Cap Leakage

On Tuesday, 18 July 2017 03:27:14 UTC+1, ABLE1 wrote:

Ok, by my count we now have 6 totally different ways to
clean and dry out a board.

Scary too, I might choose the wrong one to do this one board??

Fear not guys................. I will choose wisely.....................

OR

DO THEM ALL just for fun, since I am confident that they all will
be equally effective.

But in what order.................. hmmmmmmmmmm

Les

OK, here's number 7. Put it in a domestic dishwasher then warm room dry for a week.

What does it matter? All you're doing is washing & drying.


NT

 

[ABLE1]

On 7/14/2017 8:45 PM, ABLE1 wrote:

Hello all,

I have a sound amplifier board with what looks like some 25v 220mfd
radial capacitors that appear to have leaked some of the electrolyte on
to the board. The board is easily 20+ years old.

One of the IC chips that is in the area appears to have some corrosion
on the pins.

If someone would be so kind to answer my questions they are as follows:

Is the electrolyte some kind of acid base??

Will washing the board with contact cleaner properly clean
and or neutralize the effects??

I plan on replacing the bad capacitors but want to be sure I am
not missing something. I don't want to replace the chip unless
it is damaged in some way.

Thanks for any hints or tip on this matter.

Have a good day.

Les

Ok, Update and another question.

I removed all the leaking caps plus the others of the same type
and size that had not shown signs of leakage just to be thorough.

I then cleaned the board with some mild detergent, rinsed off
and placed in my pre-heated oven at 220F and then turned off.

Let set in the oven for about 2 hours while it cooled. Pulled
the board out and it looks good.

So far so good. It is now time to install the new caps.

And then it hit me.

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.

Is there some trick that needs to be applied somehow to get this
soldered properly??

Again thanks for any thoughts or suggestions.

Les

 

[Ralph Mowery]

In article <XKNcB.239890$OD2.164460@fx44.iad>, someone@nowhere.net
says...

So far so good. It is now time to install the new caps.

And then it hit me.

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.

Is there some trick that needs to be applied somehow to get this
soldered properly??

Hopefully the holes are waht they call 'plated through' where there is a
path through the hole to the other side that is conductive. Just use
plenty of solder and heat and it should wick to the other side.

 

[ABLE1]

On 7/22/2017 4:30 PM, Ralph Mowery wrote:

In article <XKNcB.239890$OD2.164460@fx44.iad>, someone@nowhere.net
says...


So far so good. It is now time to install the new caps.

And then it hit me.

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.

Is there some trick that needs to be applied somehow to get this
soldered properly??



Hopefully the holes are what they call 'plated through' where there is a
path through the hole to the other side that is conductive. Just use
plenty of solder and heat and it should wick to the other side.

Thanks Ralph,

That was the key point I was missing. I metered each side of the board
on one hole, and yes, I got continuity.

Excellent!! Sooooooooo "Piece of cake".

Thanks again.

Les

 

On Saturday, 22 July 2017 23:42:16 UTC+1, ABLE1 wrote:

On 7/22/2017 4:30 PM, Ralph Mowery wrote:
In article <XKNcB.239890$OD2.164460@fx44.iad>, someone@nowhere.net
says...


So far so good. It is now time to install the new caps.

And then it hit me.

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.

Is there some trick that needs to be applied somehow to get this
soldered properly??



Hopefully the holes are what they call 'plated through' where there is a
path through the hole to the other side that is conductive. Just use
plenty of solder and heat and it should wick to the other side.



Thanks Ralph,

That was the key point I was missing. I metered each side of the board
on one hole, and yes, I got continuity.

Excellent!! Sooooooooo "Piece of cake".

Thanks again.

Les

If it's a piece of cake you'll need to handle it quite carefully when soldering
If electronics ever becomes edible that would solve the disposal issue.


NT

 

[ABLE1]

On 7/22/2017 8:54 PM, tabbypurr@gmail.com wrote:

On Saturday, 22 July 2017 23:42:16 UTC+1, ABLE1 wrote:
On 7/22/2017 4:30 PM, Ralph Mowery wrote:
In article <XKNcB.239890$OD2.164460@fx44.iad>, someone@nowhere.net
says...


So far so good. It is now time to install the new caps.

And then it hit me.

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.

Is there some trick that needs to be applied somehow to get this
soldered properly??



Hopefully the holes are what they call 'plated through' where there is a
path through the hole to the other side that is conductive. Just use
plenty of solder and heat and it should wick to the other side.



Thanks Ralph,

That was the key point I was missing. I metered each side of the board
on one hole, and yes, I got continuity.

Excellent!! Sooooooooo "Piece of cake".

Thanks again.

Les

If it's a piece of cake you'll need to handle it quite carefully when soldering
If electronics ever becomes edible that would solve the disposal issue.


NT

Funny........................

 

[Phil Allison]

ABLE1 wrote:

------------------

Ok, Update and another question.

I removed all the leaking caps plus the others of the same type
and size that had not shown signs of leakage just to be thorough.

** FFS stop using the term "leakage" wrongly.

In electronics, "leakage" refers to current passing through an imperfect insulator.

What you have is caps *leaking electrolyte*.

And then it hit me.

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.

** That makes no sense.

You can see the component side and solder to it.

The reverse side may be a problem to get at, but nearly all PCBs have plated through holes that you can solder from EITHER side.


...... Phil

 

[ABLE1]

On 7/22/2017 9:33 PM, Phil Allison wrote:

ABLE1 wrote:

------------------



Ok, Update and another question.

I removed all the leaking caps plus the others of the same type
and size that had not shown signs of leakage just to be thorough.


** FFS stop using the term "leakage" wrongly.

In electronics, "leakage" refers to current passing through an imperfect insulator.

What you have is caps *leaking electrolyte*.





And then it hit me.

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.


** That makes no sense.

You can see the component side and solder to it.

The reverse side may be a problem to get at, but nearly all PCBs have plated through holes that you can solder from EITHER side.


..... Phil

Thanks Phil,

Mental note made.

Les

 

[John-Del]

On Saturday, July 22, 2017 at 3:32:11 PM UTC-4, ABLE1 wrote:

This is a double sided board. I am concerned that the component
side of the board that is under the capacitor will not be soldered
properly to the leads.

Is there some trick that needs to be applied somehow to get this
soldered properly??

You now know about the plated-through holes, but be aware that while they show continuity now, they may not after soldering. Some manufacturers do not feature sturdy plating in the holes (Samsung is one), and the added leaked electrolyte can aggravate it.

Preheat the board, apply solder flux, use sufficient solder tip heat and carefully insert the capacitors through the holes. Don't force them like you might do on a single sided board.