Hello all. I am recapping a Atwater Kent Model 55C radio. Be nice if I could find the caps. My guess is they are located in the 4 square containers that are full of tar. Can anyone tell me if this is so how do I keep track of all the wiring to remove these containers and then how do I get the tar out of them. Can anyone tell me what is in the round shiny metal containers? Thanks for the replies and remember I am a newbie!!!

Terry

Terry

Use Leigh's schematics. He redrew Atwater Kent schematics and includes more information.

http://www.atwaterkent.info/TechData/akDrawingIndex.html

AK55 and AK55C are the same circuit. C version doesn't have the metal cabinet as it was made to mount in a console.

Caps are sealed in a metal container. You should find a brown metal box. Remove the cover. Under it will be a second sealed metal box with the caps. They are sealed so well caps are often ok.

If you want to replace the caps might just throw away the metal box with caps. You could make up PC board with replacement caps. Then use the original brown AK cover to go over your replacements.

Norm

:Hello all. I am recapping a Atwater Kent Model 55C radio. Be nice if I could find the caps. My guess is they are located in the 4 square containers that are full of tar. Can anyone tell me if this is so how do I keep track of all the wiring to remove these containers and then how do I get the tar out of them. Can anyone tell me what is in the round shiny metal containers? Thanks for the replies and remember I am a newbie!!!
:
:Terry

Hello Norm
I made up another cap can using a pc board I
:Terry
:
: Use Leigh's schematics. He redrew Atwater Kent schematics and includes more information.
:
:http://www.atwaterkent.info/TechData/akDrawingIndex.html
:
: AK55 and AK55C are the same circuit. C version doesn't have the metal cabinet as it was made to mount in a console.
:
: Caps are sealed in a metal container. You should find a brown metal box. Remove the cover. Under it will be a second sealed metal box with the caps. They are sealed so well caps are often ok.
:
: If you want to replace the caps might just throw away the metal box with caps. You could make up PC board with replacement caps. Then use the original brown AK cover to go over your replacements.
:
:Norm
:
:
:
::Hello all. I am recapping a Atwater Kent Model 55C radio. Be nice if I could find the caps. My guess is they are located in the 4 square containers that are full of tar. Can anyone tell me if this is so how do I keep track of all the wiring to remove these containers and then how do I get the tar out of them. Can anyone tell me what is in the round shiny metal containers? Thanks for the replies and remember I am a newbie!!!
::
::Terry

Hello Norm
I made up another cap can using a pc board I still need to see if it works if it don't I will reuse the original can. I took this radio apart before knowing that the caps may be good.
Thanks for the help.
Terry
:Terry
:
: Use Leigh's schematics. He redrew Atwater Kent schematics and includes more information.
:
:http://www.atwaterkent.info/TechData/akDrawingIndex.html
:
: AK55 and AK55C are the same circuit. C version doesn't have the metal cabinet as it was made to mount in a console.
:
: Caps are sealed in a metal container. You should find a brown metal box. Remove the cover. Under it will be a second sealed metal box with the caps. They are sealed so well caps are often ok.
:
: If you want to replace the caps might just throw away the metal box with caps. You could make up PC board with replacement caps. Then use the original brown AK cover to go over your replacements.
:
:Norm
:
:
:
::Hello all. I am recapping a Atwater Kent Model 55C radio. Be nice if I could find the caps. My guess is they are located in the 4 square containers that are full of tar. Can anyone tell me if this is so how do I keep track of all the wiring to remove these containers and then how do I get the tar out of them. Can anyone tell me what is in the round shiny metal containers? Thanks for the replies and remember I am a newbie!!!
::
::Terry

Terry,
Four squarish metal cans may have audio transformers, power transformers or caps, but separately. The shiny round cans are probably electrolytic (polarized) caps. You need a good chassis assembly drawing to define all those items. A decent digital camera in macro-mode on a tripod will get good close-ups for wiring ID, or make your own drawing by color coding each wire/terminal before removal with a small dot of acrylic paint. The cans can be emptied using an oven or BBQ to soften (melt) the tar. Check other postings here on that subject. For the real newbie, I created a text document a couple years back on the same subject.

