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38-62 power transformer question
#4

Just looked over at nostalgiaair for the Riders schematic for the 38-62. Didn't find it there. However, I have rebuilt a few 38-62s over the years. Common Philco set with common probs. I call them boat motors because most have motorboating issues as well. If you have re-capped it, did you rebuild or sub for the orig bakelight block condensers also? If so, make sure you have tube shields on the RF tubes in the radio that require them. Sometimes the original tube shields are missing. The bases of the tubes will show if shields are missing. If the shields are missing, you can make some by cutting the top and bottom out of aluminum coke cans or similar. Cut the aluminum down the side,cut and fit height up to grid connection height on top of tube,and wrap the tubes with aluminum and tape the homemade shields around all tubes missing original tube shields . Those tube shields need to be in place because the grid connections are on top of the tubes. These particular Philco sets are as touchy as a old maid at a stag convention for eliminating random interferences. Also, other nearby household appliances such as florescent lighting fixture transformers, clothes washers, dryers, or ac line noise affect these type sets as well. Go back over your schematic and make sure you haven't missed anything. Sometimes, someone else previously possibly removed bypass caps and didn't replace all them.Having tube shields in place is critical in these sets, then look for cap bypass probs in the RF sections, and avc line as well if all else fails.


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Re: 38-62 power transformer question - by Texasrocker - 07-01-2011, 08:49 PM



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