Cap Leakage

[ABLE1]

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

 

[tom]

"ABLE1" <someone@nowhere.net> wrote in message
news:NAdaB.89557$5A2.42585@fx28.iad...

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

Remove the capacitors and wash the board with detergent and warm water. Use
a brush to scrub where there is corrosion.

Dry in oven at 50-60 °C for several hours.

 

[Phil Allison]

ABLE1 wrote:

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

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??

** It's usually ethylene glycol plus boric acid and loves to attack copper.

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

** Contact cleaner is undefined, can be damn near anything.

I use a "Circuit Boaord Cleaner" that has a combination of hydrocarbon solvents and dries quickly.

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.

** Clean it up best you can and watch out if electrolyte has gone underneath.

I have found a small fibreglass brush useful.

http://au.element14.com/duratool/d02266/pen-pcb-cleaning-fibreglass-4mm/dp/2102028

Really bad cases may need immersion in hot, detergent water to come good.



..... Phil

 

On Saturday, 15 July 2017 01:51:00 UTC+1, tom wrote:

"ABLE1" <someone@nowhere.net> wrote in message
news:NAdaB.89557$5A2.42585@fx28.iad...
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



Remove the capacitors and wash the board with detergent and warm water. Use
a brush to scrub where there is corrosion.

Dry in oven at 50-60 °C for several hours.

Detergents also tend to be corrosive long term so clean it off well.


NT

 

[ABLE1]

On 7/14/2017 11:31 PM, Phil Allison wrote:

ABLE1 wrote:

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


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??


** It's usually ethylene glycol plus boric acid and loves to attack copper.


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


** Contact cleaner is undefined, can be damn near anything.

I use a "Circuit Boaord Cleaner" that has a combination of hydrocarbon solvents and dries quickly.


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.


** Clean it up best you can and watch out if electrolyte has gone underneath.

I have found a small fibreglass brush useful.

http://au.element14.com/duratool/d02266/pen-pcb-cleaning-fibreglass-4mm/dp/2102028

Really bad cases may need immersion in hot, detergent water to come good.



.... Phil

Tom, NT, Phil, Thanks for all the input.

I get the idea on cleaning. BTW as for "Contact Cleaner" I was
referring to this one.

https://www.zoro.com/crc-electronic-component-cleaner-13-oz-02200/i/G8578595/
Or similar, but may not be the most desired.

Phil, as for the term "Circuit Board Cleaner" is there a specific brand
that you use??

Presently searching for replacement caps. Once I acquire them I will
dive into this project.

Another question: Concerning the chip that has been effected. Can or
could the electrolyte leach into the chips at the pins and cause
problems with the chip in some way?? Or is the chip considered
hermetically sealed is some fashion??

Thanks again!! Do appreciate the insight.

Les

 

On Saturday, 15 July 2017 13:09:57 UTC+1, ABLE1 wrote:

Tom, NT, Phil, Thanks for all the input.

I get the idea on cleaning. BTW as for "Contact Cleaner" I was
referring to this one.

https://www.zoro.com/crc-electronic-component-cleaner-13-oz-02200/i/G8578595/
Or similar, but may not be the most desired.

Phil, as for the term "Circuit Board Cleaner" is there a specific brand
that you use??

Presently searching for replacement caps. Once I acquire them I will
dive into this project.

Another question: Concerning the chip that has been effected. Can or
could the electrolyte leach into the chips at the pins and cause
problems with the chip in some way?? Or is the chip considered
hermetically sealed is some fashion??

Thanks again!! Do appreciate the insight.

Les

if they weren't sealed they wouldn't last long


NT

 

[ABLE1]

On 7/15/2017 8:14 AM, tabbypurr@gmail.com wrote:

On Saturday, 15 July 2017 13:09:57 UTC+1, ABLE1 wrote:

Tom, NT, Phil, Thanks for all the input.

I get the idea on cleaning. BTW as for "Contact Cleaner" I was
referring to this one.

https://www.zoro.com/crc-electronic-component-cleaner-13-oz-02200/i/G8578595/
Or similar, but may not be the most desired.

Phil, as for the term "Circuit Board Cleaner" is there a specific brand
that you use??

Presently searching for replacement caps. Once I acquire them I will
dive into this project.

Another question: Concerning the chip that has been effected. Can or
could the electrolyte leach into the chips at the pins and cause
problems with the chip in some way?? Or is the chip considered
hermetically sealed is some fashion??

Thanks again!! Do appreciate the insight.

Les

if they weren't sealed they wouldn't last long


NT

Thanks NT,

I got it. Was just wondering if the "seal" would be
effected by the leaking electrolyte is some way.

