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Reflowing...

Started by ||C|-|E||, 12:24, 02 May 16

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||C|-|E||

The other day, when I added the little caps to the RGB output in my Plus some of you guys noticed that some soldering points in the board looked actually dry and it would be nice to reflow them. So, yesterday I decided to carefully go through the whole board. This is what I found.

As you can see, many of the soldering points actually looked dreadful. I do not know if this happened during the wave soldering process or later, but the whole board looked far from nice (imho). It is very different from the conventional 6128 I have in Spain or the board from the CM-14, that was actually very nice. So, I proceeded to reflow most of the soldering points and the look properly wet now.

[attachimg=1]

[attachimg=2]

Since I had the board in the hand, I thought that I would change the caps that had the leads obviously bent, just because I did not really like them the way they were.

[attachimg=3]

And I did it. I actually changed the two big guys (470 pf) but the process, that is usually deadly simple, probed very difficult in this case. It seems that they were put in place before the wave soldering by pressing the leads to make them wider and them hard pressing them through the holes. Then, the leads were bent further to prevent any movement. Summary is that removing the caps from the board was a bloody nightmare and I only changed those two  :-X . The rest of the components seem to be placed in the board using the same method, by the way.

And that was it!  :)

Bryce

I've also noticed from many many repairs that the plus soldering was generally a lot worse quality than the classic CPCs.

Bryce.

||C|-|E||

Soldering is usually very relaxing for me, but it was not this time. Do you have a trick to remove difficult components from the boards, Bryce?  :) At the end, what worked well for me was to cut the leads, removing the cap from the board. Then, I removed as much soldering as I could and finally I gently pushed the leads from the upper part of the board with a hexagon screwdriver while heating the lower part. This way they came out, but it was quite long and difficult process in order not to damage something  :-X

Bryce

Desoldering gun or braid usually. If it's a really tricky part with too many pins and I don't need the part, then I just cut the pins and remove them individually. The most difficult parts are when a pin is connected to a big ground plane and the solder won't melt.

Bryce.

pelrun

I LOVE YOU KITCHEN DESOLDERING GUN!  8)


(actually just got access to a decent one, finally I no longer have to deal with the pain of removing through-hole parts...)

||C|-|E||

I used braid, it works well in my hands 99% of the time, but this board probed to be much more difficult than usual. I mean, the solder was removed but the leads were not coming out easily because they were really stuck inside the hole  :-X .  I always think about getting a good desoldering gun but, as usual, they are expensive  ;D

CraigsBar

Quote from: ||C|-|E|| on 12:24, 02 May 16
The other day, when I added the little caps to the RGB output in my Plus some of you guys noticed that some soldering points in the board looked actually dry and it would be nice to reflow them. So, yesterday I decided to carefully go through the whole board. This is what I found.

As you can see, many of the soldering points actually looked dreadful. I do not know if this happened during the wave soldering process or later, but the whole board looked far from nice (imho). It is very different from the conventional 6128 I have in Spain or the board from the CM-14, that was actually very nice. So, I proceeded to reflow most of the soldering points and the look properly wet now.

[attachimg=1]

[attachimg=2]

Since I had the board in the hand, I thought that I would change the caps that had the leads obviously bent, just because I did not really like them the way they were.

[attachimg=3]

And I did it. I actually changed the two big guys (470 pf) but the process, that is usually deadly simple, probed very difficult in this case. It seems that they were put in place before the wave soldering by pressing the leads to make them wider and them hard pressing them through the holes. Then, the leads were bent further to prevent any movement. Summary is that removing the caps from the board was a bloody nightmare and I only changed those two  :-X . The rest of the components seem to be placed in the board using the same method, by the way.

And that was it!  :)
What rating caps.... And where do they need soldering?
IRC:  #Retro4All on Freenode

||C|-|E||

Quote from: CraigsBar on 23:16, 02 May 16
What rating caps.... And where do they need soldering?

Sorry, I don´t understand well  :) Do you mean the caps I added to the RGB output?  :)

CraigsBar

Quote from: ||C|-|E|| on 23:29, 02 May 16
Sorry, I don´t understand well  :) Do you mean the caps I added to the RGB output?  :)
Yep, that's them. The striped look is starting to annoy me on the LCD scart image :(
IRC:  #Retro4All on Freenode

||C|-|E||

They are these little guys:

[attachimg=1]

Three 220 pf caps between the R, G, B signals and the ground  :) . Bryce is the father of the mod and we discussed it a little bit more in this post:

Picture of modded RGB output in a Plus anyone?

It is actually very easy to do and noticeable  :D

khaz

I've been using this to desolder stuff:
30W 220V 50Hz Electric Vacuum Solder Sucker Desoldering Pump Iron Gun DNS | eBay
Most certainly not the best tool for the job, but one of the cheapest. It works fine, once you get used to how the sucking works.

Audronic

Quote from: pelrun on 14:05, 02 May 16
I LOVE YOU KITCHEN DESOLDERING GUN!  8)


(actually just got access to a decent one, finally I no longer have to deal with the pain of removing through-hole parts...)


Do you have a Manufacturer- Model Number or some pictures.


Thanks    Ray
Procrastinators Unite,
If it Ain't Broke PLEASE Don't Fix it.
I keep telling you I am Not Pedantic.
As I Live " Down Under " I Take my Gravity Tablets and Wear my Magnetic Boots to Keep me from Falling off.

Bryce

Quote from: khaz on 23:50, 02 May 16
I've been using this to desolder stuff:
30W 220V 50Hz Electric Vacuum Solder Sucker Desoldering Pump Iron Gun DNS | eBay
Most certainly not the best tool for the job, but one of the cheapest. It works fine, once you get used to how the sucking works.

That's not regulated, so I wouldn't recommend using it on sensitive parts. But even the regulated ones aren't extremely expensive. Something like this is fine for all work and won't break the bank: Regelbare digitale Entlötstation ZD-915ESD Entlötkolben Entlötpumpe | eBay

Bryce.

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