CPC Mainboard Versions

[nocash]

Hi, I've tried to compile a list of all CPC mainboards here, http://cpcwiki.eu/index.php/Mainboard_Versions. There seem to be many-many of versions & sub-versions.

Some pictures are still missing (marked by the red circle with invisible white question mark), and probably further boards exists, which aren't listed at all. I hope some people will add more board numbers & photos!

Oh, and maybe one or two listed versions didn't exist at all (for example, the "CPC6128 version 1.5", does that exist?) (and maybe the drawings in the service manuals were unreleased prototypes?).

[robcfg]

I've been trying to spot differences between the picture of my 664 board and the one in amstrad.cpc.free.fr and they're almost identical but for a couple of details.


As you say it reads MC0005B instead of MC0005A and you can find a resistor attached a bit up from a small IC near the A of Amstrad.

[nocash]

Found another pic of the MC0005B while moving pics from the cpcwiki coppermine gallery. It's better resolution than the free.fr one, and has the extra resistor, too. Btw. good finding! I didn't notice that there was an extra resistor.

Hmmmm, only two 664 boards... is that all? Was the 664 discontinued when the 6128 came out? Or should there be also newer 664 boards existing?

Or, possibly 664s with newer 6128 boards inside (without PAL and with only 64K RAM installed), the 6128 board does have that option, but no idea if it that variant was ever produced?

[nocash]

Does somebody know why there were GX4000 boards without TV modulator?
Maybe Amstrad supported only PAL modulators, but no SECAM ones... so french versions never included modulators?
Or were there special super GX4000 versions with monitor instead modulator?

[arnoldemu]

Does somebody know why there were GX4000 boards without TV modulator?
Maybe Amstrad supported only PAL modulators, but no SECAM ones... so french versions never included modulators?
Or were there special super GX4000 versions with monitor instead modulator?

I am sure this is documented? Maybe it's in the GX4000 user manual? The French version doesn't have modulator. The English version has modulator.

[gerald]

Does somebody know why there were GX4000 boards without TV modulator?
Maybe Amstrad supported only PAL modulators, but no SECAM ones... so french versions never included modulators?
Or were there special super GX4000 versions with monitor instead modulator?

SCART was mandatory for coulor TV sold in France since 1980. I do not know if it was the case in other country.
So Amstrad saved on the PAL encoder and modulator, assuming that french user should have a proper TV set.

[robcfg]

Btw. good finding! I didn't notice that there was an extra resistor.

Thanks man. It took me some minutes just looking at the two pictures just to notice it. Otherwise they seem identical.

What do you think it is the purpose of the resistor? You can see also the bottom side of the MC0005A board here.

By the way, this is a very interesting thread, I'll have to check my 6128's for any of the missing pcb revisions.

[robcfg]

I just scanned the 6128 rev 2 (Z70290 MC0020B) board at 300dpi resolution.

You can find it in the gallery, in the CPC Old Generation article or in the Mainboard revisions article.

[nocash]

Added a description of the resistor on the http://cpcwiki.eu/index.php/Mainboard_Versions page, not sure WHY it connects to those signals. Seems to have something to do with DRAM timings. Maybe they switched to another DRAM manufacturer, and then needed to add that patch.

For the GX4000. The User Manual doesn't really describe it. But if you look at the section with french language: The "parts list" drawing shows a scart cable instead RF cable. Though the french connection example still shows the RF cable.
The Service Manual contains separate RGB/Power schematics for french version, uploaded/extracted that schematic here, http://cpcwiki.eu/index.php/File:Edited_GX4000_French_Schematic.gif

Seems to be no-SECAM-support related. Atari didn't support SECAM too well, too (in their Atari 2600). Maybe, in turn, the french TV market had more TVs that support for RGB than other countries? In germany, Scart became standard between 1980..1990. But, I think most german "scart" TVs only had (and maybe still have) support for Composite (pin19), not for RGB (pin7,11,15). Been wondering about that anyways: How many old/now TVs have RGB support?

