The famous grey screen black frame issue.

[oyshals]

Thanks for all answers so far!

I thought I had found RAM chips with sockets on eBay, but looking more closely, it was for the 6128 plus.

Noe I've googles "MN4164P-15", and found several different ones with this spec. But does the writing on the bottom matter? I have two different kinds: "Japan 52535" and three that says "4D3-15"

I've decided to order all the chips I can, either for use or for spare, as I'm not giving this CPC up!

[pelrun]

MN4164P is just a 4164 manufactured by Panasonic. There were many manufacturers, so you want to search for "4164 DRAM" not just a specific part number. All the other markings are dates/batch codes/manufacturer internal markings that you don't need to worry about.

[Rabs]

Thanks for all answers so far!

I thought I had found RAM chips with sockets on eBay, but looking more closely, it was for the 6128 plus.

Noe I've googles "MN4164P-15", and found several different ones with this spec. But does the writing on the bottom matter? I have two different kinds: "Japan 52535" and three that says "4D3-15"

I've decided to order all the chips I can, either for use or for spare, as I'm not giving this CPC up!

Keep going, they are all fixable. Easier to check RAM failures with the Diagnostic ROM, but you could check for activity on the RAM data out pin. Was there activity on the Z80 M1 pin?

[oyshals]

Thanks for all answers so far!

I thought I had found RAM chips with sockets on eBay, but looking more closely, it was for the 6128 plus.

Noe I've googles "MN4164P-15", and found several different ones with this spec. But does the writing on the bottom matter? I have two different kinds: "Japan 52535" and three that says "4D3-15"

I've decided to order all the chips I can, either for use or for spare, as I'm not giving this CPC up!

Keep going, they are all fixable. Easier to check RAM failures with the Diagnostic ROM, but you could check for activity on the RAM data out pin. Was there activity on the Z80 M1 pin?

It's hard to say, I havent aquired an oscilloscope yet, but I'm getting som activity using the multimeter on Hz, approx 0,8MhZ (not constant). Voltage on this Pin i 2,2V. Edit: This is on the M1 port.

[oyshals]

I am not familiar with the diagnostics rom, would an external on work? like this one: https://www.ebay.com/itm/265807524689?hash=item3de35cf351:g:768AAOSwKz5i55lw&amdata=enc%3AAQAHAAAAsN9%2Bcp7MiyicgOLUBvKfgCncDqycx4h1JQkXrlZ%2Bg8hht4gwR5J7oDHi2tfOHoXRBKbv%2Bpp392LLulmuKKqW5l7troLAARmPpKVKMl8Aib6eQ7z4IVv%2FjrP6sfWFu1yckU6ZmlbxBMmT8sMHQkixqTQlzqeUi7imkl4hZLX7g7HhSgpMTgQINv4y1Bxacyt04C6oRa6dRqh%2B1SSDtySSEILRiQnN9o6rbtVHJHezTr%2Fr%7Ctkp%3ABk9SR47UwsnKYQ

[Rabs]

I have not used the Dandinator so can't really advise but believe so. I use a ROM board which allows it to act as the lower ROM.

[oyshals]

I'm sorry that I'm a bit messy, just trying to check everything.

When studying the back side of the mother board, i noticed that the color of the solderings for IC112 is a bit yellow-ish. It looks more like heat than corrosion. From the schematics, the IC112 seems to be connected to the 16MhZ clock signal, and this signal is good. Is this something to look into?

[Rabs]

I'm sorry that I'm a bit messy, just trying to check everything.

When studying the back side of the mother board, i noticed that the color of the solderings for IC112 is a bit yellow-ish. It looks more like heat than corrosion. From the schematics, the IC112 seems to be connected to the 16MhZ clock signal, and this signal is good. Is this something to look into?

Is it flux residue?

[oyshals]

I think I'll give you all a break until I get the new Z80 and gate array now

Right now I'm leaning a bit towards the Z80 as it is very hot, and the voltage seems to drop a bit with that installed 0,1-0,2V, and I haven't found anything else out of order with my limited tools and experience.

Thanks for all the help so far, I've already learnt alot 

[oyshals]

I have not used the Dandinator so can't really advise but believe so. I use a ROM board which allows it to act as the lower ROM.

