I'm new to this so I need some help.I've got a SONORA RMR219 and I want to get it working I've got a diagram and I think I understand the basics of it but don't know where to start.The radio powers up and hums,the phonograph runs but the volume,tone and selector switches don't seem to do anything.I tried turning it to phonograph and playing it but just a hum,same thing when I turn it to radio and try to tune it.I just don't know if I start with the capacitors or if I should look somewhere else.I would like to learn how to do this so any information would be great.
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- Number of posts : 4
Registration date : 2011-03-21
Welcome to the forum, Fibber. I'd start by replaceing the filter caps. ..... Gregg
- Number of posts : 95
Age : 79
Registration date : 2008-05-20
What I use to do years ago was to usually change all the caps that were wax,electrolytic and test all tubes. I then use a variable voltage supply to gradually get it to 120 to test. Most of the time,90% that took care of the issue. Then if it wouldn't work I would work on it from back to front. In other words test the audio amp to the speaker first then work my way to the antenna in. I use to do this 20 years ago and I think the pattern would still work.
- Number of posts : 1391
Registration date : 2011-07-02
I used to have a signal injector pen that worked really great for locating which stage of a dead radio was causing the reception to disappear. It had a ground lead with an alligater clip on the end, and you clipped it to the chassis. The tip of the pen was then touched to each tube grid pin under the chassis (use an online tube manual such as Sylvania to identify the grids). It had an RF and also an AF multivibrator circuit in it, battery powered, and I could hear its tone in the radio speaker clearly if that stage was working. I worked backwards from the output tube towards the "front end" of the radio, the oscillator-mixer tube (again, a tube manual will give tube functions) until the signal stopped or dropped off until it could barely be heard. Then testing or substituting that tube, cleaning the tube socket contacts and the tube's base pins, and checking or replacing the capacitors and resistors in that tube's circuit usually eliminated the trouble, unless an audio transformer or antenna coupler or I.F. transformer winding is open. You can do the same thing with RF and AF signal generators, but at a lot higher cost, and have to set the generator frequency correctly to hear its signal. I also remember an old-time radio repairman who said that using a ground lead with a clip, and connecting it to the chassis, with the other end soldered to one side of a 10K one or two watt resistor, then using the resistor's free wire lead to touch each tube grid, would produce a click if the stage was working, but I had better equipment and never tried it out. Be careful of the B-plus voltages under the chassis.
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Registration date : 2013-10-17
This post is over two years old. I need to read better.
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Registration date : 2011-09-19
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