It is so important to have a schematic diagram! Looking at it first and studying it you can see how the components relate to each other like that long insulated bar, which isn't very commonly used in radios of this nature. Thanks for opening our lying eyes to this kind of circuit Rick! 👀 It 's so obvious now about the electrolytic capacitors being put in backwards . Thanks for sharing your knowledge! Steve
thanks for this video. trying to learn how you went about diagnosis of the condition. with the reverse polarity of the caps, this created a high resistance i assume. so would not the high resistance create low current as opposed to high current? when radio was turned on slowly,did some components heat up or where there other symptoms? thanks john
When a electrolytic capacitor is installed backwards, or reverse polarity, it's resistance is very low. The electrolytic capacitors can get so hot that they may even explode.
I’m surprised those filter caps didn’t explode. That happened to me with a solid state Magnavox record player with a point to point chassis. Little did I knew is that the polarity is backwards on that unit. I forget the term for that.
I found a diagram that had a wire shorting out the power supply. The wire weaved up and down and around the radio, but it was a dead short. I wish I could remember what radio that was, would like to show it on RUclips. Thanks for your comment.
Very interesting troubleshooting! Another issue I could see is, that as in so many American radios, there are still many carbon resistors, both old ones and new replaced ones in the chassis. Now carbon resistors are not recommendable in any audio circuits, as they cause lots of hiss, they also are a real problem as they change their value quite quickly, the higher the working voltage is! The modern carbon resistors do have the beige body colour. This means, that the working voltage in the circuit can float around with carbon resistors. In antenna circuits they sometimes can also be a damping for rf signals. To overcome this problem, I highly recommend to replace all the 10% carbon resistors by modern 1% metal film resistors, if they are below 1 Watt. The metal film resistors can be identified, as they have a blueish body colour. If their rating should be above 1W, metal oxide resistors or wire resistors are the very best solution. When a tube or transistor circuit is equipped with metal film resistors, the circuit will run with very precise voltage tolerances, and the RF circuit part like the oscillator can work with more accuracy or in other words, more frequence stability. The AF amplifier stage is improved by less hiss and precise amplification level at each point in the circuit. The reason, RF wire coils like IF tanks can be open is mostly to thin copper wire material which has a isolation material which is not acid free, causing verdigris in the thin copper wires over the decades, especially if a chassis has been exposed to humidity over a period of time. Another point to take care off is, that in many American radio chassis, there are ceramic capacitors used in the AF amplifier stage. In the RF stage, ceramic or mica capacitors can do a good job, especially the oscillator cap is a good choice to use a ceramic or mica cap, as ceramic caps cause little frequency deviation. But when using ceramic or mica caps in the AF amplifier stage, this can cause a bit of a squeaky telephone alike sound in the speaker. It's better to put metal film capacitors in the AF amplifier stage, this helps to improve the sound quality, as metal film capacitors do have better frequency specifications when used with low audible AF-frequency signals, than ceramic or mica capacitors do have. Best regards from Switzerland, bluearcturus
@@majortom5838 Of course, you're right, these AA5 sets are very sturdy, no question. The small output transformer does not allow frequencies to pass under maybe 80 Hertz or so, but this is wanted, to avoid 50/60 Hertz line-hum problems from the rectifier stage, to not use too large filter capacitors . But, und here's the important thing of my commentary: ceramic capacitors can cause issues under some circumstances. Ceramic capacitors are very good in RF stages, but one must always be aware, that they are very frequency dependant and also voltage dependant. To illustrate what I mean, watch this video: ruclips.net/video/Kn-8hvvz9Ag/видео.html Here's a TV restorer showing the problems he has with a Philco safari TV. He has replaced old caps with ceramic caps, and now he's troubled to get the test images on the screen right. He's showing the distortion, ceramic caps can cause on the screen of the oscilloscope. He replaces the ceramic caps again by unpolarized film caps, and the problems are gone. This is what I mean, that ceramic caps (don't must but) can be problematic in AF amplifier stages. For Hifi amplifiers, ceramics caps are a no go, but for instrumental amps like guitar amps or Hammond organ amps, where a specific "sound colouration" is wanted, they are the right choice. Trial and error. Hope my comment is of interest, have fun and best regards! bluearcturus
@H Higgins Very clever to tap on components, to make sure the is no microphonism or sometimes unwanted hidden issues like unvisible hairline cracks or bad soldering points. Very important is always to measure the isolation resistance of the capacitor. I use the Hewlett-Packard 4329A high resistance meter, the well known Heathkit IT-11 capacitor checker is also very recommendable. A test voltage of about 100Volts DC is needed, to show problems with isolation resistance. Capacitors can have hairline cracks in their outer surrounding and so humidity can enter the body of the capacitor, causing the DC-isolation resistance of the capacitor goes down. A healthy capacitor has a infinite DC isolation resistance. If this is the case, the DC coupling in circuits is no longer ok. If a leaky cap is in a circuit there can be some DC voltage at a point where no DC voltage should be, and at another point, there is no longer the wanted amount of DC voltage, because the leaky cap is shorting some DC voltage out to other points, where no DC voltage should be. Early caps from the 1930's to 50's sometimes have bodies built from cartoon tubes, and the isolation material is wax. Now both cartoon and wax are hygroscopic materials, they take up humidity from the surrounding, and this is making the cap leaky. Modern metal film caps are completely plastic welded, there is no longer the problem, that humidity can enter the body of the capacitor, avoiding problems for future decades. The old American "chocolate piece" brown rectangular mica caps are very good, most of them are still ok after such a long time. Have fun and best regards, bluearcturus
I've been waiting 10 years for this video!
