CPC464 grey border black screen etc.

[robcfg]

They are basically the same chip, but you can notice that on the 40008, the distribution is a bit different and the cells on the gate array are rectangular instead of square.


I think the original 40007s were getting quite hot so they were changed in order to avoid that. As far as I remember, the 40010 don't have any heatsink but not sure about the 40008.


And it's quite interesting, because at Grimware, they say that 40008 is not pin compatible with 40007:

Amstrad 40008 (CPC 664)
Later, the CPC 664 came out fitted with the 40008 version (and at the same time, the CPC 464 was also upgraded with this version). This version is pinout incompatible with the 40007 (that's why the upgraded 464 of this period have two Gate Array slots on the motherboard, one for a 40007 and one for a 40008).

I'm starting to hate the 664 pcb as they have no year marking nor the GA label like the rest of the boards 


Ok. It seems, according to the service manuals, that the 40007 is the one that is different, so the 464 board has actually the wrong IC in the GA socket.

[Audronic]

Hi All


a Link to 40008 etc in French this May Help ? ?


http://matthieu.benoit.free.fr/pdf/amstrad_videogate-array.pdf.


It has pinouts etc.
Good luck.  Ray

[Bryce]

I'm pretty sure that the 40008 belongs in the 40007 socket, not the 40010 socket.

Bryce.

[Audronic]

HI All


The French link indicates that the 40008 and the 40010 are pin compatible ? ?


Ray

[Bryce]

I have seen a working 464 with 40008 in the 40007 position. In fact the 40010 socket wasn't even installed. My assumption is that the 40008 was a slightly modified 40007 with better thermal management, released because the 40010 wasn't ready yet.


Bryce.

[pledg]

Probably shouldn't do this but I moved the 40008 into the 40010 socket and didn't get any video signal output at all!


I presume both sockets are wired ready to go so no other modifications are needed to be made if you socket and use the 40010 slot?


I have a 40010 from a donor board that I tried in the socket also and it also gave no activity? I have no way of checking whether this 40010 chip is actually good or not.


From my testing the crystal oscillator on my donor board is dead. I may try and swap the crystal from the board I'm currently working on to see whether the donor board will fire up with the 40010 in it?


This board had a visually blown 74LS373 chip on it which I replaced to no effect. Subsequently I discovered the crystal fault.

[Bryce]

Before you go swapping crystals, I'll ask again, because this is important and you haven't answered it yet:
Where are you measuring the clock signal?

Bryce.

[pledg]

The donor board has no clock signal read from the left leg of the crystal and pin 2,3,4 of the IC125 chip.

[Bryce]

That's exactly what I suspected. You can't measure the pins of a crystal, at least not without extremely specific hardware. If you connect a meter or scope to the pins of a crystal, the internal resistance of the meter/scope will collapse the signal and the crystal will stop oscillating, sometimes until you restart the system. Only measure the clock from the CLK pin of the CPU.

Bryce.

[robcfg]

I have seen a working 464 with 40008 in the 40007 position. In fact the 40010 socket wasn't even installed. My assumption is that the 40008 was a slightly modified 40007 with better thermal management, released because the 40010 wasn't ready yet.


Bryce.

Could it be that there are some 464 boards with the gate array slots mislabelled?

According to the pinouts, there's no way a 40008 would work on a 40007 socket.


Also, if the 40008 is pin-compatible with the 40007, then the 664s couldn't work with the 40010, and both 664 boards we have scanned have a 40010...

[Bryce]

I'm not sure what you mean about the 664. They were all 40010 boards weren't they? What has the 40008 got to do with the 664?


Bryce.

[robcfg]

Because the 664 Service Manual mentions IC116, the gate array, as "HSG3130 or HSG3170", being them the 40008 and the 40010.


So theoretically, a 40008 shouldn't work on a 40007 socket.


That's why I think that maybe some boards have mislabelled sockets.

[Bryce]

Or the service manual has yet another mistake to add to its long list?

Bryce.

[gerald]

The French link indicates that the 40008 and the 40010 are pin compatible ? ?

The French are wrong (who said always)     
We had this discussion a while ago : http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/gate-array-decapped!/msg124988/#msg124988
I think Grim tool the info in the scanned book.

[gerald]

Because the 664 Service Manual mentions IC116, the gate array, as "HSG3130 or HSG3170", being them the 40008 and the 40010.

