05-12-2010, 02:09 PM
I always replace the line-to-ground capacitors with the X1/Y2 disk capacitors I get from Just Radios. I'm pretty sure the original .01uf caps in the bakelite block in your 40-180 are regular paper capacitors sealed in tar to limit moisture penetration, so they are subject to much the same failures as all the other paper caps you replaced.
The capacitors in the bakelite blocks are easy to clean out and replace. Some people use a heat gun to soften the tar so it will pull out of the bakelite easily in one piece. I've never tried this, but I'm told it works well. I just use the blade of a flat screwdriver and start wiggling it until the tar breaks up and comes out in pieces. It seldom takes more than a minute. This tears up the capacitors, too, so everything comes out with the tar. The remnants of the capacitor leads can just be desoldered or pulled loose.
The screwdriver technique doesn't damage the bakelite. But whatever you do, don't clamp the bakelite in a vise while you remove the tar. No matter how careful you are, you run the risk of cracking the bakelite. Don't ask me how I know this. Some people say to use mineral spirits or lacquer thinner to clean the remnants of the tar from the inside, but if any of the solvent goes astray you will clean the part number stamping off the side of the bakelite block. I just wipe the inside of the block with a rag and leave it be. The little remaining tar doesn't hurt anything.
The X1/Y2 capacitors in .01uf are very easy to wire in. They project just a millimeter or so below the edge of the bakelite block, but you can't see it when it is installed. I don't know how big the .01uf Y2 caps are, since I've never bought any. I bought some .047 Y2s once, and they were huge, way too big to fit two of them in the bakelite block.
I doubt that replacing the line capacitors will make a difference in the inverter noise you hear, sorry to say, but they should be replaced to avoid the possibility of failure down the line. Sorry, but I can't say whether adding an X cap across the line would have any effect.
The capacitors in the bakelite blocks are easy to clean out and replace. Some people use a heat gun to soften the tar so it will pull out of the bakelite easily in one piece. I've never tried this, but I'm told it works well. I just use the blade of a flat screwdriver and start wiggling it until the tar breaks up and comes out in pieces. It seldom takes more than a minute. This tears up the capacitors, too, so everything comes out with the tar. The remnants of the capacitor leads can just be desoldered or pulled loose.
The screwdriver technique doesn't damage the bakelite. But whatever you do, don't clamp the bakelite in a vise while you remove the tar. No matter how careful you are, you run the risk of cracking the bakelite. Don't ask me how I know this. Some people say to use mineral spirits or lacquer thinner to clean the remnants of the tar from the inside, but if any of the solvent goes astray you will clean the part number stamping off the side of the bakelite block. I just wipe the inside of the block with a rag and leave it be. The little remaining tar doesn't hurt anything.
The X1/Y2 capacitors in .01uf are very easy to wire in. They project just a millimeter or so below the edge of the bakelite block, but you can't see it when it is installed. I don't know how big the .01uf Y2 caps are, since I've never bought any. I bought some .047 Y2s once, and they were huge, way too big to fit two of them in the bakelite block.
I doubt that replacing the line capacitors will make a difference in the inverter noise you hear, sorry to say, but they should be replaced to avoid the possibility of failure down the line. Sorry, but I can't say whether adding an X cap across the line would have any effect.
John Honeycutt
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