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General Category => Technical Support => Topic started by: vasilisk on 19:05, 13 January 19

Title: CPC6128 no power in keyboard [FIXED]
Post by: vasilisk on 19:05, 13 January 19
Recently, it came into my hands a second cpc 6128 with color monitor. Monitor works, because I connected it to my other working 6128. The keyboard though is not powering up. After I opened it carefully. I noticed that the 5v socket in the keyboard is a little loose. Could that be the problem? Considering I dont have soldering skills, is it easy to be replaced by someone who knows about electronic repairing? (tv's for example). The part needed is something special or it a common one?


offtopic
I also noticed some visual differences between the two models.
Mine is version G and the other is E

https://www.youtube.com/watch?v=IYCtu2DU-Q4&feature=youtu.be (https://www.youtube.com/watch?v=IYCtu2DU-Q4&feature=youtu.be)


https://imgur.com/a/5bBVwuU (https://imgur.com/a/5bBVwuU) (More detailed images because exceed allowed size)
Title: Re: CPC6128 no power in keyboard
Post by: Bryce on 14:42, 18 January 19
That wobbly socket is definitely your problem, it should be rock solid.

How do the solder joints and tracks on the under side look? You shouldn't need to replace the socket, just reflow (re-heat) the solder joints if the tracks are good. The socket is far away from any sensitive components, so even the most hamfisted beginner could do the repair without causing any damage.
Bryce.
 
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 17:22, 18 January 19
That wobbly socket is definitely your problem, it should be rock solid.

How do the solder joints and tracks on the under side look? You shouldn't need to replace the socket, just reflow (re-heat) the solder joints if the tracks are good. The socket is far away from any sensitive components, so even the most hamfisted beginner could do the repair without causing any damage.
Bryce.


I wanted to check from under, but I can't find a way to remove the keyboard ribbons in order to inspect safely. I dont see anything familiar like for example, in laptops. I pull them out?
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 22:19, 18 January 19
Quote
How do the solder joints and tracks on the under side look?




https://youtu.be/cfkaK3S5Juw (https://youtu.be/cfkaK3S5Juw)
Title: Re: CPC6128 no power in keyboard
Post by: Bryce on 18:40, 19 January 19
Oops, that's a bit of a mess, the tracks are completely torn through... but luckily still easily repaired. Here's what you need to do:

1 - While the socket is still wobbly, try to get some superglue under the socket (between the black plastic and the PCB) and press it down firmly until it has dried.
2 - When it has dried and is solidly in place, make the following solder joints as shown below. The blue wire doesn't need to have insulation, it can be a bare wire. The red wire (5V positive rail) should be insulated wire just in case it can touch anything.

Luckily this is still easily done by a beginner, you are not soldering to anything sensitve that could get damaged by lack of soldering skills. Let us know how you get on.


Bryce.

Edit: Leave a little slack (over-length) in the red wire, to stay away from the screw hole.
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 18:48, 19 January 19
As always thank you for your help. Forgive my lack of knowledge. Is this somekind of "patch" or these joints are meant to be there at the first place.
Title: Re: CPC6128 no power in keyboard
Post by: Bryce on 19:01, 19 January 19
The blue wire is there because it looks like there is a crack all the way around the solder joint. The actual connection is that whole ground plane which stretches between the three points it will connect to. The red wire replaces the track on the top of the PCB which is completely destroyed and this is the simplest way of repairing it. None of them are new connections, they're just replacing what's damaged.

From your original "wobble video" it looks like someone had already tried to repair the top track just with solder, but this would last for about a week or until someone sneezed nearby.

Bryce.
 
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 19:18, 19 January 19
A closer look, just to clarify if any cracks are present.


