running DHCP.EXE was all that was required to finish configuring mTCP and I was happily using the rest of the suite. Using FTPSRV is a lovely way to quickly remotely manage large numbers of files on the MegaPC from my modern machine. I needed to put my FTP client into single connection mode so it doesn’t overload the server with multiple connections when sending. I haven’t yet tried getting networking in Win 3.11 but networking in Windows 95 worked out of the box with zero config IIRC.

ah you are doing it the "keropi Approved"©® way , nice! 🤣 🤣 🤣
yeah mTCP's FTPServer is the best way to do file transfers to any DOS system IMHO

smsdave wrote on 2022-01-19, 23:19:

The scanline doubler works exactly as advertised to allow much higher grade monitors to support the Megadrive side and looks gorgeous as per keropi’s photos; my Amstrad monitor will now be going into the loft I suspect.

Same here - monitors in storage!
Tiido did an awesome work on the specialized scandoubler for the MegaPC , it could not have turned out better!

smsdave wrote on 2022-01-19, 23:19:

A few questions I had:

1) I found myself having to disable LPT in the BIOS to free up IRQ7, and then edit ALS.INI to set SB16IRQ=7 to get the soundblaster card working. This was seemingly the same way as Neil on the RMC video, is this the ‘right’ way to do things?

Yep, disabling LPT in BIOS is needed if you want to use IRQ7 - I must put this note on the website too thanks for the reminder
You could have avoided the manual editing of ALS.INI and run ALCONFIG to adjust the resources, it will edit the INI file automatically and adjust any windows 3.x INI files as well

smsdave wrote on 2022-01-19, 23:19:

2) I’m experimenting with what’s the best DOS/Windows/partition setup for my CF card to make use of the XT-IDE BIOS and would be interested in recommendations?
I’m no DOS expert and I’m primarily using the PC side for DOS games but like to be able to run Windows for some nostalgia. I was previously on a ~500MB FAT16 partition with MS-DOS 6.22 and Win3.11. To make use of the larger partition support I tried MS-DOS 7.1 CDU (https://winworldpc.com/product/ms-dos/7x) and was happily using a 16GB FAT32 partition but then realised Win3.11 doesn’t play nicely with FAT32 (though I note there are hacks out there that may help).

You have 2 options:
- use a FAT16 DOS and make a bunch of 2GB partitions in your large CF
- use a FAT32 DOS , have a single partition and patch win3.11 so it does not behave weird when exiting them

I am using the 2nd option with a 32GB CF and a 7.1/3.11 setup. I have not tried win95 at all on a MegaPC - isn't it a somewhat painful experience? 🤣
Just use the 2 patches that are posted in this thread I made almost a decade ago: Making Windows 3.11 work in DOS7.10 (patches inside) and you'll be good
But keep in mind you won't be able to have a permanent windows swap file or enable 32bit disk access - this seems to be because of of both XT-IDE and FAT32 filesystem
but I did not bother to investigate more tbh as things work fine as-is and the MegaPC is not a speed demon either...

smsdave wrote on 2022-01-19, 23:19:

Consequently I did a clean install of Win95 OSR 2.5 on an empty partition and edited MSDOS.SYS setting BOOTGUI=0 so it boots to MS-DOS 7.1 prompt which seems like a reasonable compromise but have struggled to get enough conventional memory free to run games like Dune 2 in that setup as I think Windows is still pre-loading too much. At least Windows95 works much better than I had ever thought it would (with 16MB RAM and 512KB VRAM).

You can always make a DOS multi-config menu and have items for XMS, EMS, Win95 etc
The instructions here are valid for 7.1 : http://smallvoid.com/article/dos-multiple-con … igurations.html
You can save a nice chunk of memory by using DRMOUSE from DR-DOS instead of Microsoft's MOUSE.COM - it only needs ~6kb and is as compatible as the microsoft driver.
It's my go-to mouse driver nowdays for systems like the MegaPC where there is no driver to create UMB blocks under an XMS-only configuration.

smsdave wrote on 2022-01-19, 23:19:

3) Out of curiosity, would the X3GS daughterboard sold with the Mega card work with the Orpheus I card as well?

