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 Post subject: Atwater kent model 42 . 1 ATF
PostPosted: Apr Sun 16, 2017 8:40 pm 
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Joined: Apr Sun 16, 2017 8:25 pm
Posts: 16
hello .

Just a lucky owner of a Atwater Kent model 42 that I picked up at an yard sale in Sweden. I have found a lot of information in the in this site and I am getting there to have a restored radio. I have a broken 1 AF Transformer and I have some problem to replace the caps in the power pack.
Any suggestion on a replacement for the 1 ATF ? and second I can find the negative terminals to the capacitors and "C1" and C3 is easiy to replace but I can not access the positive terminal in the middle "c2" cap with out melting tar. ....

/ regards Roland


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Apr Mon 17, 2017 4:31 pm 
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Joined: Dec Thu 31, 2009 4:28 pm
Posts: 4505
Location: Medford OR
Here are some notes and pictures of an AK 57 that I rebuilt recently:

http://www.russoldradios.com/blog/ak-57

The audio transformer needs to be depotted and a replacement installed inside of the can. Get the transformer from:

http://www.radiodaze.com/audio-tube-dri ... 26-series/

or

http://www.arbeiii.com/Transformers/


Edited to add RD corrected

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Last edited by phlogiston on Apr Mon 17, 2017 10:37 pm, edited 2 times in total.

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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Apr Mon 17, 2017 9:20 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 36533
Location: Livermore, CA
Hi Roland

Atwater Kent service data and modern schematics can be found here:

http://www.atwaterkent.info/TechData/ak ... Index.html

AES, http://www.tubesandmore.com and Radio Daze, http://www.radiodaze.com also sell audio interstage transformers that fit inside original AK cans.

Once some tar is remove from interconnecting wires within the power supply a pin can be used to probe through insulation. Power supply is built in 3 sections. Interconnecting wires go over these sections so not much tar needs to be removed. Using the schematic along with an ohm meter you will be able to determine which wires to cut.

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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Tue 06, 2018 11:07 pm 
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Joined: Apr Sun 16, 2017 8:25 pm
Posts: 16
Hello , still working my atwater mode 42. I am now very close to power up the radio. But still have some issues with voltages on some terminal pins . Terminal 11 on the powersuppy show dont seems to be scaled down to 45 V . Do I need to attach the tubes to get the correct voltages or can I test the volatges with all tubes out ?

regards


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Tue 06, 2018 11:52 pm 
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Joined: Dec Thu 31, 2009 4:28 pm
Posts: 4505
Location: Medford OR
Tubes (load) must be there BUT make you initial test quickly so you can power down if something looks wrong. CAREFUL 700V unloaded.

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"I just might turn into smoke, but I feel fine"
http://russoldradios.com/


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Wed 07, 2018 2:16 pm 
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Joined: Apr Sun 16, 2017 8:25 pm
Posts: 16
Tx for the response , been a little bit hesitant to test but after tripple checking all connections and replaces components I think I am ready to power up .


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Sat 10, 2018 4:11 pm 
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Joined: Apr Sun 16, 2017 8:25 pm
Posts: 16
Success !! I now get the Radio up and running. I use my own small AM transmitter to test. Glad for att the help in the Forum !.
Final thing I need to fix . One of the "belt " is missing to synk the variable capacitors. It is the Right belt that is missing, ie to the detector vari cap.

Two question , any idee who to buy a new one or worst case tips to make a new and how to set the detector varicap in the initial stage ?
Should I put all varicaps at max (ia all baldes in the cap) for all 3 vari caps or are there some more exotic set up performance ?


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Sat 10, 2018 6:06 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 670
Location: Peekskill, NY
The belts are brass. You'll need to find roughly the same thickness sheet brass (around 0.005 inch thick)
and use a paper cutter or a sharp pair of shears to cut a long thin strip. Solder the ends so you get a loop
of the correct length and punch the two holes.


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Sat 10, 2018 8:25 pm 
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Joined: Dec Thu 31, 2009 4:28 pm
Posts: 4505
Location: Medford OR
I think that the belts are bronze - you can solder in a patch if you have the original, but this is not the best.

Here:

http://www.adamsradio.com/home.html

_________________
"I just might turn into smoke, but I feel fine"
http://russoldradios.com/


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Sat 10, 2018 9:40 pm 
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Joined: Apr Sun 16, 2017 8:25 pm
Posts: 16
Hi , Given that I manage to design a belt , next question that I think is more tricky is how to position the varicaps ? Since it is just the detector cap that is out of sync . I need to find a setting that sync with the other two ...


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Sun 11, 2018 2:06 am 
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Joined: Dec Thu 31, 2009 4:28 pm
Posts: 4505
Location: Medford OR
OK This can be confusing.

The important thing to keep in mind is the location of the pins that hold the belts on the center cap. At full right rotation a pin should be strait up. At full left rotation the other pin should be strait up.

So loosen the center pulley with the 2 grub screws and center it so that this is so.

The right and left pulleys will then be relocated so that the single pin fits in the belt - right and left. You must loosen the grub screws AND YOU SHOULD LOSTEN the 3 screws holding the cap. This will allow adjustment without breaking the bands.

Once the bans are correct, the right and left cap can be adjusted visually or by adjusting them for the most signal. They should all look like the plates are in the same position (all 3 caps)

Tighten the grub screws and the 3 bolts holding the right and left caps.

_________________
"I just might turn into smoke, but I feel fine"
http://russoldradios.com/


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Mon 12, 2018 10:50 am 
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Joined: Apr Sun 16, 2017 8:25 pm
Posts: 16
Tx ! I know starting to get to the 2:nd order questions. When the condensor-dial is at "0" I guess that this represent the minimal Cap value? Ie
plate's max out.

Also any idea what frequency range the 0-100 scale represent ?

regards / Roland


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Mon 12, 2018 3:37 pm 
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Joined: Dec Thu 31, 2009 4:28 pm
Posts: 4505
Location: Medford OR
I think it is somewhere around 500 to 1500 kHz.

_________________
"I just might turn into smoke, but I feel fine"
http://russoldradios.com/


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Thu 15, 2018 6:18 pm 
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Joined: Feb Thu 15, 2018 6:12 pm
Posts: 1
phlogiston wrote:
I think it is somewhere around 500 to 1500 kHz.

is this official data? i'm really interested in finding out! thank you


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 Post subject: Re: Atwater kent model 42 . 1 ATF
PostPosted: Feb Sat 17, 2018 3:32 am 
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Joined: Mar Sun 01, 2009 10:27 pm
Posts: 4488
Location: Ann Arbor, MI
One data point. My Atwater Kent model 40 tunes 537 to 1600 KHz. I just got out my signal generator and frequency counter and checked it.

1600 is at 3 and 537 is at 97.
0 does not tune any higher and 100 does not tune any lower.

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Tom


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