What Died in my Radio ??

[John Holotko]

I started out to fix my dad's old Zenith tube portable broadcast receiver (vintage 1940's) last night. Since I don't have the big B+ battery thyat goes into the thing I decided to test it off the ac line. (It was designed to run of battery and ac). So I plugged it in and started waiting for it to warm up.  I suddenly noticed a very foul stench and started wondering if some small animal didn't die and start rotting in the corner of the shack where my workbench is. I then noticed the stench coming from the radio and figured something must have crawled into the case and died in there. Then I saw some smoke looked where it was coming from and put two and two together when I realized that what I was smelling was good ol;' selenium dioxide gas coming from a hot selenium rectifier stack that was crapping out. The stench was incredibly putrid. I have never had a selenium  rectifier crap out on me before but I heard they do stink pretty awful when they do. Well last night I learned first hand howe bad they stink. Fortunately I pulled the plug and it cooled down before it got a change to totally stink up the whole place.  Some components smell pretty bad when they burn up but that selenium recitifier has to be the worst stench yet.

[Vortex Joe - N3IBX]

John,
      Not only do selenium rectifiers really "stink" when they go, the selenenium vapor is poisionous. I hope you didn't inhale any! The best replacement for the selenium is a diode(s) across the circut.

I'm curious what the model # of the Zenith receiver you were working on? If you need a schematic for it, I'd be glad to copy it and email it to you. I've got all 23 volumes of "Riders" Manuals, which are an incredible resource for repairing commercial sets.

Best Regards and a Happy New Year.
                                                  Joe Cro N3IBX

[John Holotko]

John,
      Not only do selenium rectifiers really "stink" when they go, the selenenium vapor is poisionous. I hope you didn't inhale any! The best replacement for the selenium is a diode(s) across the circut.

I'm curious what the model # of the Zenith receiver you were working on? If you need a schematic for it, I'd be glad to copy it and email it to you. I've got all 23 volumes of "Riders" Manuals, which are an incredible resource for repairing commercial sets.

Best Regards and a Happy New Year.
                                                  Joe Cro N3IBX

Hi Joe,

Well as soon as I saw what was happening I immediatly shut the radio down and the rectifier cooled off pretty quick so I guess it released only a minimal amount of gas. Not enough to poison me but enough to give off one nasty stink. Oh there are things that stink worst but I must admit, the odor from that rectifier was pretty rank.

Okay, with regards to the model it's a Zenith "WaveMagnet" portable. The model number is "6G801".  Yes, I could really use a schematic for it. If you happen to have a copy of it I would really appreciate if you can email me a copy.
You can reach me by email at   n2ize@nerdshack.com  .   At your conveniance of course and I am very grateful for your help.If I can ever be of any help or assistance please let me know.

Have a Happy Holiday Season and a very Happy New year.

[W3SLK]

I have to agree with Joe, those damn selenium rectifiers are the most putrid smelling devices when they go TANGO UNIFORM. I remember doing early Kirlian photography experiments in my friend's basement when one of those cut loose. His mother wanted to know what we had killed and how long did we intend on leaving it down in the basement.

[WA1GFZ]

Check the power supply caps one may be shorted taking out the rotten egg.
In my early days I took out a few.

[Vortex Joe - N3IBX]

John,
      Not only do selenium rectifiers really "stink" when they go, the selenenium vapor is poisionous. I hope you didn't inhale any! The best replacement for the selenium is a diode(s) across the circut.

I'm curious what the model # of the Zenith receiver you were working on? If you need a schematic for it, I'd be glad to copy it and email it to you. I've got all 23 volumes of "Riders" Manuals, which are an incredible resource for repairing commercial sets.

Best Regards and a Happy New Year.
                                                  Joe Cro N3IBX

Hi Joe,

Well as soon as I saw what was happening I immediatly shut the radio down and the rectifier cooled off pretty quick so I guess it released only a minimal amount of gas. Not enough to poison me but enough to give off one nasty stink. Oh there are things that stink worst but I must admit, the odor from that rectifier was pretty rank.

Okay, with regards to the model it's a Zenith "WaveMagnet" portable. The model number is "6G801".  Yes, I could really use a schematic for it. If you happen to have a copy of it I would really appreciate if you can email me a copy.
You can reach me by email at   n2ize@nerdshack.com  .   At your conveniance of course and I am very grateful for your help.If I can ever be of any help or assistance please let me know.

Have a Happy Holiday Season and a very Happy New year.

John - Your schematics are in your email. Good luck and have fun.
                                                                                        Joe Cro N3IBX

[Ed/KB1HYS]

Does that Zenith  look like a suitcase??  I picked up something that sounds similar,  from a friend of my wife. it's been sitting in the shack as it is only an commercial MW band reciever.  I guess I'll have to pull it out and take a look see now.  It has a simulated alligator hide covering and weighs about 20lbs. top cover latches shut and the thing looks just like an old suitcase or maybe a big size briefcase...
 Can't really imagine someone walking down the street with that on thier shoulder bopping to the tunes...

actually maybe I can  

[Vortex Joe - N3IBX]

Does that Zenith  look like a suitcase??  I picked up something that sounds similar,  from a friend of my wife. it's been sitting in the shack as it is only an commercial MW band reciever.  I guess I'll have to pull it out and take a look see now.  It has a simulated alligator hide covering and weighs about 20lbs. top cover latches shut and the thing looks just like an old suitcase or maybe a big size briefcase...
 Can't really imagine someone walking down the street with that on thier shoulder bopping to the tunes...

actually maybe I can  

Ed - If you need the skizmatics for it let me know. I've got the Riders' manwells on CD.
Joe N3IBX

[Pete, WA2CWA]

Ed - If you need the skizmatics for it let me know. I've got the Riders' manwells on CD.
Joe N3IBX

I had a set of those Rider CD’s several years ago. Almost every time I went to look up something, the page scan, as viewed on the screen, was only fair to poor, and even worse when I printed it on a laser printer. Finally got all the Volumes on “real paper”. Life got better.