As a general question on these capacitors that leaked.
Given the age (20+ years) would it be that they would
have been effected by a power surge or just old age.

There are other radial caps on the board of the same size
and value that do not show any leakage.

I am asking in respect that given the condition should I
just replace them all or only those that have leaked??

For me this is more of a fun experiment of sorts. I have
been working with various electronics for 40++ years or so.
Running my own business for the past 29 years.

I have in the past but rarely have I gotten down to board level.
As you can guess, if a component or board failed it was trash it
and install a new. For critical devices it is not worth the time
and liability to play around with board components.

This project is quite different. I have already replaced the sound
board with another and the repair project is completed.

Just waiting to be paid.

I just want to see if my observation as to the condition of the caps was
the real problem and can I fix it by doing a little board de-soldering,
etc. Already on Digi-Key trying to source replacements.

Again, thanks for the hints. Have a good rest of your weekend.

Les

 

[Jon Elson]

ABLE1 wrote:

Another question: Concerning the chip that has been effected. Can or
could the electrolyte leach into the chips at the pins and cause
problems with the chip in some way?? Or is the chip considered
hermetically sealed is some fashion??

The typical commercial chips are epoxy molded around the lead frame and IC.
So, the "seal" is just metal leads molded into the plastic body. Given
enough time and humidity, it is possible for the leaked electrolyte or any
other corrosive stuff to work its way along the lead and get to the bonding
wires or the IC itself. Not real common, but it CAN happen.

Military/aerospace chips are more hermetic, with kovar leads fused into a
glass seal. But, enough corrosive stuff can get into those, too. it just
takes longer.

Jon

 

[ABLE1]

On 7/15/2017 2:13 PM, Jon Elson wrote:

ABLE1 wrote:



Another question: Concerning the chip that has been effected. Can or
could the electrolyte leach into the chips at the pins and cause
problems with the chip in some way?? Or is the chip considered
hermetically sealed is some fashion??
The typical commercial chips are epoxy molded around the lead frame and IC.
So, the "seal" is just metal leads molded into the plastic body. Given
enough time and humidity, it is possible for the leaked electrolyte or any
other corrosive stuff to work its way along the lead and get to the bonding
wires or the IC itself. Not real common, but it CAN happen.

Military/aerospace chips are more hermetic, with kovar leads fused into a
glass seal. But, enough corrosive stuff can get into those, too. it just
takes longer.

Jon

Thanks Jon,

I understand. At this point I am going to replace the caps and see what
happens. Hopefully that will be the complete fix.

Les

 

On Saturday, 15 July 2017 17:25:07 UTC+1, ABLE1 wrote:

On 7/15/2017 8:14 AM, tabbypurr wrote:
On Saturday, 15 July 2017 13:09:57 UTC+1, ABLE1 wrote:

Tom, NT, Phil, Thanks for all the input.

I get the idea on cleaning. BTW as for "Contact Cleaner" I was
referring to this one.

https://www.zoro.com/crc-electronic-component-cleaner-13-oz-02200/i/G8578595/
Or similar, but may not be the most desired.

Phil, as for the term "Circuit Board Cleaner" is there a specific brand
that you use??

Presently searching for replacement caps. Once I acquire them I will
dive into this project.

Another question: Concerning the chip that has been effected. Can or
could the electrolyte leach into the chips at the pins and cause
problems with the chip in some way?? Or is the chip considered
hermetically sealed is some fashion??

Thanks again!! Do appreciate the insight.

Les

if they weren't sealed they wouldn't last long


NT


Thanks NT,

I got it. Was just wondering if the "seal" would be
effected by the leaking electrolyte is some way.

as said it's epoxy on metal so not likely.

As a general question on these capacitors that leaked.
Given the age (20+ years) would it be that they would
have been effected by a power surge or just old age.

old age and/or lack of power

There are other radial caps on the board of the same size
and value that do not show any leakage.

I am asking in respect that given the condition should I
just replace them all or only those that have leaked??

Given the bad state of some caps it's likely there are others that have gone high ESR and/or low capacity but not leaked. Most folk would replace the lot. You can get a ÂŁ12 chinese component tester that'll tell you real capacity & ESR. See ebay, amazon, banggood etc.


NT

For me this is more of a fun experiment of sorts. I have
been working with various electronics for 40++ years or so.
Running my own business for the past 29 years.

I have in the past but rarely have I gotten down to board level.
As you can guess, if a component or board failed it was trash it
and install a new. For critical devices it is not worth the time
and liability to play around with board components.