According to my notes :
40007 is ULA8RA023 (bipolar)
40008 is ?
40010 37AA is HSG3170 (CMOS)
40010 36AA is HSG3130 (CMOS)

The decaped picture of the 40008 is in fact a 40007 as it's a  ULA8RA023 (bipolar). The picture is just rotated and difference between them only show artefact of passivation removal, pixel alignment and bonding wires.
The French doc refers it as a RA043 in the chapter header, but as a HSG3130 in the text (and 40007 as RA043). So I would not give any credit to this.

So basically, we miss the 40008 die picture !

[robcfg]

What do you mean the die picture? The one with the metal layer removed?

[robcfg]

I see what you mean, but actually these pictures are from different chips, and I sent Sean a 40007 and a 40008.


Could it be that there's a difference in the type of packaging rather than on the chips themselves?

[pledg]

So on my donor board (Was going to use this for parts but thought lets check it out anyway) it has the 40010 gate array.


I get no clock signal from pin 6 of a new Z80 chip.


When I got this board it had a visibly damaged (Top damaged exposing internals) 74LS373 chip which I have replaced.


I have a good 5v throughout the board?


Any tips???

[gerald]

40008 where taken from this post :http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/gate-array-decapped!/msg135615/#msg135615

I see what you mean, but actually these pictures are from different chips, and I sent Sean a 40007 and a 40008.


Could it be that there's a difference in the type of packaging rather than on the chips themselves?

The packaging would not justify a reference change.

If it was a process change, i would expect the manufacturer to change the mask to differentiate them. Here everything is identical.

Seeing no difference in the die it could be that :
- Sean decapped a second 40007 thinking it was a 40008
- We sent him a 40007 remaked as 40008 (was the 40008 bough on ebay ?)
- or just that the 40007 was done on defective process and amstrad updated the reference to 40008 for the good one. 
The only thing i can currently conclude from picture, 40008 = 40007

side note : we should continue this discussion somewhere else 

[Bryce]

Look for cracks in the copper traces and cracked solder joints first.

Bryce.

[pledg]

Negative can't find anything suspicious... Even lifted the socketed chips to look underneath!

[1024MAK]

When I got this board it had a visibly damaged (Top damaged exposing internals) 74LS373 chip which I have replaced.

Some chips will literally blow apart if subjected to a high enough voltage. I know this, because I once accidentally connected a item of equipment (that has a board with 4000 series logic chips) to a 50V DC supply instead of a 13.8V DC supply (the equipment came in two different versions, one designed for use on 13.8V DC and one designed for use on a 50V DC supply and both used the same type of 5 pin DIN connector). Suffice to say, there was a bang and it was then dead. When I moved it, I heard something rattling about. Inside I found one chip had blown apart. I had to replace all the 4000 series logic chips to get it working again!

So if this CPC board has a blown apart chip, it's possible that either it was fed with the incorrect polarity, someone used an AC supply, or used a DC supply at a much higher voltage. If so, there could be other dead chips on the board.

You really need a working board to work out if your gate array chips (and other socketed chips from your "donor" board) are working or not.

Swapping chips that are suspect (and may well be faulty) into a board that you are attempting to fault find is not something that I recommend. Especially if you may loose track of what happened/happens with each chip...

Mark

[pledg]

Can somebody clarify this please...


If you have a 40007 board with the 40010 socket provision above. It's not just a matter of installing a socket in that 40010 position but other changes are required to the board to make that 40010 socket work?


Does that then render the 40007 socket unusable or can the board then accept the 40007 or the 40010 chip?


I did see another post on this matter but it wasn't answered.

[Bryce]

As far as I know, there are no further changes required. If you install the socket, the board can then work with either a 40007 or a 40010 (but not both at the same time!).

Bryce.

[pledg]

Okay here's a little update!


Unfortunately an 8-bit Xmas was off the cards but I feel progress is being made.


I have installed a working 40007 chip to the board and immediately got a change in output. I have a corrupted colour screen mainly vertical patterns with a visible scrolling output working up from the bottom of the screen. The output colour generally changes with each reset. (see attached typical pic)


I also socketed and replaced all the 74LS153 chips.

Although I'm getting a pulse output from the RAM chips the multiplexors seem to give a high reading on the logic probe no pulsing?

The following are working (NEW):
40007
RAM
CRTC
Z80

Wondering whether the AY or ROM chip could be at fault?


In the process of reseating the Z80 but ran out of sockets so can't test this change yet!


I'm studying the schematics to better understand how this board is working, checking continuity etc. for bad traces but can't find any.

Happy New Year!