[John Holotko]

Check the power supply caps one may be shorted taking out the rotten egg.
In my early days I took out a few.

Yeah, thats where I am going to check next. There's one of those large  multivalue  (4 caps in 1) caps in the power supply and I suspect it might be shorted bacause there's a wirewound resistor in series and that was overheating and  burning as well  as the rectifier so I suspect that  cap may be shorted.  Matter of fact I am going to recap the whole radio. There are plenty of old wax paper caps in there that I should replace..

[John Holotko]

John,
      Not only do selenium rectifiers really "stink" when they go, the selenenium vapor is poisionous. I hope you didn't inhale any! The best replacement for the selenium is a diode(s) across the circut.

I'm curious what the model # of the Zenith receiver you were working on? If you need a schematic for it, I'd be glad to copy it and email it to you. I've got all 23 volumes of "Riders" Manuals, which are an incredible resource for repairing commercial sets.

Best Regards and a Happy New Year.
                                                  Joe Cro N3IBX

Hi Joe,

Well as soon as I saw what was happening I immediatly shut the radio down and the rectifier cooled off pretty quick so I guess it released only a minimal amount of gas. Not enough to poison me but enough to give off one nasty stink. Oh there are things that stink worst but I must admit, the odor from that rectifier was pretty rank.

Okay, with regards to the model it's a Zenith "WaveMagnet" portable. The model number is "6G801".  Yes, I could really use a schematic for it. If you happen to have a copy of it I would really appreciate if you can email me a copy.
You can reach me by email at   n2ize@nerdshack.com  .   At your conveniance of course and I am very grateful for your help.If I can ever be of any help or assistance please let me know.

Have a Happy Holiday Season and a very Happy New year.

John - Your schematics are in your email. Good luck and have fun.
                                                                                        Joe Cro N3IBX

Joe, thank you very much. I found the scematics in my email and viewed them on screen. The schematic and info  provided that you sent will be very helpful in getting thatn radio up and running again. They came through just fine. Now I just have  to print up a copy so I can have the scematic handy at the bench while  I am working on the receiver.
 

[John Holotko]

Does that Zenith  look like a suitcase??  I picked up something that sounds similar,  from a friend of my wife. it's been sitting in the shack as it is only an commercial MW band reciever.  I guess I'll have to pull it out and take a look see now.  It has a simulated alligator hide covering and weighs about 20lbs. top cover latches shut and the thing looks just like an old suitcase or maybe a big size briefcase...
 Can't really imagine someone walking down the street with that on thier shoulder bopping to the tunes...

actually maybe I can  

Hmmmm... no not exactly like a suitcase and considerably smaller. It looks more like a large ladies travel case, you know the kind women used to carry cosmetics and personal effects in when they travelled. . This particular radio came out around 1948 or 49 and the case was designed to have a more "art deco" appearance to it. It is largely beige in colour and is molded out of some sort  of a plastic, most likely cellulose acetate or something similar. Instead of opening from the top like some of the older models this radio has two small spring loaded doors on the front which pop open when a small brass plated buttion on the top of the radio is pressed. The doors swing open to reveal the radios tuning dial, speaker  grille  and control knobs. The on/off switch is also hooked up to the doors in such a way that the radio switches on when the doors are popped open and  switches off when the user shuts the doors. Also when the doors are popped open the AM loop antenna (encased in a plastic enclosure) pops up via an narrow opening in thew back of  the radio.  The backl of the radio can also be pulled open by the user to reveal  the chassis and battery compartment as  well as storage space for the ac line cord and an optional  external  plug in antenna that can be sttached  to a car window via suction cups to provide for better reception when the radio was used inside of a car.

I tried to locate some pictures but couldn't  find and on line. When I put this one back together I'll post a pic of it up on my website.

ize

[Ed/KB1HYS]

Interesting, does sound a lot like the rig I have here, even that loop ant with the suction cups on it.   I pulled it off of the shelf.  Says its a General E;ectric Model 254A.   AM broadcast only, dial has Kilocycles around the top and meters around the bottom.  options for battery or AC operation.

I like the loop antenna... it's called an "Interceptor Beamascope" for use in planes, trains, hotels and automobiles.

I also picked up a Zenith floor model a couple days ago... another "project' radio that I'll try to save from the dump!!!  That's a neat one. Has a three way knob on the front, outer one selects the band (or did, its snaped off) Inner knob tuned and the innermost was the on/off volume control.  a lot of pushbuttons too.  love the old art-deco wood work and trim.