marv

:Hello all. I am recapping a Atwater Kent Model 55C radio. Be nice if I could find the caps. My guess is they are located in the 4 square containers that are full of tar. Can anyone tell me if this is so how do I keep track of all the wiring to remove these containers and then how do I get the tar out of them. Can anyone tell me what is in the round shiny metal containers? Thanks for the replies and remember I am a newbie!!!
:
:Terry

Terry: With the front of the radio facing you, the square brown containers in the back are from left to right: Power Transformer, Filter Choke Unit, Condenser Unit(where the electrolytic filter caps are), Audio Input and Output transformers. The 2 round shiney metal cans in the front are shielded RF coils. You can cut the wires off the bottom of the can to remove it. Pry the top off the can and use a hot plate to gradually warm the can to soften the tar (DO THIS OUTDOORS with plenty of ventilation since the goo can smoke). Once softened, you can pull the guts out and clean the inside. I used small terminal strips to mount the new caps. You might want to increase the values of the caps since the original design used 2 and 2.3 mfd caps. I think I used 6 or 8 mfd caps for better filtering. Pay close attention to the schematic so you keep the polarity of each cap correct. There are actually 6 caps in the can: 0.5 mfd for 1st AF filter, connected between the center stud and terminal 3; 1 mfd detector filter, connected between terminal 5 and can (ground); 0.5 mfd 1st AF bias, connected between center stud and can; Filter #1, 2.0 mfd, connected between terminals 1 & 4; Filter #2, 2.3 mfd, connected between terminals 2 & 4; Filter #3, 2.3 mfd, connected between terminals 6 and can. Also check the continuity of the audio input and output transformers since they are notoriously open. I had to replace both of mine, and found new replacements that fit nicely in the can. Hope this helps.
Steve

Hello Steve and thank you for the reply. I am new at this and only recapped two radios. I though the rule was to recap all antique radios but now I finding out maybe I don't need to recap this one. I removed the power transforming thinking there was some caps in that container but now I am thing there is not. I need to replace some of the wiring coming out of it anyway because the black thick outside insulation is breaking up and the inner insulation is not the greatest. Do you think I need to go into the power transformer container and do you think I should recap this radio? What gage wire do you think I should use and can I use single stran? I believe the filament wires are the ones that lost the insulation. Thanks for all your help.

Terry
:Terry: With the front of the radio facing you, the square brown containers in the back are from left to right: Power Transformer, Filter Choke Unit, Condenser Unit(where the electrolytic filter caps are), Audio Input and Output transformers. The 2 round shiney metal cans in the front are shielded RF coils. You can cut the wires off the bottom of the can to remove it. Pry the top off the can and use a hot plate to gradually warm the can to soften the tar (DO THIS OUTDOORS with plenty of ventilation since the goo can smoke). Once softened, you can pull the guts out and clean the inside. I used small terminal strips to mount the new caps. You might want to increase the values of the caps since the original design used 2 and 2.3 mfd caps. I think I used 6 or 8 mfd caps for better filtering. Pay close attention to the schematic so you keep the polarity of each cap correct. There are actually 6 caps in the can: 0.5 mfd for 1st AF filter, connected between the center stud and terminal 3; 1 mfd detector filter, connected between terminal 5 and can (ground); 0.5 mfd 1st AF bias, connected between center stud and can; Filter #1, 2.0 mfd, connected between terminals 1 & 4; Filter #2, 2.3 mfd, connected between terminals 2 & 4; Filter #3, 2.3 mfd, connected between terminals 6 and can. Also check the continuity of the audio input and output transformers since they are notoriously open. I had to replace both of mine, and found new replacements that fit nicely in the can. Hope this helps.
:Steve