To be safe, i think i better replace the socket :D
Title: Re: CPC6128 no power in keyboard
Post by: Fessor on 20:04, 19 January 19
What happend here? Is that only dirt or are the tracks broken?
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 20:19, 19 January 19
Propably dirt. I cleaned as thorough as i could


https://imgur.com/a/n7zrE2P (https://imgur.com/a/n7zrE2P)


Sorry for posting outside the forum, but for some reason this specific image is not uploaded (size is less than 4096kb)
Title: Re: CPC6128 no power in keyboard
Post by: Bryce on 09:38, 21 January 19
A closer look, just to clarify if any cracks are present.


To be safe, i think i better replace the socket :D

Replacing the socket is pointless. The socket is fine, the damage is on the PCB.

Bryce.
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 10:12, 21 January 19
Replacing the socket is pointless. The socket is fine, the damage is on the PCB.

Bryce.


Thank you again. The damage is on the upper side or the under?
Title: Re: CPC6128 no power in keyboard
Post by: Bryce on 10:47, 21 January 19
Both actually. The pin at the back of the socket should be in a hole coated in copper, it looks like someone drilled this out and removed the coating. The second damage it the ground plane on the bottom of the board, here the copper layer is cracked.

Bryce.
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 12:33, 21 January 19
So I stabilize the socket and I only solder the joints in red and blue?
Title: Re: CPC6128 no power in keyboard
Post by: Bryce on 13:14, 21 January 19
Yes.

Bryce.
Title: Re: CPC6128 no power in keyboard
Post by: vasilisk on 19:01, 22 January 19
Its alive... 8)
I watched the whole procedure, and I definately couldn't have done it myself.
He desoldered all the old connections and soldered new ones in the socket. He patched the broken line on the upper side with new soldering made by a twisted copper wire. Last, he made the modifications Bryce suggested in the rear. Also he glued the socket down.



Now I have to find a way to fix the drive. I replaced the belt, cleaned the head, greased the worm drive. Nothing. Disc missing

Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: Bryce on 10:07, 23 January 19
Congratulations. The repair on the top isn't really necessary, because the wire on the bottom has already fixed that issue.

Bryce.
Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: vasilisk on 10:47, 23 January 19
Congratulations. The repair on the top isn't really necessary, because the wire on the bottom has already fixed that issue.

Bryce.


He actually told me the opposite. Whoever repaired the top, used bad quality solder. But, I insisted to mod the rear side too, just to be safe.
Anyway thanks again.
Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: Bryce on 10:51, 23 January 19
?? The red wire from the rear socket pin to the power switch jumper is in parallel to the solder repair he did on the top. They connect the exact same two points, just on opposite sides of the board.

Bryce.
 
Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: vasilisk on 10:58, 23 January 19
I know that it is the same, but better safe than sorry. Maybe in the future, the upper solder breaks again.
I also have another problem, but it is of little importance. Sometimes, if I insert the 6-pin all the way in, the font color from yellow turns red. If I insert it half-way it goes back to yellow. The socket is steady. But in comparison to my other 6128, the 6pin does not "secure" 100% inside the socket. It is a little loose. In the other 6128, it is tight.
Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: Bryce on 11:04, 23 January 19
The solder joints on the monitor socket look fine. It's probably just dirt on the contacts. Try giving it a blast of some contact cleaner.

Bryce.
Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: vasilisk on 11:07, 23 January 19
The solder joints on the monitor socket look fine. It's probably just dirt on the contacts. Try giving it a blast of some contact cleaner.

Bryce.


I did, but I only sprayed inside the socket. When I return from work I will spray the 6-pin too. But as I said, in comparison to the other 6128, the 6-pin is a little loose. For example, if I insert it all the way in, and slightly tilt it up, the colors are corrected.
Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: Bryce on 11:32, 23 January 19
If you look into the socket, each cavity has two contacts on either side of the hole. Push these (gently) inwards with a small screwdriver and it will tighten them up.


Bryce.
Title: Re: CPC6128 no power in keyboard [FIXED]
Post by: vasilisk on 11:46, 23 January 19
I will check it out. Thanks