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General Category => Amstrad CPC hardware => Topic started by: Lulubull on 22:29, 08 January 20

Title: Help to restore a old CPC 6128
Post by: Lulubull on 22:29, 08 January 20
Hello,
I am new on the forum and i would like to "restore" my CPC 6128. I have already saw some topics with the problem i have and i have saw, this problem is the RAM. I need your help because i don't understand the history with the PIN. The CPC  Thanks in advance.
Best Regards.
P.S : Sorry for my bad english. I am an French student.
Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 09:36, 09 January 20
Hi Lulubull,
      yes, that looks like a RAM issue. Do you have the equipment/skills to replace the RAM? Or are you looking for someone to do the repair? If you want someone to swap the RAM you can send it to me.

Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 09:51, 09 January 20
Hi Bryce,
Thanks to reply me. In fact, i have the equipment to do that. I understand easily with pictures so i can do that. I have a soldering iron to replace the RAM. If i need other things to replace the RAM, tell me. I can buy stuff for that.
Best regards.
Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 10:13, 09 January 20
Well you need to firstly find out which RAM chip is causing the problem. Then all you need is a new RAM chip and IC socket.

Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 10:19, 09 January 20
Ok, how i check a RAM chip ?
And i supposed the first RAM ship is the IC119 to IC126.
BR
Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 10:25, 09 January 20
Actually no, the lower 64K is on the right, IC127 - IC134. Unless one or more RAMs are getting very hot, you will need some way of replacing the firmware ROM with an EPROM containing Geralds RAM Test to know exactly which chip has failed.

Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 10:46, 09 January 20
To replace the RAM, where can i buy it ?
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 10:48, 09 January 20
And i have reed on another post, you said we can switch the lower and the upper because one of them is not necessary to boot the CPC. I'm wrong ?
Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 10:50, 09 January 20
They're not made any more, so ebay is the only place to get them.
It doesn't sound as if you have much electronics experience. Are you confident that you can swap out RAMs without damaging the computer further?

Yes, you can replace the PAL chip with some wire bridges and that will cause the CPC to use the upper 64K instead.


Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 10:57, 09 January 20
My father have much more skill in electronics. So when i understand the different step, he replace the RAM for me.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 11:03, 09 January 20
I check out for ebay and i see that's difficult to find the RAM. If we switch the upper and the lower, they have any dangers or issues if you launch games or other programms ?
If not, i think i do this think if it's possible of course.
BR
Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 11:07, 09 January 20
Swapping is normally only done for test purposes, but you could do it permanently. However, you then only have a 64K computer, so any games needing more RAM will not work.

Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 11:10, 09 January 20
I have see on ebay some RAM extension for 6128. Can work with games ?

Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 11:12, 09 January 20
No RAM expasion will work after you have removed the PAL chip.

Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 11:18, 09 January 20
So the only way is to replace the PAL chip. The hardest part is to find a working PAL ship on ebay.
Title: Re: Help to restore a old CPC 6128
Post by: TotO on 11:25, 09 January 20
I have MP you in french to see if I can help.
Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 11:26, 09 January 20
You don't need to replace the PAL. It most likely works fine. You only replace the PAL with wire links to swap the upper/lower memory banks for test purposes. While the links are in place, the machine will only be 64K and RAM expansions will not work.

All you need to do is establish which RAM chip is bad and replace that.


Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: TotO on 11:32, 09 January 20
My idea is to send him a diagnostic board to display the faulty RAM without alterate anything on the CPC.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 11:57, 09 January 20
Thanks for your help Bryce i'm going check the idea of TotO.
best regards
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 17:40, 26 January 20

Hello everyone,
Sorry for the late but with TotO, we found the problem. In fact, the problem is due to a RAM Ship. But we haven't found the exact RAM Ship that isn't working. I upload 2 photos. I can't find the RAM Ship. If anyone could help me, I really thank him. Thank you in advance.
Best regards.
Title: Re: Help to restore a old CPC 6128
Post by: Bryce on 17:44, 26 January 20
Maybe @gerald (https://www.cpcwiki.eu/forum/index.php?action=profile;u=250) can confirm this, but as far as I know, that means IC127 (Top right chip) is bad.

Bryce.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 18:05, 26 January 20
Thanks for your help Bryce. If you need more pictures or others about the cpc, tell me.
Br
Title: Re: Help to restore a old CPC 6128
Post by: gerald on 18:08, 26 January 20
Maybe @gerald (https://www.cpcwiki.eu/forum/index.php?action=profile;u=250) can confirm this, but as far as I know, that means IC127 (Top right chip) is bad.

Bryce.
I confirm.Bits are displayed from top in order bit 7 to bit 0.Here bit 0 is failing, which on bank 0 is IC127.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 18:19, 26 January 20
Thanks you Gerald for your help. I see with TotO for replace the RAM Ship IC127. If the Amstrad work, i tell you.
Best Regards.
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 16:33, 09 February 20
Hello everyone,
I come with good news. My CPC 6128 work again ! Finally, i change the IC127 and replace by a new one. The game work with no problems. I post 2 pictures below this post. TotO help me a lot with this problem. Thanks to everybody for the help !
Best Regards.
Title: Re: Help to restore a old CPC 6128
Post by: ibisum on 19:35, 09 February 20
Cool thread!  I want to do the same with a dead CPC6128 of my own, which has a very hot set of RAM chips (right hand side) when its turned on for a few seconds.
Am I correct in understanding that a ROM debug chip was used to determine the bad physical RAM component?
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 19:59, 09 February 20

Hi,
Yes. The thing I used is a little chip that I plugged into my CPC and when I turned on the CPC, the monitor tells me which RAM chip is "dead";)
br
Title: Re: Help to restore a old CPC 6128
Post by: ibisum on 22:42, 09 February 20
Ah, cool, any chance you could tell me the chip and maybe details about if it can be bought somewhere - or is it a ROM image I should burn, or something?

I have an M4 board, is it not possible to load a debug ROM into it that will serve a similar purpose?   Just guessing ..
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 22:47, 09 February 20
Hi,
Contact TotO. He tell you more to fix that. I can't tell you more about that. I'm a noob  ???
Br
Title: Re: Help to restore a old CPC 6128
Post by: TotO on 23:52, 09 February 20
I have an M4 board, is it not possible to load a debug ROM into it that will serve a similar purpose?   Just guessing ..
I think yes. You have to use the gerald's RAM test program to boot from the M4 ROM by installing it as alternative firmware.
http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/quick-and-dirty-ram-test-for-cpc/ (http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/quick-and-dirty-ram-test-for-cpc/)
Title: Re: Help to restore a old CPC 6128
Post by: ibisum on 12:44, 10 February 20
Cool, thanks guys - I will try to use my M4 card to debug what's up, and hopefully can report a newly recovered CPC6128 some time soon .. in any case, I've also got Bryce on the wire, who will surely sort it out if we newbies can't.  Looking forward to recovery!
Title: Re: Help to restore a old CPC 6128
Post by: Lulubull on 14:10, 10 February 20
Good luck  ;)
br