This project is quite different. I have already replaced the sound
board with another and the repair project is completed.

Just waiting to be paid.

I just want to see if my observation as to the condition of the caps was
the real problem and can I fix it by doing a little board de-soldering,
etc. Already on Digi-Key trying to source replacements.

Again, thanks for the hints. Have a good rest of your weekend.

Les

 

[Phil Allison]

ABLE1 wrote:

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

Tom, NT, Phil, Thanks for all the input.

I get the idea on cleaning. BTW as for "Contact Cleaner" I was
referring to this one.

https://www.zoro.com/crc-electronic-component-cleaner-13-oz-02200/i/G8578595/
Or similar, but may not be the most desired.

Phil, as for the term "Circuit Board Cleaner" is there a specific brand
that you use??

** The brand I use is " RF " ( Richard Foot Pty Ltd ), available only here in Australia, AFAIK

The CRC product you linked is likely similar - simple, fast evaporating hydrocarbon solvent.


..... Phil

 

[ABLE1]

On 7/16/2017 7:51 AM, Phil Allison wrote:

ABLE1 wrote:

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


Tom, NT, Phil, Thanks for all the input.

I get the idea on cleaning. BTW as for "Contact Cleaner" I was
referring to this one.

https://www.zoro.com/crc-electronic-component-cleaner-13-oz-02200/i/G8578595/
Or similar, but may not be the most desired.

Phil, as for the term "Circuit Board Cleaner" is there a specific brand
that you use??



** The brand I use is " RF " ( Richard Foot Pty Ltd ), available only here in Australia, AFAIK

The CRC product you linked is likely similar - simple, fast evaporating hydrocarbon solvent.


.... Phil

Thanks Phil,

Most impressive....................

and they do Chocolate as well.............

COOL!!!


Les

 

On Fri, 14 Jul 2017 20:51:30 -0400, "tom" <tmiller11147@verizon.net>
wrote:

"ABLE1" <someone@nowhere.net> wrote in message
news:NAdaB.89557$5A2.42585@fx28.iad...
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



Remove the capacitors and wash the board with detergent and warm water. Use
a brush to scrub where there is corrosion.

Dry in oven at 50-60 °C for several hours.

I dont know if I'd place any electronics in an oven. Heat destroys
components. Just sit it in the sun on a sunny day and it will dry. I
have washed computer motherboards, including the power supplies, and
hosed them off. (to remove all that dirt that builds up on that stuff),
then left them out in the sun for a full day to dry, and they always
work just fine.

 

[Ralph Mowery]

In article <irfnmclaqsfrc3do6o7j9vrt11157fgaie@4ax.com>,
oldschool@tubes.com says...

I dont know if I'd place any electronics in an oven. Heat destroys
components. Just sit it in the sun on a sunny day and it will dry. I
have washed computer motherboards, including the power supplies, and
hosed them off. (to remove all that dirt that builds up on that stuff),
then left them out in the sun for a full day to dry, and they always
work just fine.

My oven will not regulate that low, so I put the wet equipment in a car
that is out in the sun in the summer.

 

[ABLE1]

On 7/16/2017 6:48 PM, Ralph Mowery wrote:

In article <irfnmclaqsfrc3do6o7j9vrt11157fgaie@4ax.com>,
oldschool@tubes.com says...



I dont know if I'd place any electronics in an oven. Heat destroys
components. Just sit it in the sun on a sunny day and it will dry. I
have washed computer motherboards, including the power supplies, and
hosed them off. (to remove all that dirt that builds up on that stuff),
then left them out in the sun for a full day to dry, and they always
work just fine.

My oven will not regulate that low, so I put the wet equipment in a car
that is out in the sun in the summer.

Ah ha!! The discussion continues....................... COOL!!!

 

[Phil Allison]

Ralph Mowery wrote:

I dont know if I'd place any electronics in an oven. Heat destroys
components. Just sit it in the sun on a sunny day and it will dry. I
have washed computer motherboards, including the power supplies, and
hosed them off. (to remove all that dirt that builds up on that stuff),
then left them out in the sun for a full day to dry, and they always
work just fine.

My oven will not regulate that low, so I put the wet equipment in a car
that is out in the sun in the summer.

** The trick is to bring the oven up to about 100C, then turn it off.

Place the item inside and close the door, it will heat to about 75C and be dry as a bone in 15 minutes. Take it out and let it cool.

75C is not hazardous to electronic components.