Ofcourse, it is a normal wavetable daughterboard : it will work with any soundcard out there that has a waveblaster header and it will work via USB on a modern system

🎵 🎧 PCMIDI MPU , Orpheus Soundcard , Action Rewind and Megacard website

💻 WTB Amstrad PC7486SLC-33

Reply 203 of 214, by smsdave

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You're right that Win95 isn't a great everyday experience, it's more that I was expecting it to be even worse! 😀 I've got a Cyrix 486 clip-on CPU that I'm going to install once I've got everything stable which will be interesting to see if it improves Win95 a little but I suspect CPU frequency isn't the main bottleneck on the MegaPC.

Thanks for the tip on the DR DOS mouse driver and mutli-config menu, I'll definitely give those a go.

I definitely want to go with a FAT32 DOS and Win 3.11, I'm assuming you mean plain 3.11 and not Windows for Workgroups 3.11, unless there's a good reason to choose WfW e.g. for the network card?

I've tried out the W3XSTART.exe patch with MS DOS 7.1 CDU from winworldpc.com before attempting to install Win3.11 but the patch tool doesn't seem to like it. Running W3XSTART.exe after using a 7.1 floppy boot disk with the machine set up with C drive with CDU DOS 7.1 on, it reports C:\io.sys is valid but then after taking a few mins on the 'Searching code' phase reports "Error: Code to patch/unpatch could not be found". Is there a different source of MS-DOS 7.1 you'd recommend or should it work with that CDU release?

Reply 204 of 214, by keropi

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smsdave wrote on 2022-01-24, 21:15:

You're right that Win95 isn't a great everyday experience, it's more that I was expecting it to be even worse! 😀 I've got a Cyrix 486 clip-on CPU that I'm going to install once I've got everything stable which will be interesting to see if it improves Win95 a little but I suspect CPU frequency isn't the main bottleneck on the MegaPC.

those clip-on upgrades can be quite temperamental in my experience, their main issue is that they don't make good contact and this leads to instability....

smsdave wrote on 2022-01-24, 21:15:

I definitely want to go with a FAT32 DOS and Win 3.11, I'm assuming you mean plain 3.11 and not Windows for Workgroups 3.11, unless there's a good reason to choose WfW e.g. for the network card?

I actually never used the "plain" 3.11 version, I always install the WfW one... I do not think there is a difference if you don't install network drivers - and if you do then you will install the NDIS/3 ones from the site for the RTL8019 so it will be a native WfW driver without any DOS components.
I have not tried it with win10 (because of mTCP FTPserver there was no need tbh) but with win7 you would install the MS TCP/IP package and then a windows7 system could connect to a share on the 3.11 system. Transfers would work but they would be ~50% speed of what you get with mTCP.

smsdave wrote on 2022-01-24, 21:15:

I've tried out the W3XSTART.exe patch with MS DOS 7.1 CDU from winworldpc.com before attempting to install Win3.11 but the patch tool doesn't seem to like it. Running W3XSTART.exe after using a 7.1 floppy boot disk with the machine set up with C drive with CDU DOS 7.1 on, it reports C:\io.sys is valid but then after taking a few mins on the 'Searching code' phase reports "Error: Code to patch/unpatch could not be found". Is there a different source of MS-DOS 7.1 you'd recommend or should it work with that CDU release?

I have never used that 7.1 release... what I use is the DOS from 98SE - with this W3XSTART works fine. It seems from your error that the CDU release is not supported by the patcher...

🎵 🎧 PCMIDI MPU , Orpheus Soundcard , Action Rewind and Megacard website

💻 WTB Amstrad PC7486SLC-33

Reply 205 of 214, by judgereinhold

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Hi everyone, first time poster here but have been keeping up to date with this thread for a while. I'm currently trying to repair my Mega PC which had suffered damage from the leaking battery. I've repaired all of the traces and checked continuity etc and all seems ok but I'm now getting this error on boot up when I use a post card:

'8A Initialise extended BIOS data area'

The system is not yet outputting a video signal - I've tried with the original monitor and an LG panel that I know is dual sync (not that it matters for just testing the pc though obviously)

I've previously had a bit of help from Keropi by email (thanks very much!) but rather than just bothering him I thought I'd put my latest problem on here to see if anyone has any advice.