Hi, Steve just thought I should let you know all the caps I bought which was suppose to be enough to recap this radio where non polar caps? Do you think I should contact my supplier?
Thanks again Terry.
:Terry: With the front of the radio facing you, the square brown containers in the back are from left to right: Power Transformer, Filter Choke Unit, Condenser Unit(where the electrolytic filter caps are), Audio Input and Output transformers. The 2 round shiney metal cans in the front are shielded RF coils. You can cut the wires off the bottom of the can to remove it. Pry the top off the can and use a hot plate to gradually warm the can to soften the tar (DO THIS OUTDOORS with plenty of ventilation since the goo can smoke). Once softened, you can pull the guts out and clean the inside. I used small terminal strips to mount the new caps. You might want to increase the values of the caps since the original design used 2 and 2.3 mfd caps. I think I used 6 or 8 mfd caps for better filtering. Pay close attention to the schematic so you keep the polarity of each cap correct. There are actually 6 caps in the can: 0.5 mfd for 1st AF filter, connected between the center stud and terminal 3; 1 mfd detector filter, connected between terminal 5 and can (ground); 0.5 mfd 1st AF bias, connected between center stud and can; Filter #1, 2.0 mfd, connected between terminals 1 & 4; Filter #2, 2.3 mfd, connected between terminals 2 & 4; Filter #3, 2.3 mfd, connected between terminals 6 and can. Also check the continuity of the audio input and output transformers since they are notoriously open. I had to replace both of mine, and found new replacements that fit nicely in the can. Hope this helps.
:Steve

Terry: you need electrolytic caps which have a positive and negative side for the power supply filtering. The other circuit bypass and coupling caps can use regular axial style metal/film caps with the appropriate voltage ratings. The original ratings were 150v and 400v (see the schematics on this site with the hand written notations), so I just used 600v ratings for everything there. The RF and detector bypass caps are in a metal housing and should be okay, but if found defective can be replaced with regular metal/film caps per the values on the schematics.
Steve

Hi Steve and thanks for all the help.
Are the power supply caps in the power supply housing?
Can I replace bad wiring with single stran wiring from radio shack?
Sorry to keep bothering you but the more I learn the less questions I will have. Thanks again. Terry.
:Terry: you need electrolytic caps which have a positive and negative side for the power supply filtering. The other circuit bypass and coupling caps can use regular axial style metal/film caps with the appropriate voltage ratings. The original ratings were 150v and 400v (see the schematics on this site with the hand written notations), so I just used 600v ratings for everything there. The RF and detector bypass caps are in a metal housing and should be okay, but if found defective can be replaced with regular metal/film caps per the values on the schematics.
:Steve

Terry: The power supply caps (electrolytics) are in the square brown box I indicated earlier as the "Condenser Unit" (using the jargon in the original owner's manual. With the radio facing you, it should be the third square box from the left. I wouldn't use Rad-Shack wire on a radio of that vintage. I used cloth covered wire in mine to keep the look as original as possible. You can get it from a number of sources including Radio Daze and Antique Radio Supply. It comes in a number of colors. Solid wire is often easier to work with than stranded, but I use both. Whatever you decide, just be sure to use wire that is rated for 600v and rated to 105C. What state is your radio in? Are you sure to need to replace the filter caps?
Also check the Atwater Kent website at: http://www.atwaterkentradio.com/
for more resources.

Hello Steve.
The radio is in really good shape other than a fraid power cord but being new at this I removed the cap box and the power supply. I was told you should always recap an old radio. The leads going to the filaments were brittle and broke up. I am not going to open the cap inner can that way if things don't work out I will reinstall the old can. I am going to build a new one on a circuit board the problem is the 1st a-f bias cap on the schematic shows .1mf and in the notes it shows .5mf. I got a .1mf cap. Do you think it will work? I sure thank you for all your help.
Thanks again Terry.
:Terry: The power supply caps (electrolytics) are in the square brown box I indicated earlier as the "Condenser Unit" (using the jargon in the original owner's manual. With the radio facing you, it should be the third square box from the left. I wouldn't use Rad-Shack wire on a radio of that vintage. I used cloth covered wire in mine to keep the look as original as possible. You can get it from a number of sources including Radio Daze and Antique Radio Supply. It comes in a number of colors. Solid wire is often easier to work with than stranded, but I use both. Whatever you decide, just be sure to use wire that is rated for 600v and rated to 105C. What state is your radio in? Are you sure to need to replace the filter caps?
:Also check the Atwater Kent website at: http://www.atwaterkentradio.com/
:for more resources.

I believe that the original filter capacitors were not electrolytic. If you decide to replace them, I would use electrolytics, being careful with the polarity.

