EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: SPRX on August 22, 2013, 01:39:51 pm
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I have a circuit board with bogged and leaked capacitors, and when I found, it already spoiled the circuits components around. Pictured is just one location, but it had 9x caps, all had the same amount of damage to the surroundings components. What ever leaked out from the caps looks corrosive, hard and deposited salty like-thing over the adjacent pins and solder points.
This board is the Front Panel Board of my Tektronix TDS460 oscilloscope, and the issue presented with v.scale not working.
I tried this: http://www.jaycar.com.au/productView.asp?ID=NA1004 (http://www.jaycar.com.au/productView.asp?ID=NA1004) with no success.
How should I remove and clean this safely, or what chemicals should I use
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Just use dishwashing detergent, a small fiber or plastic scrub brush or a toothbrush and rinse with water. Dry with a hair dryer. Polish copper and connector surfaces with a large rubber correction eraser.
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The chip shown above is SOIC about 150mil, and with other components mostly 1206 SMDs.
I am little scared to put water into it as it has a mechanical rotary switches with some lubricant etc, which seems not water proof
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Are those black spots corroded? Have you checked them for continuity? I would start by removing the components and applying new flux with a generous amount of flux, then brush the board with some solvent (IPA or Acetone).
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The water will evaporate, after using soap, rinse thoroughly with boiled water or de-ionized water, it will not harm the switches, just dry with a hair dryer. I have done this many times without a problem damaging components. Don't saturate the board or immerse it in a tank, just scrub the contaminated areas carefully with a stiff toothbrush.
The original manufacturer probably used water-soluble flux and cleaned the circuit the same way using de-ionized water.
If the switches are not contaminated, then don't put any soap or water on them.
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Wash with water and soap rinse with clean water and then rinse with alcohol which will mix with any remaining water and cause more rapid drying, leave in a warm place such as on top of a hot water cylinder or in an airing cupboard over night.
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I agree with the previous posts. I do the following:
1. Thoroughly soak the affected areas with IPA.
2. Scrub areas with a toothbrush or antistatic brush.
3. Rinse board under warm water flow and continue to scrub around affected areas to agitate any stubborn debris/corrosion.
4. Apply IPA again and allow to dry or use a hair dryer to speed up the process.
5. Carefully inspect the affected areas with high magnification and rework any suspect areas.
6. Clean reworked areas with IPA.
Be warned that the electrolyte has a habit of collecting under IC's and it can be very hard to remove it all without first de-soldering the chip. You also need to be on the look-out for pins that have been basically turned to rust and so no longer operational. There can also be vey fine open circuits in the copper pcb tracks where the solder mask was imperfect or porous.