03-29-2010, 04:20 PM
This is my first post after searching other posts for answers and came to a wall in my 40-180 restore. A short history of events:
I salvaged it from the landfill in 1960 and it worked very good, yes I was 9 years old. Not used in the last 10 years but always in the house. Moved it to the family retreat and decided it was time to get it working on weekends. At this point lots of humming and one faint station received. Took the chassis to an Amp shop to test the tubes and he replaced the two e-caps and gave me spare tubes ($200 ouch). Still the same hum so I started studying what needed to be done and replaced all paper caps (and the e-caps with the correct value) and most resistors myself. Now no hum, no anything so I tested voltages and all tested good until I got to RF 1232/7G7 and they were very low so I stopped for that weekend thinking it would be easy to track down an error I may have made next trip. Came back this next weekend and the voltages are way off everywhere.
So what could have gone wrong while just sitting and where do I start now? I have linked a picture of the chassis upside down behind the console where it is plugged into the field coil and also a marked up diagram of the voltages from the last trip. Circled part numbers have been replaced or different values noted.
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I salvaged it from the landfill in 1960 and it worked very good, yes I was 9 years old. Not used in the last 10 years but always in the house. Moved it to the family retreat and decided it was time to get it working on weekends. At this point lots of humming and one faint station received. Took the chassis to an Amp shop to test the tubes and he replaced the two e-caps and gave me spare tubes ($200 ouch). Still the same hum so I started studying what needed to be done and replaced all paper caps (and the e-caps with the correct value) and most resistors myself. Now no hum, no anything so I tested voltages and all tested good until I got to RF 1232/7G7 and they were very low so I stopped for that weekend thinking it would be easy to track down an error I may have made next trip. Came back this next weekend and the voltages are way off everywhere.
So what could have gone wrong while just sitting and where do I start now? I have linked a picture of the chassis upside down behind the console where it is plugged into the field coil and also a marked up diagram of the voltages from the last trip. Circled part numbers have been replaced or different values noted.
<!-- m --><a class="postlink" href="http://farm5.static.flickr.com/4017/4473835437_82c1eea555_b.jpg">http://farm5.static.flickr.com/4017/447 ... a555_b.jpg</a><!-- m -->
<!-- m --><a class="postlink" href="http://farm5.static.flickr.com/4049/4473836183_e32584d724_b.jpg">http://farm5.static.flickr.com/4049/447 ... d724_b.jpg</a><!-- m -->