But I think you should first determine if the originals are shot. There is a good chance they are OK. And, if you start digging out the tar, you will likely damage the power supply choke. If you determine that one of the filer caps is shot, you may be able to gently remove its leads from the top of the tar and haywire in a replacement e-cap, and save a lot of aggrevation.

The usual advice to automatically replace all caps doesn't apply to this set, in my opinion. The mica caps should be fine.

The values of the various bypass caps are not critical.
Doug

:Terry: The power supply caps (electrolytics) are in the square brown box I indicated earlier as the "Condenser Unit" (using the jargon in the original owner's manual.

Terry: Doug is correct. The original filter caps were not electrolytic, since electrolytics were first invented in 1928. The originals to this set were probably "paper type capacitors", but I would use electrolytics here if yours are bad. I think I used 10 mfd caps in place of my 2 and 2.3 mfd sections for better filtering. The original 2 and 2.3 mfd caps are kind of wimpy when it comes to filtering. One of the original Atwater service bulletins mentions using 10 mfd caps if customers complain about hum. As pointed out earlier the mica caps should be okay. Take your time on this project, and don't get in a hurry to see fast results. Take it one step at a time. My radio had about a dozen major faults, but I finally got it going and playing well. Even after you get it going, components may fail from being energized after more than 70 years. RF chokes are a prime failure point too on this radio. Atwater radios were Cadillacs in their day and built well. Take your time and do it right. You'll be pleased with the results in the end.
Steve

Hello Doug.
Well I guess I am going to just put this radio back together with the original capacitor box and turn her on and see what happens. I did not know there was anything else but capacitors in that tar but I did not take it apart. I built a new one on a PC board with the 6 capacitors I though were in that box did not know there was a power supply choke in there also. I will let you all know how I make out.
Thanks again. Terry.
:I believe that the original filter capacitors were not electrolytic. If you decide to replace them, I would use electrolytics, being careful with the polarity.
:
:But I think you should first determine if the originals are shot. There is a good chance they are OK. And, if you start digging out the tar, you will likely damage the power supply choke. If you determine that one of the filer caps is shot, you may be able to gently remove its leads from the top of the tar and haywire in a replacement e-cap, and save a lot of aggrevation.
:
:The usual advice to automatically replace all caps doesn't apply to this set, in my opinion. The mica caps should be fine.
:
:The values of the various bypass caps are not critical.
:Doug
:
::Terry: The power supply caps (electrolytics) are in the square brown box I indicated earlier as the "Condenser Unit" (using the jargon in the original owner's manual.

Terry: The filter chokes are in the second square can from the left, and not in the "condenser unit". When I gutted mine, all I replaced in the "condenser can" were the caps. I would still try the original filter caps by bringing up the voltage very slowly on a variac if you have one. Your filter chokes should still be good.
Steve

Hello Steve
Well I put the radio back together with all the original components. The good news is all the tubes and the dial light lights but the only sound I get is a little crackel when turn the channel dial in two locations any ideas?
Thanks Terry.
:Terry: The filter chokes are in the second square can from the left, and not in the "condenser unit". When I gutted mine, all I replaced in the "condenser can" were the caps. I would still try the original filter caps by bringing up the voltage very slowly on a variac if you have one. Your filter chokes should still be good.
:Steve

Hi Steve found all the plate voltages to be about 20 volts lower than they should be. Hopes this helps narrow the possiblities down.
Thanks Terry
:Terry: The filter chokes are in the second square can from the left, and not in the "condenser unit". When I gutted mine, all I replaced in the "condenser can" were the caps. I would still try the original filter caps by bringing up the voltage very slowly on a variac if you have one. Your filter chokes should still be good.
:Steve

Well, at least if you don't have a bad hum, maybe your filter caps are still good. Be sure you hook up a long wire to the antenna post. You won't get much signal without an antenna. As for the low plate voltage, check your resister values with an ohm meter. If they are more than 10% out of tolerance, you may need to replace them. Mine were okay. Carbon composition resisters tend to drift higher in value over time. The wire wound(s) should still be okay. Also check the continuity of your rf chokes with an ohm meter. An infinity reading or very high value (open) means the circuit is broken and the signal won't get through to the next stage. I had to replace mine after a day or so of operating again after 70 years.
Steve

