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Ok tried alignment.. Much better.. But noticed the Low end of band is very deaf..from about 600-900 Khz.. It is working since I can inject a signal from SG But levels is very high in order of -20 Dbm..Also noticed that if I put my finger on the RF tube it helps a lot.. Same thing on SW band Signal from Generator can hear but takes a higher signal..
Maybe weak RF tube? The Antenna coil checked out OK.. Not open..
Any clues??
Skip
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Quote Chas "What happen during the rewind of the Grunow was the removal of a cellulose acetate primary/secondary liner and replaced with thin plastic film. It was that liner than caused corrosion to the primary, the bottom layer.
I do not advocate placing an entire Philco chassis into an oven because a chassis may have coils wound with the cellulose plastic liner. Cellulose acetate is very flammable, that could be a disaster!"
Chas;
You have the right thought except for one detail, cellulose acetate is NOT the volatile and flammable form of celluloid, it's it's much more dangerous cousin cellulose nitrate. Cellulose nitrate is the main ingredient in gun cotton, and was also used in the production of early motion picture film, which is chemically unstable like many other volatile substances. It was also used to make artificial silk, eyeglass frames, and billiard balls, until the dangers became obvious, such as two nitrate based billiard balls slamming together and exploding in flames. Cellulose is reacted with nitric acid in one, and acetic acid in the other, the nitric acid process isn't used in any cellulose based products anymore, except for some ping pong balls made in China, everything else, photographic film, acetate sheets, and rayon are made with the acetic acid process now, it is not volatile and does not go gummy and leach corrosive byproducts, nor explode into flames, though it will still burn if held to a flame.
Regards
Arran
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Arran, I have NO clue what you are talking about... Wrong thread?
Skip
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Arran is referring to
Post #3 in this thread.
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Ok Didn't look back far enough.. Sorry about that..
Skip...
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Ok Everything was working fine..But now the OSC died.. I tried numerous 36 tubes all do not work now.. Even the one that did doesn't Oscillate now.. I was subbing tubes to see if I could get the low end of band to work better..
I hope Osc coil didn't open? I will check that tomorrow.. Then if OK.. Then Now what???
Skip
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Ok.. So radio did not Oscillate.. I put the original tubes back in and radio started to work again..Then on to my Volume problem
I checked the Volume control and all the parts that connected to it..All were OK.. But this is what I found Resistor 24 a 51K had came loose on one side Not a great solder job by me.. I re-soldered the resistor and Guess what The Volume works.. All the way up.. Also the Radio now receives the lower end of band great..
Lesson: Make sure I solder correctly and check connections after soldering..
I will do alignment over again just to make sure..
But seems all is well now..
Skip
(This post was last modified: 10-22-2018, 08:20 PM by
vecher.)
