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 Post subject: Philco 41-255 step-by-step chassis restoration...DONE.
PostPosted: Dec Fri 10, 2010 11:22 pm 
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Joined: Mar Mon 17, 2008 3:51 am
Posts: 3982
Location: Conway, Arkansas
I really wanted to start this restoration at the end of October, but it just didn’t happen folks. Please accept my
apology. I’ve been working like a dog (like a dog I tell ya) trying to get my Heathkit HW-101 Ham rig and G5RV antenna
up and operational. The antenna sure looks fine suspended in the trees. Too bad my voice isn’t transmitting from it.
But not to worry…yours truly is fast zeroing in on the last of the problems.
Meanwhile, since I’m severly suffering from vintage radio restoration withdrawal, here at last is the ole Philco
41-255 restoration thread I promised. For those of you who haven’t yet seen it…this is our victim:
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Let’s take the traditional inspection tour:
Dusty, dirty, nasty, but she looks just great to me. I even like her heavier than normal musty odor:
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Believe it or not, the tuner plates still move as smooth as silk:
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The front sorta sucks. Don't let it hurt your eyes:
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Great-looking splice job. Not a problem: chop, chop. And check out that cord. Looks like a rat's intestine:
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Always a broken dial cord. No sweat...we can deal with it:
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This metal box is the only really rusty spot on the chassis. Could spell trouble underneath…maybe a cooked transformer. If so, we’ll just have to fix it:
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The underside isn’t too bad. Note all the original caps and such. I'm happy to see that:
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The cabinet veneer is in great shape…one of the reasons I bought this critter:
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There is some slight wood separation on each side. A caveman could repair it:
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Even the bottom is good to go:
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The inside also looks good:
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Has the original stickers:
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And the speaker appears to be unmolested:
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That's it for the inspection. It's time to pull the tubes and get to cleaning.
This radio has more than its share of loktal tubes. Note the bumps on their bases:
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Those bumps show you which direction to tilt the tube when removing it from the socket. Failure to do it that way will often result in a broken tube or damaged socket. So be sure to always do it like this:
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Now for a little air:
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Things are looking better already. This one is going to be a piece of cake:
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I usually start a restoration by working on top of the chassis, then going underneath. But this time I've decided to start deep in the bowels where the screwed up wires, bulging wax caps and driftwood-looking resistors live. So the first thing we'll do is check out each of the coils...wise advice gifted to me years ago by my good friend, Allamericanfiveradio.
Is anyone still interested in seeing this mess?

_________________
John


Last edited by badrestorer on Apr Thu 28, 2011 3:47 am, edited 13 times in total.

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 Post subject:
PostPosted: Dec Fri 10, 2010 11:29 pm 
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Joined: Jun Sat 02, 2007 1:37 pm
Posts: 1365
Location: Ennismore, Ontario
I am tuned in and awaiting the next segment.

Brian

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Brian

I came into this world with nothing...
I have been able to keep most of it.


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 Post subject:
PostPosted: Dec Fri 10, 2010 11:33 pm 
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Joined: Oct Sun 11, 2009 1:43 am
Posts: 197
Location: Long Beach, California; 90808
AAH finally John. I had been in severe withdrawal awaiting the start of this project.

thanks
Ron

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It is better to know some of the questions than all of the answers. James Thurber


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 Post subject:
PostPosted: Dec Fri 10, 2010 11:34 pm 
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Joined: Jan Sun 06, 2008 3:28 am
Posts: 2857
Location: Richmond, VA
Git 'er done :lol:

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Ed


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 Post subject:
PostPosted: Dec Sat 11, 2010 2:18 am 
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Joined: Oct Mon 25, 2010 3:42 am
Posts: 769
Location: Bethel Springs,TN
This looks like fun and great stuff for a new guy like me.
Frank in Tennessee


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 Post subject:
PostPosted: Dec Sat 11, 2010 3:18 am 
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Joined: Mar Sat 06, 2010 11:41 pm
Posts: 268
Location: Magic Valley, Idaho
Watching with anticipation :D

lets see it done!