Good job 😄
Thanks
Showing the difference between grounds and the importance it makes to the front end is great! I wish more people would talk about it.
Thanks and your welcome.
Glad your back! and a radio video to boot! Stay well.
Thanks
It is so important to have a schematic diagram! Looking at it first and studying it you can see how the components relate to each other like that long insulated
bar, which isn't very commonly used in radios of this nature. Thanks for opening our lying eyes to this kind of circuit Rick! 👀 It 's so obvious now about the
electrolytic capacitors being put in backwards . Thanks for sharing your knowledge! Steve
Thanks, and your welcome.
Thanks for your comment.
What a discovery Rick. Great detective work on this circuit.
Thanks Carl. Merry Christmas and Happy New Year.
Great informational video. Thank you very much! Have a good day!
THANK YOU!
thanks for this video.
trying to learn how you went about diagnosis of the condition.
with the reverse polarity of the caps, this created a high resistance i assume.
so would not the high resistance create low current as opposed to high current?
when radio was turned on slowly,did some components heat up or where there other symptoms?
thanks
john
When a electrolytic capacitor is installed backwards, or reverse polarity, it's resistance is very low. The electrolytic capacitors can get so hot that they may even explode.
@@AllAmericanFiveRadio thanks now i see why current would be high as you stated.
john
Oh we’ve all done this a time or two!
Been there done that too.
I’m surprised those filter caps didn’t explode. That happened to me with a solid state Magnavox record player with a point to point chassis. Little did I knew is that the polarity is backwards on that unit. I forget the term for that.
Thanks and your welcome.
Nice tips! Thanks.
Thanks, and your welcome.
Before your friend replaced the main smoothing caps, something blew up ---. There is a great big sooty stain on the underside of the chassis....
Glad it did not damage the wafer board.
Great! Another video from AllASMRradio!
Thanks and your welcome.
So the backwards capacitors blew out the tube and the coils?
I think the coils where already open. The capacitors in backwards will short out the B+ burning out the 35W4 rectifier tube.
Thanks for your comment.
Interesting.
I once encountered a TV where the polarity of an electrolytic capacitor in the diagram was opposite to a factory marking on the PCB.
I found a diagram that had a wire shorting out the power supply. The wire weaved up and down and around the radio, but it was a dead short. I wish I could remember what radio that was, would like to show it on RUclips.
Thanks for your comment.
Happy belated new year! Hope all is well!
Thanks
So far so Good.
One problem not related to the power issue is that the leads are way too long to be bare.
Liquid Tape
@@AllAmericanFiveRadio I suppose that's one way. :)
What did the customer decide to do?
