CPC6128 Board Problem

[unay]

      Hi,

I broke the motherboard while trying to up with parados. Actually, I can't do solderin. One of my technical friend at work removed the 40015 and replace it with a socket. After that I tried to power up and check if everything was ok. But there was no image on the screen.

While checking the motherboard we realized some paths was damaged. We repair them at the back of motherboard (as you can see the pictures) but still couldn't get any results. Replace th 40015 couldn't work either.You cannot view this attachment.You cannot view this attachment.

Where colud be the problem?

You cannot view this attachment.

[eto]

I can't see the socket in the picture. Was it removed again or ist it just not visible in the picture?

If the socket is still there just remove the 40015 from the socket and see if you can turn it on and get to BASIC. If not, you probably have introduced a short somewhere. Then you need to check if there are any connections that should not be there.

[unay]

Yes, we removed the socket first (we think maybe socket was the problem). And then replace the 40015 again. As I mention before I already tried to run basic when we first remove the 40015. At that point motherboard wont response. Only power led on but no image on the screen. I thought maybe the vga cable is the problem, so i try to "cat" or push "clr" button to get any response driver or the speaker but no results

[eto]

You need to check all connections - either you have introduced a short, or you broke another trace. maybe even to another IC.

Have a look at the left part of the attached picture. This shows how the pins of ROM 40025 and ROM 40015 share the same lanes on the PCB.

E.g. when looking at the new connection you have established (green line in the picture on the right): if you recognized that the connection to PIN 2 on ROM 40015 was no longer there then you probably have ripped off the pad on the motherboard. This not only disconnected the pin of ROM 40015 but also the pin of ROM 40025 (see left part of attached picture). That means the you have to make sure that you also reestablish the connection of pin 2 on the 40025 ROM IC (orange line).

[unay]

Thanks a lot. I'll check it.

[Bryce]

It's highly likely that traces on the upper side of the PCB have been damaged too, so do what eto has already suggested.

Bryce.

[ikonsgr]

Hello from here too unay 
For such difficult repair cases, here is a tool that helps very much:
https://pelrun.github.io/cpc-schematics/index.html

[unay]

Hello from here too unay 
For such difficult repair cases, here is a tool that helps very much:
https://pelrun.github.io/cpc-schematics/index.html

Hi neighbour

Thanks a lot.
It's a great thing.
I hope i'll save this board with cpcwiki hero teams help.

[unay]

put another scratch on the board
using the diagram that ikonsgr sent, i found and fixed 4 more broken paths and now it works.

Many thanks for @eto  , @Bryce , @dodogildo (who directed me to this forum and supported wirh suggestions) and of course @ikonsgr

[McArti0]

Now solder the socket.

[unay]

Now solder the socket.

Yeah )
Unfortunatly i have a ulifac for parados on the way now.