Hi Steve.
Well the radio is working. Not great the volume fades in and out and I can only pick one station but now I know all is not lost. I will check all the things you mentioned. I don't know why it started working but I am glad it did.
Thanks so much for all your help.
Terry
:Well, at least if you don't have a bad hum, maybe your filter caps are still good. Be sure you hook up a long wire to the antenna post. You won't get much signal without an antenna. As for the low plate voltage, check your resister values with an ohm meter. If they are more than 10% out of tolerance, you may need to replace them. Mine were okay. Carbon composition resisters tend to drift higher in value over time. The wire wound(s) should still be okay. Also check the continuity of your rf chokes with an ohm meter. An infinity reading or very high value (open) means the circuit is broken and the signal won't get through to the next stage. I had to replace mine after a day or so of operating again after 70 years.
:Steve

Hi Steve
I can't believe it but the longer I left this radio on the louder it got and now I pick up a lot of stations. It still fades in and out a little but I am tickle pink. It works!!!!
I want to thank everyone again!!!!!
Terry
:Well, at least if you don't have a bad hum, maybe your filter caps are still good. Be sure you hook up a long wire to the antenna post. You won't get much signal without an antenna. As for the low plate voltage, check your resister values with an ohm meter. If they are more than 10% out of tolerance, you may need to replace them. Mine were okay. Carbon composition resisters tend to drift higher in value over time. The wire wound(s) should still be okay. Also check the continuity of your rf chokes with an ohm meter. An infinity reading or very high value (open) means the circuit is broken and the signal won't get through to the next stage. I had to replace mine after a day or so of operating again after 70 years.
:Steve

Wonderful! Mr. Atwater would be proud that one of his radios is alive again. Sounds like you've been bitten by the old radio bug now. You should carefully inspect all the wiring, and replace or cover anything that looks frayed or has brittle insulation. Sometimes I just use wire sleeving this this. Clean the tube sockets and grid caps with contact cleaner, and lubricate the moving parts on the tuning gang mechanism. You should enjoy this fine radio for many years to come. Now what's your next project?
Steve

Hello Steve
Well I have not got all the bugs out of this one the volume went low and stayed there I can still tune in alot of stations but Its hard to hear them. My next project is a AK model 53 in a metal cabinet which I guess is the same as a model 46. I have completely disassembled this one to clean up the main metal bracket that kinded holds the radio componets tegether. Just hope I can get her back together. I did not take the power supply apart on that one.
Thanks again for all the help. I am going to get back to my book on how these old tube radios work so I can figure out why I lost the volume on this one.

Terry
:Wonderful! Mr. Atwater would be proud that one of his radios is alive again. Sounds like you've been bitten by the old radio bug now. You should carefully inspect all the wiring, and replace or cover anything that looks frayed or has brittle insulation. Sometimes I just use wire sleeving this this. Clean the tube sockets and grid caps with contact cleaner, and lubricate the moving parts on the tuning gang mechanism. You should enjoy this fine radio for many years to come. Now what's your next project?
:Steve

Terry: You might try cleaning the volume control pot and wiper arm and see if it improves things. They are open on the back and collect a lot of dust and dirt over the years. Be sure the wiper arm is making good contact with the wire wound. Blow it out with canned air first, then try a little contact cleaner. Also check the continunity of your audio input and output transformers with an ohm meter. Half the secondary on my input transformer was open and I got low volume and distorted audio. The transformers are housed in the square can on the far right (facing the radio), next to the 2 audio amp tubes. You should have plenty of audio from the audio amps in a push-pull circuit. Let us know what you find.
Steve

Terry, are you sure that your filter caps are bad? The original filter caps in my AK55 are good, and some others have reported similar findings. If uncertain, you can bring the set up on a variac and watch the amps.
Doug

:Hello all. I am recapping a Atwater Kent Model 55C radio. Be nice if I could find the caps. My guess is they are located in the 4 square containers that are full of tar. Can anyone tell me if this is so how do I keep track of all the wiring to remove these containers and then how do I get the tar out of them. Can anyone tell me what is in the round shiny metal containers? Thanks for the replies and remember I am a newbie!!!
:
:Terry