Is there a way for me to get my hands on the rom board with a working diagnostic rom? I've searched on eBay, but the only tool I can find is the Dandinator.

[Rabs]

Think the Dandinator is your best option, just I have never used one. I am sure someone else can advise. Don't know if all ROM boards allow a ROM to act as the lower ROM and then you will need to program the ROMS, so a bit more involved.

[Bryce]

My Z80 is a bit hot though, approx 60 degrees C, but I'm thinking thats not abnormal for a CPU?

Check if the Z80 is alive. I would check for clock input, pin 6, and then for activity on M1, pin 27.

Thanks! I'll look into that, last I checked, I found the clock to be correct, the M1 I will check tomorrow.

Another stupid question: Can I do the "piggyback" thing on all kinds of chips, or is this only for the RAM?

Even for RAM I would not recommend piggyback. I doesn't really tell you anything, because it's not always guaranteed to work and it definitely
won't work on a CPU.

Bryce.

[oyshals]

So I got my new Z80 today, and that didn't help. So now I'll just wait for my new Gate Array to arrive from Spain. Then I will order 16 new RAM chips. I will probably spend more money on repairing my 6128 than I would buying one from eBay, but where's the fun in that? Half of this process for me is about the learning 😊

When I finally get it fixed, I will probably have enough spare parts to buy another one and fix it too. 😊

I'm thinking of finally buying an oscilloscope, and learn how to use it (again).
Is it necessary to go for an expensive "industrial" one, or would a cheap one for "hobbies" be sufficient? Anything i should be looking for?

Not giving up!

[oyshals]

One question. Is there a specific name for the sockets which fits the RAM chips? I want to be sure i order the correct sockets so they fit.

[Rabs]

One question. Is there a specific name for the sockets which fits the RAM chips? I want to be sure i order the correct sockets so they fit.

Standard DIP 16 Sockets should do. I get mine from DigiKey.

DILB16P-223TLF

You cannot view this attachment.

Below you can see I replaced two failed ICs in the upper RAM bank.

You cannot view this attachment.

I identified the failed ICs using the Diagnostics ROM and I would always try and identify failed ICs before removing as there is always a risk of damaging the PCB.

[Rabs]

So I got my new Z80 today, and that didn't help. So now I'll just wait for my new Gate Array to arrive from Spain. Then I will order 16 new RAM chips. I will probably spend more money on repairing my 6128 than I would buying one from eBay, but where's the fun in that? Half of this process for me is about the learning 😊

When I finally get it fixed, I will probably have enough spare parts to buy another one and fix it too. 😊

I'm thinking of finally buying an oscilloscope, and learn how to use it (again).
Is it necessary to go for an expensive "industrial" one, or would a cheap one for "hobbies" be sufficient? Anything i should be looking for?

Not giving up!

As you are seeing a clock from the GA, I would suspect it is ok and all indications are you have a RAM failure. The Diagnostics ROM would help you identify this.

I use a Hantek DSO5102P Digital Storage Oscilloscope and I love it.

Below you can see a trace from the Z80 Clock PIN 6.

You cannot view this attachment.

[Rabs]

MN4164P is just a 4164 manufactured by Panasonic. There were many manufacturers, so you want to search for "4164 DRAM" not just a specific part number. All the other markings are dates/batch codes/manufacturer internal markings that you don't need to worry about.

Do the access times matter or are they all going to be fast enough? My 6128s have -12 (120ms) and I replaced with -10 (100ms).

[oyshals]

So I got my new Z80 today, and that didn't help. So now I'll just wait for my new Gate Array to arrive from Spain. Then I will order 16 new RAM chips. I will probably spend more money on repairing my 6128 than I would buying one from eBay, but where's the fun in that? Half of this process for me is about the learning 😊

When I finally get it fixed, I will probably have enough spare parts to buy another one and fix it too. 😊

I'm thinking of finally buying an oscilloscope, and learn how to use it (again).
Is it necessary to go for an expensive "industrial" one, or would a cheap one for "hobbies" be sufficient? Anything i should be looking for?

Not giving up!

