I don't believe the arcade CGA converters work with digital CGA output from an old PC.

Based on the power documents, the PicoPSUs might not satisfy the peak/max 5v rating.

The Amstrad machine has "maximum rating" of 7 amps on 5v.

the atx to at converters DONT give you -5v. they just change the pinout.

athena power at psu are cheap in usa. I see your in Ireland. amazon uk says 50 quid which is insane.

the gbs boards (which you linked) are good most of the time for converting 15khz cga to 31khz vga.

not 100% of the time, and at one point they changed the memory speed on the gbs board and made some mode timings break etc.

so the GBS boards are hit or miss, but usually ok.

Thanks guy 😀 The Pico would have been nice but it's no deal breaker.

There are adapters with -5, our very own Phil did a review video on them - https://www.youtube.com/watch?v=8QXmxdiNWIs

They have something inline to do the + to - conversion. Does anyone know what that component is?

Do you have any more information on which would be the "best" board for what I need, if that's something you can answer? the most compatible? (were the memory timings etc changes completely for the worse?)

You can easily make -5V from -12V using a 7905 voltage regulator and two capacitors.

You might not actually need -5V at all, if you don't have any expansion cards which need it. It's usually needed for old 4116 DRAM chips, but the PC1512 board uses 4164s which are single-supply. Likewise with -12V - it's normally only needed for (some?) RS232 cards. I'm not 100% sure about the PC1512, but I'm running an IBM 5160 from one of these: http://www.streacom.com/products/zf240-fanles … w-zeroflex-psu/ which doesn't provide -5V or -12V and it's fine.

There are boards that can convert the digital RGBI output from a CGA (or Amstrad PC1512) to the analogue RGB that the arcade converter board needs as input - see http://www.insentricity.com/a.cl/219/cgargbi- … e-commodore-128 for example (although I think Trixter said that some of the colours on that one might be a bit off?). There are also some links on http://www.vcfed.org/forum/showthread.php?374 … -a-Project-Idea which might be useful.

Some older machines generated their -5v line on their motherboards themself by using a 7905 (warning: pinout differs from 7805).

I think CGA (RGB) can also be displayed on SCART equipped television sets. I once saw a schematic for this, I think.
It wasn't a simple cable but it involved several electronic components on a breadboard..

Jo22 wrote:

Some older machines generated their -5v line on their motherboards themself by using a 7905 (warning: pinout differs from 7805).

The Amstrad PC1512 isn't one of them, though - there's a -5V line on the power connector.

Jo22 wrote:

I think CGA (RGB) can also be displayed on SCART equipped television sets. I once saw a schematic for this, I think.
It wasn't a simple cable but it involved several electronic components on a breadboard..

Yep. It's not too difficult - in fact it's the same circuit as needed to convert CGA RGBI to analogue RGB CGA for the arcade converter board (SCART is analogue RGB with ~15kHz line rate). However, the SCART method will only work on a TV which can accept a 60Hz signal (older SCART-equipped TVs might only work at 50Hz).

Thanks reenigne 😀

So the -5v thing is exactly the same as on more "modern" PCs... just for certain expansion cards? That's great! 😀 My knowledge of XT style machines isn't great so I thought it might have been used for something more important.

I think I have a CRT TV that can do 60hz so I might try it that way first, just to make sure everything is working OK, and then move on to getting an LCD/CRT monitor hooked up at some later stage.

Thanks for the help guys 😀

For the power connector:

I have the 14 pin power connector I need to use and was planning to wire this up to a spare 20pin ATX Psu I have, by hacking up a 24 to 20 pin ATX adapter.

The 14 pin connector's pins are REALLY small, and solder cup-less.. Would I be ok soldering some 22 AWG wire to the pins on the connector, running these for a few inches and then soldering the 22AWG to the wire on the 24->20 adapter?

Trying to solder the 24->20 wire directly to the 14pin would be really tricky.

The highest amps seems to be 7amps on the 5v rail but this is two wires combined inside the machine itself, so should be OK right?

I got a Schneider branded Amstrad 1512 in trade today and fooled around with it for a bit. It's snappier then I'd imagined an XT would be. Unfortunately mine came with a monochrome monitor...

I'd really like to use this with a VGA monitor - hooking up a VGA card to it is pretty easy (if you chop off some of the EMI shielding around the ISA slots) - problem is it will still post to the CGA card. Is there a way to disable the CGA card?

kanecvr wrote:

I got a Schneider branded Amstrad 1512 in trade today and fooled around with it for a bit. It's snappier then I'd imagined an XT […]
Show full quote

I got a Schneider branded Amstrad 1512 in trade today and fooled around with it for a bit. It's snappier then I'd imagined an XT would be. Unfortunately mine came with a monochrome monitor...

I'd really like to use this with a VGA monitor - hooking up a VGA card to it is pretty easy (if you chop off some of the EMI shielding around the ISA slots) - problem is it will still post to the CGA card. Is there a way to disable the CGA card?

Err, is CGA built-in? Maybe there's a jumper or a dip-switch to disable it?

kanecvr wrote:

I got a Schneider branded Amstrad 1512 in trade today and fooled around with it for a bit.

Congratulations! Looks like it is in good shape! 😀

kanecvr wrote:

It's snappier then I'd imagined an XT would be. Unfortunately mine came with a monochrome monitor...

Because it is. It does contain an 8086 processor with 16Bit data bus.

Bye the way, did it come with the floppies, too ? If it did, do you have any use for the utilities from the 5th diskette ?
I have them. In case you're interested, just say so. They do conatin some fixed-disk utilities for DOS and DOS Plus..

kanecvr wrote:

I'd really like to use this with a VGA monitor - hooking up a VGA card to it is pretty easy (if you chop off some of the EMI shielding around the ISA slots) - problem is it will still post to the CGA card. Is there a way to disable the CGA card?

