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My Next Project: Log Cabin
#16

Good advice, guys.  Actually, last week I bought a needle file and gently cleaned all the Loctal sockets.  I inserted the file ever-so-gently, less than ¼ inch, and removed it as soon as I felt any resistance.  But when I put the tubes back in, each one slid in with practically no resistance.  I thought I had destroyed all five sockets and started considering replacing them, but the next morning they felt tighter.  After 24 hours they were back to normal.  With the tubes back in, I checked the continuity of each pin to its chassis connection.  


The original output transformer is OK, but it is interesting that the one in my parts set did have an open primary.  

After all the tube jiggling and circuit tracing everything fell into place and I got a decent alignment.  And, Mike, I really do have a half-dozen PF Chang chopsticks that I use for probing live circuits.   Reception is good.  Volume is good.  And there is no hum!  BUT…
 
…I have a problem with the speaker(s).   The original speaker needs reconing, and I’m trying to learn how to do that, but the “good” speaker (from a 41-255) sounds terrible.  I won’t try to describe it, but I’m sure that the problem will be recognized by listening.  This is a 20-second video.  In the middle of the video I demonstrate that slight pressure on the dust cap or the periphery of the cone corrects the problem.

https://photos.google.com/photo/AF1QipMD...x8RVSDoTKj

Any advice will be greatly appreciated.  Does someone know what’s wrong with the speaker, and is it repairable without reconing?
#17

Am I the only one who gets a 404 error (The requested URL was not found on this server.) when they click that link ?
#18

(02-01-2016, 04:23 AM)mikethedruid Wrote:  Am I the only one who gets a 404 error (The requested URL was not found on this server.) when they click that link ?

I get a request to sign into Google when I click that link.

W.D., just guessing since I can't access your link, but if the sounds clears up when you touch the periphery of the cone your voice coil might be rubbing:

http://www.philcoradio.com/phorum/showth...?tid=11056

John KK4ZLF
Lexington, KY
"illegitimis non carborundum"
#19

Sorry about that link.  I didn't know that the CIA had classified it.  Here's an unclassified version:

https://picasaweb.google.com/lh/photo/JQ...directlink

(it worked for me after I signed out from Google)

I read Ron's post about re-shimming the voice coil.  I'll try that today.  Thanks.
#20

I spent over three hours working on the speaker last night.  The instructions that Ron posted to recenter the cone were easy to follow.  The only glitch was that business-card shims were too thick.  I used plastic strips which were probably less than half the thickness of a business card, and it was quite difficult to get three shims in.


[Image: https://lh3.googleusercontent.com/-2H3OB...center.JPG]

I let the adhesives set overnight and tried it out this morning.  It was very gratifying to hear good audio from that speaker.  This is a link to a 15-second video with before- and after-repair audio.

https://picasaweb.google.com/lh/photo/Ux...directlink

Thanks for the help.  For anyone trying this procedure for the first time, here’s of series of photos of my work:

https://picasaweb.google.com/coldrb/Spea...directlink
#21

Great job   Icon_thumbup 

Your pictures and tutorial may help some other poor soul with a distorted speaker.

John KK4ZLF
Lexington, KY
"illegitimis non carborundum"




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