Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Oct Fri 31, 2014 8:44 am


All times are UTC [ DST ]



Post New Topic Post Reply  [ 253 posts ]  Go to page 1, 2, 3, 4, 5 ... 13  Next
Author Message
 Post subject: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 4:04 am 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 812
Location: Orland Park, IL
I just bought two radios with nearly identical chassis. One is an Atwater Kent 55C that is built into a table. The other is a stand alone model 55 with the original external speaker. I powered both of these radios up and both are DEAD. Usually, at least the tubes may light up in these radios, but neither one of the radios will light. My first thought is to change the electrolytics, but they don't appear to be conveniently located. I assume they are in one of the boxes above the chassis, but I don't want to go prying them apart until I get a second opinion. Also, I can't seem to get continuity out of the power toggle switch on either of the radios. They are always open circuit, so I tried bypassing it with no change in results.

What would these radios be worth in working condition? I assume the table radio is worth a bit more.


Attachments:
030.JPG
030.JPG [ 196.65 KiB | Viewed 1861 times ]
029.JPG
029.JPG [ 192.17 KiB | Viewed 1861 times ]
028.JPG
028.JPG [ 170.77 KiB | Viewed 1861 times ]
027.JPG
027.JPG [ 189.75 KiB | Viewed 1861 times ]
026.JPG
026.JPG [ 154.52 KiB | Viewed 1861 times ]
Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 5:27 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4934
Location: Bossier City, Louisiana
Evening,

Yes, the Keil table set is more valuable than the table model with separate speaker. However both appear to be in poor shape. Especially the one that goes into the Keil table. Notice the tar that is covering the chassis near the power transformer?? That is rather ominous. Looks as though the transformer overheated. Fortunately you have two chassis and hopefully you can make one operable set. I would pull the 80 rectifier tube and see if any tubes light. If not jumper the on/off switch and ohm out the primary of the power transformer. I would not power them up again with the rectifier tubes in place unless new filter caps are installed. However I suspect by the picture you will probably have one bad power xfmr already. And yes, the filter caps are in that darn tar!


You may want to follow this thread. A LOT of good information there!
viewtopic.php?f=6&t=212455

Good luck with your sets! Keep us posted.

Dave

_________________
Dave

http://pages.suddenlink.net/davesradios/


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 7:17 am 
Member

Joined: Feb Mon 25, 2013 3:39 am
Posts: 1502
Location: Truth or Consequences, NM
That 55c from the table does show leakage from the power transformer. It has been worked on it the past due to parts shown inside.
These things have a lot of variation.
The difference between the 55 and 55c is one is for the cabinet and one is a table version.

Let us know what you are going to do. Will be interesting.

Strange these are showing up in doubles..


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 7:36 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22858
Location: Maryland 20709, USA
lostcauses10x wrote:
Strange these are showing up in doubles..
That is odd.

I believe you have two of them. Were they purchased together or from different sources?

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 8:37 am 
Member

Joined: Feb Mon 25, 2013 3:39 am
Posts: 1502
Location: Truth or Consequences, NM
Different sources with in a month. I bought the cabinet at a yard sale for $20, and a guy standing around said he had one..
Traded him for it and about $3.00 in it.. If you knew just how small the place I live in is, it makes it a bit harder on the odds.

The Original posters sets:
55c looks to be the "late" version. Both bleeder resistor below the RF bias resistor. Long wire to the long antenna lead, line capacitor. Volume control with back on it. Of course Can not be sure how many leads with the photo.

Edited line.

Wiring on transformer type shows the wire from the speaker to #4 on can o caps ( consistent with a c type transformer.) yet does not show the ground lug, so may be a type E transformer.

Cant really count the leads well. Yet there still may be a Type F before AK went down.

ghjkl67
What is the serial Number on the 55c?
Does the volume control have 5 wires off of it??


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 5:52 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22858
Location: Maryland 20709, USA
lostcauses10x wrote:
Yet there still may be a Type F before AK went down.
??? I don't understand that sentence.