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Wyatt W.


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 Post subject:
PostPosted: Dec Sat 11, 2010 3:24 am 
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Joined: Dec Sun 02, 2007 3:20 pm
Posts: 1510
Location: North Dakota
I've done a couple of radios with a very similar chassis ( a 40-150 and a 40-180). I will therefore be following this thread with great interest!

Don


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 Post subject:
PostPosted: Dec Sat 11, 2010 3:48 am 
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Joined: Jan Wed 09, 2008 9:03 pm
Posts: 4273
Location: Indiana
if your lucky the off on switch is good , if not I can tell you what I had to do with mine but is easy fix , Staying tuned in , Your Friend ,Dan

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 Post subject:
PostPosted: Dec Sat 11, 2010 5:23 am 
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Posts: 2857
Location: Richmond, VA
Daniel Hilderbrand wrote:
if your lucky the off on switch is good , if not I can tell you what I had to do with mine but is easy fix , Staying tuned in , Your Friend ,Dan


I'd like to know. The Sparton 121 I'm working on has a bad on/off switch. It's on the tone control pot. I know I'll never find another one. To avoid going OT on this thread, maybe make a new post? Or PM me?

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 Post subject:
PostPosted: Dec Sat 11, 2010 1:58 pm 
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Joined: Jan Wed 09, 2008 9:03 pm
Posts: 4273
Location: Indiana
these type of Philco's used a push push type switch mounted at the end of push button assembley , lot of them are bad , there has been other threads on how to fix (replace) switch , I have my own way of replacing the switch I like a little better , Good Luck Daniel

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 Post subject:
PostPosted: Dec Sat 11, 2010 7:33 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 224
Location: Rothschild, Wisconsin
Do you have a replacement dial? I have one that looks to have the same bands and dial markings (I think from a 41-280) that is yours for postage. The Philco part number on the right side of the dial is 27-5655. The one I have is in very good condition.


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 Post subject:
PostPosted: Dec Sat 11, 2010 9:23 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 5877
Location: Cleona, PA
Love following your threads. Carry on.

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Reece


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 Post subject:
PostPosted: Dec Sat 11, 2010 11:09 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3059
Location: Boston, MA USA
How is the wiring? These sets were infamous for their rubber-insulated wiring that tends to crack and fall away. But the wiring in my very similar 41-250 is fine.

-David


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 Post subject:
PostPosted: Dec Sun 12, 2010 5:15 am 
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Joined: Jul Sat 11, 2009 4:18 am
Posts: 74
Location: Ephrata, Wa.
I've got a 41-250 waiting to be gone through. I'm sure there's enough similarities between the two so this project will be a big, big help! Thanks for taking it on.

Len


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 Post subject:
PostPosted: Dec Sun 12, 2010 7:09 am 
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Joined: Aug Tue 24, 2010 8:56 pm
Posts: 3466
Location: Florida
Sure, I'll stay tuned.

I can see you'll have your hands full replacing some rubber wiring, but at least the bottom of the power trans doesn't have the dreaded blobs of black tar coming out of it.

Oh, and thanks for the tip; I didn't know that the dimples on loktals indicated direction.


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 Post subject:
PostPosted: Dec Wed 15, 2010 12:09 am 
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Joined: Jul Mon 13, 2009 3:15 am
Posts: 513
Location: Sydney, Australia
Well, I'm back - and so are John's restorations! haha

Anyway, this one looks a bit rough. Good luck!

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VK2FBAH

Studying for my advanced-grade ham licence.


Last edited by Chirpolo on Dec Wed 15, 2010 12:25 am, edited 1 time in total.

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 Post subject:
PostPosted: Dec Wed 15, 2010 12:20 am 
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Joined: Jun Thu 17, 2010 5:41 pm
Posts: 1595
Location: Dawson Creek BC, Canada
I'll be watching.

