Last Winter I repaired a D board in a 32 inch Sony set. I replaced the two chips with DB versions and the set worked fine for 3 months. It eventually came back for an intermittent start up problem. It seems that at times it would just not power up with blink codes alternating between sometimes being 6 and at other times being 7. The most frustrating thing is it would sometimes go for days or weeks with no problem. I posted this a few weeks ago and received some additional information about an electrolytic capacitor which also should have been replaced at the time the chips were and I subsequently did that. After about two weeks of no problems I returned the set. It is now back again for the same intermittent start up problem. This time though I noticed something new. There are several components on the board I worked on whose leads show signs of electrolysis, as though they were wet when this set was powered up. I recalled that the first time the customer picked the set up it was raining moderately. We covered the set and I always caution them that if they even remotely suspect that a drop of water could possibly have gotten inside to not power up the set for a few days until it dries out. Whether or not they ever heed this advice is always suspect especially in this case. I'm reasonably sure that if there had been corrosion on that D board originally I would have certainly noticed it. So my question is: is it possible for corrosion to work its way into a hermetically sealed component such as a semiconductor and mess with the substrate to the point where the component becomes unreliable and circuit parameters change? The corrosion is really not that bad to the point where it is "hairy" green growing between the leads however it looks blackened and dark green and it has traveled up the leads of the affected components right up to onto into the body of the device. The board itself is fine. Any input on this would be most sincerely appreciated. Lenny.
- posted
13 years ago