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 6:59 pm 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 812
Location: Orland Park, IL
The serial number on the 55c is 4399003. For the model 55, the S/N is 3325807. On the 55c, still no action with the rectifier out. I should mention that the original 80 rectifier that came with the 55c was bad (no continuity, rattling). The one that I used to fire it up the first time was the one from the model 55. I have not tried powering the 55 without the rectifier tube yet. Still working on disassembling. Everything on it is rusted. The 55c from the Kiel table is in better shape cosmetically, so it would be best to part out the model 55 and use it for the 55c. The 55 does not have that black tar, so the power transformer might be okay. Both radios have 5 wires going to the volume control.

What do you think is my first step? I assume that I should swap out the power transformer, but something made it overheat. Might have been a capacitor. Is it necessary to change all the caps on this radio? I was reading this article:

http://www.pharoahaudio.com/ak55cpart1.html

Take a look at page 5. He talks about "reforming" the caps using a variable power source. I don't have a clue how this is done. If the capacitors are bad, this would be one option, or I could just cut the can off and replace the caps.


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 7:03 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7084
Location: S. Dartmouth MA 02748-1225 USA
ghjkl67 wrote:
The serial number on the 55c is 4399003. For the model 55, the S/N is 3325807. On the 55c, still no action with the rectifier out. I should mention that the original 80 rectifier that came with the 55c was bad (no continuity, rattling). The one that I used to fire it up the first time was the one from the model 55. I have not tried powering the 55 without the rectifier tube yet. Still working on disassembling. Everything on it is rusted. The 55c from the Kiel table is in better shape cosmetically, so it would be best to part out the model 55 and use it for the 55c. The 55 does not have that black tar, so the power transformer might be okay. Both radios have 5 wires going to the volume control.

What do you think is my first step? I assume that I should swap out the power transformer, but something made it overheat. Might have been a capacitor. Is it necessary to change all the caps on this radio? I was reading this article:

http://www.pharoahaudio.com/ak55cpart1.html

Take a look at page 5. He talks about "reforming" the caps using a variable power source. I don't have a clue how this is done. If the capacitors are bad, this would be one option, or I could just cut the can off and replace the caps.


The capacitors within any version of an A-K 55 are paper/wax and cannot be "re-formed".

There is no "quick fix" for this model of radio. Taking a shot-gun approach generally results in a great deal of wasted time and has the potential to further damage the radios components.

Suggest reading of all the threads you can find for the AK-55 review the clearly redrawn schematics that are on Leigh's web site. Use the appropriated measurement techniques for resistance and voltage and begin to find out why there is no power either too the power transformer or from it...

Many components in this radio have the potential to change value but outright replacement is not advised until the entire scope of the restoration is reviewed.

With that Good Luck!

Chas

_________________
"Don't find fault, find a remedy"
Former MA lic. radio/tv technician #53401


Last edited by Chas on Mar Sun 24, 2013 7:08 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 7:08 pm 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 812
Location: Orland Park, IL
It seems that somebody has reformed them on this model radio. Either it is possible, or he was lying. It is probably out of the question for me to do something like that anyway because I don't have the proper equipment. All I have is a DC battery eliminator that might reach 60 volts. Should I go ahead and replace all the caps or can any of them be saved?


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 7:50 pm 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 812
Location: Orland Park, IL
UPDATE: I just got the model 55 out of the metal box, bypassed the switch, and is it lighting up (without the rectifier tube). I am having second thoughts about parting it out, if only I could find another power transformer for the 55c. How do I measure the output voltages on the power transformer (before trying it with the rectifier tube)?


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 8:01 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22858
Location: Maryland 20709, USA
ghjkl67 wrote:
Either it is possible, or he was lying.
Reforming of those caps is not possible since they were not electrolytics in the first place.
Draw your own conclusions.

Modern schematics (2-page PDF) here: http://www.atwaterkent.info/TechData/Dr ... 902sch.pdf
Those schematics show the voltages for the filament windings. Those are loaded voltages; unloaded will be higher.

The 55 and the 55C are the same radio electrically; the differences are cosmetic and mechanical.
Electrical differences between your two sets will be a consequence of the changes made during their manufacture.
There are two documented versions of the set, with several other changes incorporated at different times.