I'm going to try and repair the I.F.s
Very interesting troubleshooting! Another issue I could see is, that as in so many American radios, there are still many carbon resistors, both old ones and new replaced ones in the chassis. Now carbon resistors are not recommendable in any audio circuits, as they cause lots of hiss, they also are a real problem as they change their value quite quickly, the higher the working voltage is! The modern carbon resistors do have the beige body colour. This means, that the working voltage in the circuit can float around with carbon resistors. In antenna circuits they sometimes can also be a damping for rf signals. To overcome this problem, I highly recommend to replace all the 10% carbon resistors by modern 1% metal film resistors, if they are below 1 Watt. The metal film resistors can be identified, as they have a blueish body colour. If their rating should be above 1W, metal oxide resistors or wire resistors are the very best solution. When a tube or transistor circuit is equipped with metal film resistors, the circuit will run with very precise voltage tolerances, and the RF circuit part like the oscillator can work with more accuracy or in other words, more frequence stability. The AF amplifier stage is improved by less hiss and precise amplification level at each point in the circuit. The reason, RF wire coils like IF tanks can be open is mostly to thin copper wire material which has a isolation material which is not acid free, causing verdigris in the thin copper wires over the decades, especially if a chassis has been exposed to humidity over a period of time. Another point to take care off is, that in many American radio chassis, there are ceramic capacitors used in the AF amplifier stage. In the RF stage, ceramic or mica capacitors can do a good job, especially the oscillator cap is a good choice to use a ceramic or mica cap, as ceramic caps cause little frequency deviation. But when using ceramic or mica caps in the AF amplifier stage, this can cause a bit of a squeaky telephone alike sound in the speaker. It's better to put metal film capacitors in the AF amplifier stage, this helps to improve the sound quality, as metal film capacitors do have better frequency specifications when used with low audible AF-frequency signals, than ceramic or mica capacitors do have. Best regards from Switzerland, bluearcturus
@@majortom5838 Of course, you're right, these AA5 sets are very sturdy, no question. The small output transformer does not allow frequencies to pass under maybe 80 Hertz or so, but this is wanted, to avoid 50/60 Hertz line-hum problems from the rectifier stage, to not use too large filter capacitors . But, und here's the important thing of my commentary: ceramic capacitors can cause issues under some circumstances. Ceramic capacitors are very good in RF stages, but one must always be aware, that they are very frequency dependant and also voltage dependant. To illustrate what I mean, watch this video: ruclips.net/video/Kn-8hvvz9Ag/видео.html Here's a TV restorer showing the problems he has with a Philco safari TV. He has replaced old caps with ceramic caps, and now he's troubled to get the test images on the screen right. He's showing the distortion, ceramic caps can cause on the screen of the oscilloscope. He replaces the ceramic caps again by unpolarized film caps, and the problems are gone. This is what I mean, that ceramic caps (don't must but) can be problematic in AF amplifier stages. For Hifi amplifiers, ceramics caps are a no go, but for instrumental amps like guitar amps or Hammond organ amps, where a specific "sound colouration" is wanted, they are the right choice. Trial and error. Hope my comment is of interest, have fun and best regards! bluearcturus
@H Higgins Very clever to tap on components, to make sure the is no microphonism or sometimes unwanted hidden issues like unvisible hairline cracks or bad soldering points. Very important is always to measure the isolation resistance of the capacitor. I use the Hewlett-Packard 4329A high resistance meter, the well known Heathkit IT-11 capacitor checker is also very recommendable. A test voltage of about 100Volts DC is needed, to show problems with isolation resistance. Capacitors can have hairline cracks in their outer surrounding and so humidity can enter the body of the capacitor, causing the DC-isolation resistance of the capacitor goes down. A healthy capacitor has a infinite DC isolation resistance. If this is the case, the DC coupling in circuits is no longer ok. If a leaky cap is in a circuit there can be some DC voltage at a point where no DC voltage should be, and at another point, there is no longer the wanted amount of DC voltage, because the leaky cap is shorting some DC voltage out to other points, where no DC voltage should be. Early caps from the 1930's to 50's sometimes have bodies built from cartoon tubes, and the isolation material is wax. Now both cartoon and wax are hygroscopic materials, they take up humidity from the surrounding, and this is making the cap leaky. Modern metal film caps are completely plastic welded, there is no longer the problem, that humidity can enter the body of the capacitor, avoiding problems for future decades. The old American "chocolate piece" brown rectangular mica caps are very good, most of them are still ok after such a long time. Have fun and best regards, bluearcturus
Thanks for the information.
Nice editings.
Thanks
What a terrible mistake to make. Those IF cans won't be easy to replace.
Flea Market here i come.
Yikes!
Thanks
OOOOOOOPPPSSS!!!!!!!!!!!!!!!!!!!!!!!!!!!
Been there done that.