Currently there is no battery connected, so the CMOS should have been cleared. I'm planning to use an external battery pack on the external battery headers when it's up and running.

Does the Mega PC need to be fully assembled to output video? At the moment I've just been testing the 386 motherboard connected to the PSU and monitor.

Also to note there is an IC that lifted off the motherboard near to where the battery leaked which I haven't been able to replace as the pads came off too with the corrosion. However this is a chip that looks after one of the serial ports so I don't think would give me this current error.

Thank you!

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Reply 206 of 214, by AndrewK2685

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From what I know from mine, you need to connect the mega drive card to the motherboard connector
or jumper it to pass the video & audio signals.
as for post error, maybe stops because it detects no CMOS battery
try pressing F1 and see what happens (I think this is the "continue" button)
or del (Bios) - I dont remember exact keys for megapc though tbh

Reply 207 of 214, by keropi

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yep, install some jumpers like this:

EseR1iM.jpg

so the motherboard is "locked" to vga-only - then you can test with a psu and a normal VGA monitor

🎵 🎧 PCMIDI MPU , Orpheus Soundcard , Action Rewind and Megacard website

💻 WTB Amstrad PC7486SLC-33

Reply 208 of 214, by judgereinhold

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Thanks very much AndrewK2685 and keropi - you were both right. I've set the jumpers to force VGA output and can now see that the pc has successfully booted and has paused because there is no CMOS battery. So happy to have got this working again, will put it all back together and clean everything up (case etc) to check all working correctly and after that I'll install the mega card! Awesome - thanks again

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Reply 211 of 214, by judgereinhold

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Hi all, I'm back again with a new problem. As per my earlier posts my Mega PC seems to turn on ok, but at that stage I hadn't tried the HDD or floppy drives. I have now tried to boot from both the floppy drive and HDD and I get the same "diskette error" whatever I do (see photo).

I am testing the original floppy and HDD and another floppy drive I have with unfortunately no success in booting from any of them if they are installed in the Mega PC.

However I know that the floppy drives and HDD (and ide cables) work fine as I can boot from all of them if I put them into a different pc.

I have the bios set by restoring defaults and then enabling the fixed disk as type 17 as per the instructions label so I think everything here should be working fine. The floppy drive and fixed disk controller are both shown as active in the bios.

Does anyone have any ideas as to what could be wrong? Is this some sort of drive controller issue?

Thanks

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Reply 212 of 214, by AndrewK2685

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Hm this reminds me some errors I have in some later systems when I enable the "system BIOS cacheable" option.
Try turning off all cache & shadowing associated settings - I don't remember if there are any in MegaPC though

Reply 213 of 214, by Jo22

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Hi! Are the IDE/floppy interfaces the original ones?
I'm asking, because I vaguely remember some issues with the RDY signal line on older PCs.
Some mult-i/o cards with both IDE/floppy had fixes installed to solve the problem.
However, if two separate cards are used or one card and one on-board connector, the issue may show up.

"The main problem in a PC seems to be how to keep the harddisk interface and the floppy interface from colliding on some register addresses.
If the IDE interface is implemented based on some controller system this is of course no problem."

Source: https://www.pjrc.com/tech/8051/ide/wesley.html

Here's a bit more info about RDY, also, or more precisely, DC/RDY (Disk Change/Ready).
The signal seems to be combined on PCs.

https://www.hermannseib.com/english/synths/ppg/wtfloppy.htm

Best regards,
Jo22

Edit: These are just some thoughts. Perhaps the problem is an entirely different one.

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Reply 214 of 214, by keropi

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that looks to me some trace issue if the floppy is defined correctly in BIOS
also make SURE that the stock cable is connected correctly, in both orientation and which end goes where
there is a key in one end of the cable (I mean a filled hole) that goes to the motherboard pins
but you can make the mistake of using this end on the floppy drive and damage one of it's pins that is actually the disk detect signal IIRC so it can lead into this exact problem

🎵 🎧 PCMIDI MPU , Orpheus Soundcard , Action Rewind and Megacard website

💻 WTB Amstrad PC7486SLC-33