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 8:12 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22858
Location: Maryland 20709, USA
AK historically experienced a high failure rate of their filter caps, even when the sets were new/in-warranty.

That's why they came up with the "can-within-a-can" configuration, so the caps could be replaced as a unit.

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 8:48 pm 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 812
Location: Orland Park, IL
The AK 55 is now coming in loud and clear. It looks like the only thing wrogn with it is the power switch. Now, I have to figure out what to do with the 55c power transformer.


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 8:51 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22858
Location: Maryland 20709, USA
I recommend you replace all the paper bypass caps in the metal cans under the chassis before they fail.

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 9:36 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7084
Location: S. Dartmouth MA 02748-1225 USA
ghjkl67 wrote:
The AK 55 is now coming in loud and clear. It looks like the only thing wrong with it is the power switch. Now, I have to figure out what to do with the 55c power transformer.
The easiest test to prove the viability of the power transformer: Remove the rectifier tube, a must do, any other tubes can be left in as well as the pilot light as a tell-tale that AC is on.
Power the set with local fuse, say 2-3 amps in the power line to the 55. Now observe, a ruined transformer will, blow the fuse immediately. One that is about to go will take from a minute to 45 minutes to overheat, If faint frying noises and wisps of smoke exit the wiring then the transformer is bad. This test cannot ruin a good transformer, I did it to my 55 ran it for some 2 hours and the case was only slightly warmer than room temperature. I had only the pilot light present. The best advise if the transformer is bad is to get a used one as it will "drop fit" Having to wrestle with the asphaltic filler is a nuisance at best. Follow the threads, there is one with how to deal with the capacitor block in a sane manner by extracting only the bottom plate with the terminals and using Vectorboard to mount new Mylar capacitors. Since the values required are so low, Mylars would probably never have to be replace...

Good Luck

Chas

_________________
"Don't find fault, find a remedy"
Former MA lic. radio/tv technician #53401


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 10:48 pm 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 812
Location: Orland Park, IL
So would you recommend dropping in another transformer and using this test without having to do anything to the capacitors? It sounds fairly simple, but I have decided not to part out my other AK 55. It is working too well to rip apart. What are my chances of finding another transformer?


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 11:36 pm 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 812
Location: Orland Park, IL
I found one on eBay that might be good for parts.

http://www.ebay.com/itm/Atwater-Kent-Mo ... 20d0392e98

I could either swap the tubes from mine and use this one, or I can replace the power transformer and use my orinigal radio. I will probably use my radio. Other than the black tar, the chassis looks so clean as opposed to the one on eBay. Notice how it is a 55c model inside a stand alone box. I thought the 55c's were made for the table?


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Sun 24, 2013 11:51 pm 
Member

Joined: Feb Sun 24, 2008 4:21 am
Posts: 3460
Location: Sedona, AZ
That on e-bay would be a 55, not a 55C.
Jerry

_________________
A friend in need is a pest. Bill Slee ca 1972


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Mon 25, 2013 12:49 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22858
Location: Maryland 20709, USA
JerryHawthorne wrote:
That on e-bay would be a 55, not a 55C.
That only matters if you need some front-panel mechanical parts.

Electrically the two sets are identical.

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Atwater Kent Model 55 & 55C
PostPosted: Mar Mon 25, 2013 1:24 am 
Member

Joined: Feb Mon 25, 2013 3:39 am
Posts: 1502
Location: Truth or Consequences, NM
JerryHawthorne wrote:
That on e-bay would be a 55, not a 55C.
Jerry

It a 55C in a table cabinet. Serial number confirms this. Seeing a lot of them that way recently.
The transformer has the bar attached That is a 55c version transformer.
(seems to be the only difference short of the front panel of the 55.

It does have the covered variable resistor so might be compatible. Good to have parts for both.
The original documents state that only a type E transformer should be used with a type E.

As the owner how many wires are attached to the volume resistor.


Top
 Profile  
 
Post New Topic Post Reply  [ 253 posts ]  Moderators: Marcc, Norm Leal Go to page 1, 2, 3, 4, 5 ... 13  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 8 guests



Search for:
Jump to:  




















Privacy Policy :: Powered by phpBB