Nick

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Life without music would be a mistake-Nietzsche
I am not accountable for any damage this causes


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 Post subject:
PostPosted: Dec Wed 15, 2010 12:44 am 
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Joined: Mar Mon 17, 2008 3:51 am
Posts: 3982
Location: Conway, Arkansas
(Note: On my puter screen the wording in this posting far exceeds the right edge. I don't know why...never had it happen before.)

My job, my Heathkit transceiver repairs, Christmas shopping with the wife, wrapping, packing and shipping what she bought have
all been putting a severe crimp in my restoration style. But I finally found some time to start checking out the coils in this dog.
Here they are:
A. Primary and secondary windings of the power transformer
B. Local oscillator.
C. Primary and secondary windings of the IF transformers (IF cans).
D. Primary and secondary windings of the audio output transformer.
E. This radio has seven pushbutton tuning coils.
F. Antenna coil(s).
G. Speaker field coil (found on electromagnetic speakers).
H. Anything else that remotely smacks of being a coil.

Let’s start with the power transformer primary winding. The large arrows are the multimeter red and black lead connection points.:
Image

This is the on/off switch. It's operated by pushbutton:
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It’s difficult to make out on the schematic, but I think we should get 12-ohms for this reading. Hey...10.3-ohms suits me just fine:
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The secondary is center-tapped, meaning it’s divided into two halves…upper and lower. We’ll first measure the entire winding…plate to plate on the #84 rectifier tube, pins 2 to 3:
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Looking good. I like it:
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Now let’s individually measure the secondary top and bottom halves, pin 2 then pin 3 to the non-grounded end of the Candohm resistor (circled in blue on the schematic and green in the chassis). The grounded end is circled in orange.
The combined readings should of course add up to almost 272-ohms:
Image
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129-ohms plus 142.5-ohms equals 271.5-ohms. We’ll take that:
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Last up is the power transformer filament winding, pins 1 & 5:
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We have continuity, but it’s much higher than the "less than .1-ohms" value shown on the schematic. I’m not sure what to think about this:
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At least the power transformer isn’t fried (a big load off my mind), so let’s move on to the pushbutton tuning coils. There’s seven of them. Each should read only a few ohms.
The schematic shows that one end of each coil is grounded, so the black lead was simply clipped to the collective ground wire (yellow arrow). The red circles show the connection points for the red multimeter lead:
Image
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There was a little bit of variance, but all seven coils are good to go:
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We’ll finish up with the audio output transformer:
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The secondary winding comes first. The transformer’s metal frame is riveted to the chassis, thus providing the ground as shown in the schematic, so the black multimeter lead is connected to the chassis. The red lead is connected to the terminal in the red circle:
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Generally speaking, audio output transformer secondary readings are fairly low.
We can live with this:
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The center-tapped primary will be the final reading for this posting. The striped wire in the pic is the centertap. From there to the black wire is the bottom half of the winding. From the striped wire to the white wire is the top half:
Image

And the bottom half reading is (ignore the number one).
Uh-oh...I'llllllll be back!:
Image

_________________
John


Last edited by badrestorer on Dec Wed 15, 2010 4:45 am, edited 8 times in total.

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 Post subject:
PostPosted: Dec Wed 15, 2010 12:51 am 
Member

Joined: Jul Mon 13, 2009 3:15 am
Posts: 513
Location: Sydney, Australia
John - the page is too wide because two pictures are side by side. I'm not sure how you maganged that [lol], but between the 6th and 7th pics from the top, press enter to space them out. Mabye that'l fix something.

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VK2FBAH

Studying for my advanced-grade ham licence.


Last edited by Chirpolo on Dec Wed 15, 2010 12:53 am, edited 1 time in total.

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 Post subject:
PostPosted: Dec Wed 15, 2010 12:51 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 680
Location: Warren, Ohio, USA
Badrestorer:

Your text is wider due to the width of the pictures. Not a big deal. Love these threads.

Steve Chambers


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