..... Phil

 

[ABLE1]

On 7/16/2017 8:28 PM, Phil Allison wrote:

Ralph Mowery wrote:



I dont know if I'd place any electronics in an oven. Heat destroys
components. Just sit it in the sun on a sunny day and it will dry. I
have washed computer motherboards, including the power supplies, and
hosed them off. (to remove all that dirt that builds up on that stuff),
then left them out in the sun for a full day to dry, and they always
work just fine.

My oven will not regulate that low, so I put the wet equipment in a car
that is out in the sun in the summer.



** The trick is to bring the oven up to about 100C, then turn it off.

Place the item inside and close the door, it will heat to about 75C and be dry as a bone in 15 minutes. Take it out and let it cool.

75C is not hazardous to electronic components.


.... Phil

More CHOICES............... I love it!!!

Thanks Phil,

Les

 

I used to have a different approach. This happened to Mitsubishi TVs alot because of electrolyte leaks. But I had a different problem sometimes and that was coolant leaks. Both substances act pretty much the same. At first, on the board they are pretty innocuous, but after a little time and voltage put across them they became corrosive and conductive.

But the caps themselves, I stopped changing them. Maybe they're doe leaking..

I took the board out for this. I started with acetone, and then alcohol. Brushed the hell out of it both times. Then rinsed it in the sink in hot water. This place had restaurant hot water. Remember to flood and brush both sides of the board. Then dry it with a hair dryer. Dry both sides, that gets the trapped water out of your SMDs.

Repeat. I shit you not. And after that inspect and make sure you see no wet spots after the board is supposedly dry. That might be the remains of the chemical.

That's how I used to do it. It worked.

 

[John-Del]

On Monday, July 17, 2017 at 9:37:10 PM UTC-4, jurb...@gmail.com wrote:

I used to have a different approach. This happened to Mitsubishi TVs alot because of electrolyte leaks. But I had a different problem sometimes and that was coolant leaks. Both substances act pretty much the same. At first, on the board they are pretty innocuous, but after a little time and voltage put across them they became corrosive and conductive.

But the caps themselves, I stopped changing them. Maybe they're doe leaking.

I took the board out for this. I started with acetone, and then alcohol. Brushed the hell out of it both times. Then rinsed it in the sink in hot water. This place had restaurant hot water. Remember to flood and brush both sides of the board. Then dry it with a hair dryer. Dry both sides, that gets the trapped water out of your SMDs.

Repeat. I shit you not. And after that inspect and make sure you see no wet spots after the board is supposedly dry. That might be the remains of the chemical.

That's how I used to do it. It worked.

Years ago RCA sent a bulletin about the glycol leakage in the 195 series. They recommended an ammonia detergent. I used to buy tons of Parson's Sudsy Ammonia and mix it about 25-75 detergent to water. Remove anything that could trap liquid such as the flyback, smps transformer, cored inductors, etc. and give them a long hot bath in the brew. Rinse several times and put the board in the hot box for several hours. The boards looked like new and all problems caused by stray conductance disappeared. Not sure how the sudsy ammonia detergent works with electrolyte leakage but for the coolant leaks it was the bomb.

 

[ABLE1]

On 7/17/2017 9:53 PM, John-Del wrote:

On Monday, July 17, 2017 at 9:37:10 PM UTC-4, jurb...@gmail.com wrote:
I used to have a different approach. This happened to Mitsubishi TVs alot because of electrolyte leaks. But I had a different problem sometimes and that was coolant leaks. Both substances act pretty much the same. At first, on the board they are pretty innocuous, but after a little time and voltage put across them they became corrosive and conductive.

But the caps themselves, I stopped changing them. Maybe they're doe leaking.

I took the board out for this. I started with acetone, and then alcohol. Brushed the hell out of it both times. Then rinsed it in the sink in hot water. This place had restaurant hot water. Remember to flood and brush both sides of the board. Then dry it with a hair dryer. Dry both sides, that gets the trapped water out of your SMDs.

Repeat. I shit you not. And after that inspect and make sure you see no wet spots after the board is supposedly dry. That might be the remains of the chemical.

That's how I used to do it. It worked.


Years ago RCA sent a bulletin about the glycol leakage in the 195 series. They recommended an ammonia detergent. I used to buy tons of Parson's Sudsy Ammonia and mix it about 25-75 detergent to water. Remove anything that could trap liquid such as the flyback, smps transformer, cored inductors, etc. and give them a long hot bath in the brew. Rinse several times and put the board in the hot box for several hours. The boards looked like new and all problems caused by stray conductance disappeared. Not sure how the sudsy ammonia detergent works with electrolyte leakage but for the coolant leaks it was the bomb.

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