As you are seeing a clock from the GA, I would suspect it is ok and all indications are you have a RAM failure. The Diagnostics ROM would help you identify this.

I use a Hantek DSO5102P Digital Storage Oscilloscope and I love it.

Below you can see a trace from the Z80 Clock PIN 6.

You cannot view this attachment.

Thanks! Found some now 👍

After some reading on the forum i checked out the icompplus.com site and ordered some chips. Also ordered the dandanator.

[Rabs]

So I got my new Z80 today, and that didn't help. So now I'll just wait for my new Gate Array to arrive from Spain. Then I will order 16 new RAM chips. I will probably spend more money on repairing my 6128 than I would buying one from eBay, but where's the fun in that? Half of this process for me is about the learning 😊

When I finally get it fixed, I will probably have enough spare parts to buy another one and fix it too. 😊

I'm thinking of finally buying an oscilloscope, and learn how to use it (again).
Is it necessary to go for an expensive "industrial" one, or would a cheap one for "hobbies" be sufficient? Anything i should be looking for?

Not giving up!

As you are seeing a clock from the GA, I would suspect it is ok and all indications are you have a RAM failure. The Diagnostics ROM would help you identify this.

I use a Hantek DSO5102P Digital Storage Oscilloscope and I love it.

Below you can see a trace from the Z80 Clock PIN 6.

You cannot view this attachment.

Thanks! Found some now 👍

After some reading on the forum i checked out the icompplus.com site and ordered some chips. Also ordered the dandanator.

Don't forget to clean the expansion port before using the Dandanator. I use an old ink eraser and then some  isopropanol cleaning fluid.

[oyshals]

So I got my new Z80 today, and that didn't help. So now I'll just wait for my new Gate Array to arrive from Spain. Then I will order 16 new RAM chips. I will probably spend more money on repairing my 6128 than I would buying one from eBay, but where's the fun in that? Half of this process for me is about the learning 😊

When I finally get it fixed, I will probably have enough spare parts to buy another one and fix it too. 😊

I'm thinking of finally buying an oscilloscope, and learn how to use it (again).
Is it necessary to go for an expensive "industrial" one, or would a cheap one for "hobbies" be sufficient? Anything i should be looking for?

Not giving up!

As you are seeing a clock from the GA, I would suspect it is ok and all indications are you have a RAM failure. The Diagnostics ROM would help you identify this.

I use a Hantek DSO5102P Digital Storage Oscilloscope and I love it.

Below you can see a trace from the Z80 Clock PIN 6.

You cannot view this attachment.

Thanks! Found some now 👍

After some reading on the forum i checked out the icompplus.com site and ordered some chips. Also ordered the dandanator.

Don't forget to clean the expansion port before using the Dandanator. I use an old ink eraser and then some  isopropanol cleaning fluid.

Thanks! Looks like I'll have to wait a few weeks now, mail is very slow these days.

Any experience with the icompplus site for Amstrad parts?

[Rabs]

No sorry never used icompplus.

[eto]

Any experience with the icompplus site for Amstrad parts?

I remember that someone on this forum bought some ICs from them and confirmed they are legit. Try a search on the forum or maybe better with Google as the search does not find all posts at the moment. 

[oyshals]

Any experience with the icompplus site for Amstrad parts?

I remember that someone on this forum bought some ICs from them and confirmed they are legit. Try a search on the forum or maybe better with Google as the search does not find all posts at the moment.

Thanks, I actually found the thread on the forum, but I couldn't find any conclusion on wether they worked or not, he seemed to stop posting. I've recieved the gate array, and it looks legit, with Amstrad part number and everything. I'm still waiting for some parts and the Dandinator I ordered for diagnostics before I can test it. I will let you know how it turns out. I reckon if this actually is legit, it will save alot of Amstrads, as they seem to have just about everything.  

[eto]

This is the thread I meant including the conclusion that they are legit: 
https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/gate-array-decapped!/msg219511/#msg219511

[oyshals]

This is the thread I meant including the conclusion that they are legit:
https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/gate-array-decapped!/msg219511/#msg219511

Thanks! That's a relief! I've also ordered the FAL chip on that site, as I managed to break some pins, will try to fix the old one too though.