[nocash]

> I just scanned the 6128 rev 2 (Z70290 MC0020B) board at 300dpi resolution.
Perfect. Scans are looking even better than photos. I've removed the old photo from the Mainboard Versions page, so there's only one picture per board-version.
Maybe each board-version in the list should also have a link, to a page titled "More pictures of MC0020B" or so?
That way one could add different pics, close-ups, solder-side, etc.

[robcfg]

I don't know if we are going to have that many pictures in order to justify a brand new page for every board revision.


Maybe it would be better to use the <gallery> tag and put the links there to all the images like in here.


I think it would be more comfortable to navigate.

[nocash]

I think (hope) the "Mainboard Versions" page is fine without the "gallery" tag. I have been intentionally not using "galley" there; I wanted the images to be summarized above each other, not next to each other, and without too much blank space between them.

Anyways, yes, for a page with "More Pictures", the "gallery" tag would be the best solution.

Hmmmm, linking to to a single page as "Boards#version"... or separate "Board_version" pages...
Both would have some ups and downs.

"Board_version" might result in many small pages, though they might grow, and then they would become the better solution.

"Boards#version" would be fine. Only, I'd be afraid that somebody could rename the section, for example, from "version" to "Version". Resulting in broken links (unlike page-names, renamed section-names aren't automatically redirected, so links to page#section are a bit fragile).

[Terje_Norway]

Hi,
An interesting thread, and perhaps I could contribute a little to it  .
I have gone through my collection of Amstrad/Schneider CPC computers, and the number of revisions could be high. If You turn a CPC upside down, You'll find the serial number, and on most machines also a MFR'S number or something like that. On many machines it is a yellow label with a letter. 
Obviously MFR means ManuFacturers Revision number.


My computers has the following numbers : 
Machine                         Serial                  Revision
Amstrad CPC464         535-8505506         B
Amstrad CPC464        148218 K31-4X      ??
Amstrad CPC464          10631 K32-4X       E
Amstrad CPC464           06730 -90-12      ??
Amstrad CPC464           24656 -91-01       I
Schneider CPC664       86340 K32-54        A
Amstrad CPC6128       133790 K32-57      A
Amstrad CPC6128       222758 K32-5X      I
Amstrad CPC6128       222742 K32-57      I
Amstrad CPC6128        532 6805853        D
Amstrad CPC6128        542 9310181        K
Schneider CPC6128     136998 K31-56     E
Schneider CPC6128     151494 K32-57     E
Schneider CPC6128     532 6523111        B
464 plus                       531-0782924       A    (ESP)
464 plus                       (board only : MC0122C [7]
6128 plus                     531-0754346       B    (FRA)
6128 plus                     531-0760453       B    (FRA)
GX4000                         735-0919698      B
GX4000                         735-0958752      C
GX4000                         735-0959167      C


I have opened the GX4000's and the letters on the back does match the numbers on the PCB (at least for these machines)
I could make scans of the prints if anyone interested.


Yours


Terje Grind
Norway

[nocash]

Didn't looked underneath my CPC recently. You are right, it's having a big serial sticker, and a small "MFR'S D" sticker, matching with the ending letter of the MC0023D board name. Also found this in internet,
 MFR is an abbreviation for Multi Function Receiver
 MFR is an abbreviation for Multi-Function Radar
 MFR is an abbreviation for Mutual Force Reduction
hmmm, okay, that doesn't make too much sense :-) elsewhere I've found it used for ManuFactuRer, so maybe it just says where the board was manufactured (in case there have been different locations), and the ending A,B,D,I,E letters aren't actually Revisions.
At least the boards are looking the same, no matter of that letter (except for the extra resistor on the patched board, but that's more related to the components, as than to the PCB itself).

Which prints did you mean? Scanning the printer stickers, or the printed PCBs?
PCBs would be interesting! And the corresponding stickers, too.
Btw. great collection - I've only a 664 and 6128 - but no plus :-(

[Gryzor]

Hello Terje,

This is really great info. I'll have to check all my CPCs! Where did you come across it??