IMHO, the enhanced CGA card is the one that makes it special. The GEM version uses this for a 640x200 mode. Some games use that CGA, too.
And I once read that the internal CGA does scan-doubling, making normal CGA games to appear less striped.
If you plug in an VGA card, it becomes just an ordinary XT clone. Besides, the power supply is in the monitor. So you have to built another PSU yourself.

Edit: http://www.old-computers.com/museum/computer.asp?c=183

It's a 1512 party in here lately 😁

From what I've read, it isn't possible to disable the CGA - a second card will always function as a secondary output (like dual screen?)

I'd say investigate though! I'm also going to try rig something up to convert CGA to VGA as my machine didn't come with a monitor.

Jo22 wrote:

Bye the way, did it come with the floppies, too ? If it did, do you have any use for the utilities from the 5th diskette ?
I have them. In case you're interested, just say so. They do conatin some fixed-disk utilities for DOS and DOS Plus..

It didn't come with any floppies unfortunately... I could use the setup disk for the machine if you happen to have an image of it and are willing to share.

Jo22 wrote:

IMHO, the enhanced CGA card is the one that makes it special. The GEM version uses this for a 640x200 mode. Some games use that CGA, too.
And I once read that the internal CGA does scan-doubling, making normal CGA games to appear less striped.
If you plug in an VGA card, it becomes just an ordinary XT clone. Besides, the power supply is in the monitor. So you have to built another PSU yourself.

I noticed the PSU is in the monitor, but a previous owner added a kill switch for the monitor itself witch allows operation of the PC only - handy. It makes me thing a previous owner had a color monitor compatible with the machine or added another video card.

Normally I'd have nothing against using CGA, but my machine came with a Monochrome monitor, and I'd really like to play games in color on it - whether it's CGA, EGA or VGA (preferably the latter two).

If I had a working compatible color monitor I'd use that and be done with it.

sirlemonhead wrote:

It's a 1512 party in here lately 😁

From what I've read, it isn't possible to disable the CGA - a second card will always function as a secondary output (like dual screen?)

I'd say investigate though! I'm also going to try rig something up to convert CGA to VGA as my machine didn't come with a monitor.

The problem is the second card would run in Monochrome mode... thus my problem remains...

sirlemonhead wrote:

From what I've read, it isn't possible to disable the CGA

My understanding is that it's possible, but doing it involves cutting some tracks on the board.

Jo22 wrote:

And I once read that the internal CGA does scan-doubling, making normal CGA games to appear less striped.

I don't think it does any scan-doubling - the timings are just the standard CGA ones from what I understand. Do you remember where you read that? I may check tomorrow, since I was thinking of getting mine out anyway to check something else.

reenigne,

Do you know anything about how the 'black' pin on the video is supposed to be handled?

kanecvr wrote:

Jo22 wrote:

Bye the way, did it come with the floppies, too ? If it did, do you have any use for the utilities from the 5th diskette ?
I have them. In case you're interested, just say so. They do conatin some fixed-disk utilities for DOS and DOS Plus..

It didn't come with any floppies unfortunately... I could use the setup disk for the machine if you happen to have an image of it and are willing to share.

Sorry, I can't provide you with the images of the originals, but I can give you a list of the install media.
The only image I could make available is the 5th one (dark purple), as it is merely a driver/utility diskette without commercial stuff.
Anyway, that one is the rarest of them, I think - It took me several years (!) to get hold on a copy of such a disk..
Perhaps it was probably only given to Amstrad users who bought an PC with such a HDD installed.

-= Disks =-
DISC1, MS-DOS 3.2 (red)
DISC2, GEM (blue)
DISC3, GEM DESKTOP and GEM BASIC (green)
DISC4, DOS Plus and GEM-PAINT (yellow)
DISC5, Fixed-Disk installation and service diskette (purple)

Except for the utilities and the GEM graphics driver, there's little that can't be replaced by generic versions.
Vanilla MS-/PC-DOS 3.x should run fine on the PC1512, too.

But back to the 5th floppy.. This floppy has got several useful files for DOS Plus v1.2 on it.
Like HDFORMAT.COM (fixed disk format utility), FIXLDR.COM (writes DOSPlus boot sector, also for dual-boot with DOS ?),
PARK.COM (HDD parking program from Amstrad), SYS2DIR.EXE (writes DOSPlus boot sector) and NVRPAT2.COM (unkwown purpose).

Other programs are BACKUP.EXE, RESTORE.EXE, SDIR.CMD (Super DIR ?) and BACKUP.CMD (Backup/Restore).
The COM files do also work on normal MS-DOS. Only the CMD files are a DOS Plus exclusive
('cause it really is CP/M with a DOS emulator).

Oh, and there's something more important! Some of these programs (FIXLDR ?) do only work when they find PC-DOS (!)
system files, like IBMBIO.COM and IBMDOS.COM! So it's good to have a copy of PC-DOS 3.30, as well. 😀

Since this is a thread about the PC1512, I hope it's okay to attach a little zip file for PC1512 owners here.
It contains hardware specific utilities that where never sold. Perhaps it can also be useful for PC1640 users.

Edit: The automated installation program is CONFIG.BAT. It will ask for the remaining floppies and then install both MS-DOS/DOS Plus and GEM.
The attached archive contains the Schneider version, but it should also work just fine with the rest of the Amstrad disk sets..
DOS Plus should be able to handle fixed disk drives which were pre-formatted/partitioned with DOS 3.x.