Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco 89B, Detector coil repair
#1

I posted several days ago on the WANTED forum looking for a replacement coil.  See https://philcoradio.com/phorum/showthread.php?tid=20069.  After reading the posts there and discussing with Terry via PM I may consider trying to rewind the open coil.

The open coil is the small primary winding.  I have posted several pictures of the coils condition.  In PM discussions with Terry it looks like I could rewind with 25 turns of 34 gauge wire and the direction of the winding is not of concern.

My problem is the removal of the old winding and what looks like the melted remnants of the nitrocellulose material separating the two coils.  Also wondering if the secondary coil may be damaged by the melted remnants although it does show continuity.

An comments or quidance is appreciated.

Thanks, Bob


Attached Files Image(s)
       
#2

I've rewound several of these and have never had a problem with the wire underneath the primary.  Once cleaned up, I usually coat the underlying wire with shellac before installing a replacement for the nitrocellulose.
#3

Is there a proceedure for removing the crusty remnants of the nitrocellulose?
#4

After unwinding the outer coil, most of the residue can be removed with your fingernail.

Steve

M R Radios   C M Tubes
#5

https://www.philcorepairbench.com/rewind...-rf-coils/

Ignore the model numbers and # of turns as those are for early sets than yours but the procedure is the same. I've never done the ammonia thing.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#6

NO! do not use ammonia. Ammonia will corrode copper.

Steve

M R Radios   C M Tubes
#7

I was able to remove what remained of the coil wire and nitrocellulose.  Still have continuity on the secondary so guess I am good there.  I will follow the procedures outlined in the above reference but avoid the ammonia.  Any recommendation on cleaning other than ammonia? I counted the turns at either 13 or 14 - hard to tell because the wire was in a lot of pieces.  Does that sound about right for the number of turns?

Bob
#8

> Any recommendation on cleaning other than ammonia? 

I would leave it alone. Any sort of cleaning may disturb the enamel coating on the secondary.

>Does that sound about right for the number of turns?

Sound good.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#9

The primary isn’t a tuned circuit so the exact number of turns is not super critical. I would go with the 14. If it doesn’t work well,it would be easier to remove a turn than add one.

Steve

M R Radios   C M Tubes
#10

I finished it up today.  Went with 14 Turns.  Will be a while before I will be able to test it.  Thanks for the help.

Bob




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
An attempt to remove the Field Coil from a G speaker
Thanks Chas, sure will give it a look!morzh — 03:39 PM
An attempt to remove the Field Coil from a G speaker
Mike, Lookup  murrayatuptown on ARF. Seems he has a dilemma with surplus field coils. Could get lucky and have what y...Chas — 01:26 PM
Atwater-Kent 84, restoration.
Hello Mike, I have not checked to see if my console has a fuse or not and far as sets go I have early 30s General Motor...radiorich — 11:25 AM
Atwater-Kent 84, restoration.
Ron I forgot, but when you said "phone number", I remembered, caus I usually remember how I act when I need...morzh — 11:12 AM
Atwater-Kent 84, restoration.
You have an extensive collection of Philcos, Mike! I’m always excited to see each new one. Agreed on the power supply fu...jrblasde — 10:50 AM
462ron
Hi Mike, that 84 sure looks great. You don’t often see these antique radios with a fuse like yours has. I usually instal...462ron — 10:22 AM
Atwater-Kent 84, restoration.
Hello Mike, Wow ! far as my AK it does work and the cabinet is in nice shape so is my chassis anyway here is a photo of...radiorich — 02:59 AM
Atwater-Kent 84, restoration.
Nice radio, Mike! Here's hoping it was well rebuilt. Take care and BE HEALTHY! GaryGarySP — 12:12 AM
Atwater-Kent 84, restoration.
Rich yes, this is the way I got it. I have just put it on the table and took it apart. I suspect it even might work,...morzh — 11:31 PM
Atwater-Kent 84, restoration.
Hello mike, What nice looking radio I have one AK in my collection it's a console I have not started restoring it yet ....radiorich — 11:21 PM

[-]
Who's Online
There are currently 3159 online users. [Complete List]
» 1 Member(s) | 3158 Guest(s)
Avatar

>