[Bruce C]

This is an update of my progress. I brought the chassis down off the hill to work on it during the week which I have done several times. This means I cannot power test my work until I plug it back into the speaker back up on the hill. I tested the mica caps by de-soldering one end and leaving them in place and only failed one for being out of range. The power at the retreat got me thinking and doing some research. The radio has only been powered up at the family retreat since repair, which is 100% solar/battery/inverter (full sine wave) and on top of that every light is a CFL. This along with being in a weak signal location is very problematic. I will bring the cabinet down to civilization for the remainder of test and repair this weekend.

[Bruce C]

After testing the radio on clean city power I can report the inverter power I was previously using was my final problem after recapping. The radio sounds great now with good reception. Now I will put my newly acquired signal generator to use and get a better under standing of how it works while checking the alignment. The only other question I would throw out is if there is any way to eliminate the interference from the inverter and the CFL lighting. Some sites recommend twisting wires and adding ferrite filters. Except for the solar panels you wouldn'd know this house was any different than a city house with all normal 120VAC code wiring off of a distribution panel. I wonder if this a problem for the new homes with grid-tie inverter systems.

[Ron Ramirez]

Hi

I would suspect your inverter first as the source of interference.

I converted my house 100% to CFL bulbs a few years ago, and had no problems whatsoever with them.

The house where I now live has been converted to about 90% CFL bulbs, and again, no radio interference at all.

[denver]

This happend to me . Voltages checked in specs . Then a few days later they were way high got my exspensive meter out of the cold truck.
Had a cheaper craftsman in the house warm all the voltages checked good . Cold weak batteries in the other meter read high voltage.
Had me puzzled for awhile. Put new batteries in worked fine .

[Bruce C]

The inverter power was the culprit. With that resolved all I needed to do was an accurate alignment. The I.F. was simple but when it came to the R.F. I could not satisfy all five operations. Compensators 21A and 19A had very positive response but all the others had very little. The overall scale was compressed to where I could not satisfy both high and low frequency to match the index so went more for the middle. The overall performance is great except when it was on the same circuit as the bedroom dimmer switch. The only thing left to do is restore the cabinet when I retire and maybe find another one to work on.

[exray]

I don't know of any good cures for inverter noise. I think its the nature of the beast because of the switching harmonics that occur in the DC>AC conversion. There are such things as line filters that may help but if the unit is not a clean sine-wave inverter (the $$$ ones) then they might not be very effective. Sine wave and clean sine wave are two different animals. There can be all sorts of harmonic garbage along with the 60Hz sine wave.

As for CFLs, I've never had any noise problems with them but I hear people mention it occasionally. I need to interject a war story here. I had a lamp that generated a bunch of hash when using a CFL. It wasn't the fault of the CFL itself. It was fine in a different fixture. And this lamp was fine with an incandescent bulb. It turned out that the contacts in the lamp socket/switch were not so good and after a good cleaning the CFL works fine and creates no noise. I think CFLs sometimes take the brunt of blame in situations like this.

Onward to dimmers. They have a history of being noise makers. They actually sell good ones nowadays with decent filtering but they cost a bit more. I hear $25-50 range mentioned. If a guy is going to mess with radios its probably a good investment to look into the better quality dimmers.

[Bruce C]

I hate to think I will never be able to use my new hobby at my retirement home with inverter power. The SW5548 inverters were the most advanced Xantrex offered in 2005. I purchased an "Audio/Visual" line filter (48dB) at the big electronics store and it had no effect against the dimmer noise. I just got a 38-15 on Ebay so when I was ordering caps on JustRadios I read the Safety cap section. I previously checked the bakelite line caps on the 40-180 and they measured OK.

1. Should I replace them with new Y2 Safety caps anyway?
2. Would it help to add an X2 cap across the lines and what value?
3. Would a comercial power line filter like this help? Lots on Ebay.

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[codefox1]

Have you tried using an isolation transformer?

[Raleigh]

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.

[Bruce C]

I do not have an isolation transformer or variac yet, not in the budget. I would imagine not all isolation transformers are the same and in the simpliest form my not filter but just isolate. Just using a dim light tester and meter for now, which reminds me I have a Kill a Watt meter at the cabin that would show me the load also when using the dim light tester.

The Y2 caps are very large and didn’t put them in for that reason so I will get some X1/Y2 caps.

Thanks for your replys.

[Bruce C]

I do not have an isolation transformer or variac yet, not in the budget. I would imagine not all isolation transformers are the same and in the simpliest form my not filter but just isolate. Just using a dim light tester and meter for now, which reminds me I have a Kill a Watt meter at the cabin that would show me the load also when using the dim light tester.

The Y2 caps are very large and didn’t put them in for that reason so I will get some X1/Y2 caps.

Thanks for your replys.

[Bruce C]

I do not have an isolation transformer or variac yet, not in the budget. I would imagine not all isolation transformers are the same and in the simpliest form my not filter but just isolate. Just using a dim bulb tester and meter for now, which reminds me I have a Kill a Watt meter at the cabin that would show me the load also when using the DBT.

The Y2 caps are very large and didn’t put them in for that reason so I will get some X1/Y2 caps.

Thanks for your replys.