The 155 pf cap is used to filter off the RF off the Audio, and does not need to be inside the IF can. Put it between the IF can and the 47K resistor to RF ground. A good check to see if you have SMD, is to measure the agc voltage. It should be a negative voltage. If it is positive DC voltage here, even a tenth of a volt, you have SMD. No other way to get a positive voltage here. The B+ voltage leaks through the decomposing Mica to the AGC Line. de WB5KSM
That is correct! I just learned this through the process of elimination on an RCA 3-X-533. Right after the recap and resistor replacement, it played perfectly for about a day or two before going completely dead. I found I was getting almost +3V on the AGC line. I ran across a work-around on a radio forum that uses a coupling cap, resistor and some rewiring to disable a section of the first IF can. I got lucky and it works beautifully, for now at least. The second IF seemed ok so I left it alone. I thought the selectivity would suffer, but I didn't notice any great loss. Maybe not a perfect fix, but it did give the radio some extra life. Any thoughts on this?
Good work; about that tiny wire on the coil. I learned you can use a soldering iron, pressing it into an asperin tablet. then unwrap a turn from the coil to reach, and it will solder well to its connection
I have read about this problem (SMD) with the IF cans in older radios. Luckily they had the capacitance values of those caps in side the IF cans, many times the schematics only show the capacitor symbol and no indicated value. That idea of putting the caps inside the IF cans was an engineering fail. But I guess they weren't worried about the capacitors failing 40 or 50 years down the road back then.road Thanks for the video, it seems very touch & go messing with IF cans due to their delicate nature.
I saw another youtube video where the guy opened the bottom of the if can by snipping off the top of the brass rivet with a sharp diagonal plier and then simply pulling the rivet down and out the bottom. I tried this method myself and it seems to work great.
I never had that problem before, but now I know what to do... I would search for it on eBay and other venues when the time comes...GREAT VIDEO!! Thanks for sharing your knowledge! 73, Joe-k4jga
Finally it seems that this radio just receives AM stations in the middle of the dia, this is a typical fail and hard to solve due to the IF transformers.
What was the value of the replacement capicitor for the I f cans ,I wanted to stock a few kids caps to keep around ,and they are pricey ,so if after a while.I can figure a few sizes to keep in stock..
Those IF cans were junk! I have a box of those NOS, and some of those went bad just sitting in the box for so many years before they even made it to a radio! Good job!
Are their any new old stock for the IF cans,I always wonder if tarn x silver cleaner,would remove the tarnish of of those smd IF cans ?,thanks for showing us this ,I just got a 1953 silvertone radio ,but the IF cans you worked on never seen any videos of any like those,I hope you will do a step by step of fixing some of the other kind of IT can repair.
Esses transformadores de F.I. são a parte mais chata de se reparar....a maioria na época eram muito mal construidos....os melhores eram da LUMOR.....mais um bom trabalho......
The 155 pf cap is used to filter off the RF off the Audio, and does not need to be inside the IF can. Put it between the IF can and the 47K resistor to RF ground. A good check to see if you have SMD, is to measure the agc voltage. It should be a negative voltage. If it is positive DC voltage here, even a tenth of a volt, you have SMD. No other way to get a positive voltage here. The B+ voltage leaks through the decomposing Mica to the AGC Line. de WB5KSM
That is correct! I just learned this through the process of elimination on an RCA 3-X-533. Right after the recap and resistor replacement, it played perfectly for about a day or two before going completely dead. I found I was getting almost +3V on the AGC line. I ran across a work-around on a radio forum that uses a coupling cap, resistor and some rewiring to disable a section of the first IF can. I got lucky and it works beautifully, for now at least. The second IF seemed ok so I left it alone. I thought the selectivity would suffer, but I didn't notice any great loss. Maybe not a perfect fix, but it did give the radio some extra life. Any thoughts on this?
I like your tip for looking for a positive voltage on the AVC bus to detect SMD Melvin.
Good work; about that tiny wire on the coil. I learned you can use a soldering iron, pressing it into an asperin tablet. then unwrap a turn from the coil to reach, and it will solder well to its connection
Instructive video. The IF cans are pretty formidable.
I have read about this problem (SMD) with the IF cans in older radios. Luckily they had the capacitance values of those caps in side the IF cans, many times the schematics only show the capacitor symbol and no indicated value. That idea of putting the caps inside the IF cans was an engineering fail. But I guess they weren't worried about the capacitors failing 40 or 50 years down the road back then.road Thanks for the video, it seems very touch & go messing with IF cans due to their delicate nature.
I saw another youtube video where the guy opened the bottom of the if can by snipping off the top of the brass rivet with a sharp diagonal plier and then simply pulling the rivet down and out the bottom. I tried this method myself and it seems to work great.
Learned something new here, thanks!
Fortunately I came across you, so I have a model s53a and I have a s38 hallicrafters both of which are in
Hello, what value of capacitor did you use for the 1st IF can?
I never had that problem before, but now I know what to do... I would search for it on eBay and other venues when the time comes...GREAT VIDEO!! Thanks for sharing your knowledge! 73, Joe-k4jga
Thanks For watching Joe 73's Jason
Finally it seems that this radio just receives AM stations in the middle of the dia, this is a typical fail and hard to solve due to the IF transformers.
I just stuck my soldering iron in the middle of that rivet, and pushed until the whole mica assembly fell out.
What was the value of the replacement capicitor for the I f cans ,I wanted to stock a few kids caps to keep around ,and they are pricey ,so if after a while.I can figure a few sizes to keep in stock..
I need to repair the SMD on my Zenith K725 and my GE 408
Those IF cans were junk! I have a box of those NOS, and some of those went bad just sitting in the box for so many years before they even made it to a radio! Good job!
Oh yeah that radio was a total pain!
Is there a .021 capacitor in them kind of radios
I sure do miss Retro Chad...
Whatever happened to him?
Chad retired, umajunkcollector was in contact with him.
Is this common in 30s, 40,s 50s radios? Or is it specific to a certain decade?
How many watts do these old radios use
how do I contact you about repairing a radio?
Fortunately for me I found you
Are their any new old stock for the IF cans,I always wonder if tarn x silver cleaner,would remove the tarnish of of those smd IF cans ?,thanks for showing us this ,I just got a 1953 silvertone radio ,but the IF cans you worked on never seen any videos of any like those,I hope you will do a step by step of fixing some of the other kind of IT can repair.
It's the silver that has deteriorated, might work if there is enough silver left but you still have the work of dismantling them.
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Are their replacements for it cans a modern upgrade,or is the way you are doing it the only option,
There are no modern replacements. This technology became obsolete decades ago.
Sorry to hear that the post office destroyed it
Esses transformadores de F.I. são a parte mais chata de se reparar....a maioria na época eram muito mal construidos....os melhores eram da LUMOR.....mais um bom trabalho......
Good vare good
the station with that hum just sounds like a Dalek
That sounds awesome. I’d love to sample that