The PHILCO Phorum
Nathan's 112 Highboy - Printable Version

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RE: Nathan's 112 Highboy - Nathan Slingerland - 02-05-2018

Dial Cord

Next up was the dial cord. I measured the original and came up with a total cord length of 20" with about 1.25" folded back to form the loop on each end. Thread is wrapped around the end of the loop to hold everything together.

Each end looks like this:
[Image: https://farm5.staticflickr.com/4609/28292507279_755149b4ab_z.jpg]

The original cord measured 0.065" (~1.7mm). This is pretty thick cord - and my initial attempts to replace it with thinner material (0.040") did not work well.

I searched around and saw a suggestion to try braided fishing line. That led me to this search Amazon where I found this 400lb rated kevlar line:
https://www.amazon.com/gp/product/B005467UHQ/

This sounded like a good material to use - exact right diameter, low stretch and high temperature.  Icon_thumbup
And bonus: at $13.99 for 50' that's a bargain compared to what dial cord normally runs!

I patiently (ha) waited the required 2 days for Prime shipping and returned to making the dial cord:
[Image: https://farm5.staticflickr.com/4703/40058035812_e628f961c6_z.jpg]

I wrapped the ends with black thread and used hot glue to bind the thread together. I used a heat gun to reheat the glue and get it to flow into the thread. No danger of melting the cord - it's good to over 900 degrees F!
[Image: https://farm5.staticflickr.com/4616/39192101185_0c43261631_z.jpg]

I didn't do this until after installing the cord for the first time - but because the kevlar cord is fairly smooth I ended up rubbing it with instrument rosin to make it a bit stickier.
[Image: https://farm5.staticflickr.com/4610/28309964129_b2731c28d7_z.jpg]

I ordered this one from Amazon: https://www.amazon.com/gp/product/B0002D0L4A

Dial Cord Stringing

Here's how to string the cord step by step. I removed the dial lamp and mask (one screw each) to make things more accessible. I also took the dial off for cleaning.

First, find the large gap in the dial cylinder and thread one end the cord through without the spring. Then attach the spring.
[Image: https://farm5.staticflickr.com/4662/39192100105_b35b33b5fe_z.jpg]

Note the two holes in the dial cylinder. Attach the spring to the top-most hole.
[Image: https://farm5.staticflickr.com/4710/28309957489_6354dac820_z.jpg]

Now we want to wrap the cord around the groove in the cylinder around the back.
Push the cord around the back of the cylinder and rotate the cylinder up/toward the radio.
[Image: https://farm5.staticflickr.com/4617/39192100075_f8390fde21_z.jpg]

There are three pulleys to thread the cord through.
[Image: https://farm5.staticflickr.com/4705/28309957189_26f826e5d4_z.jpg] [Image: https://farm5.staticflickr.com/4708/40058028732_33c86e15d5_z.jpg]

[Image: https://farm5.staticflickr.com/4654/39192099085_7df8400cf6_z.jpg]

Now we're ready to thread the other loop end back into the cylinder and attach it with the other spring:
[Image: https://farm5.staticflickr.com/4765/26216486528_e741cba388_z.jpg]

Done!

As mentioned above I ended up repeating the cord stringing a second time because I noticed after the initial install that it worked 99% of the time but there was still one point in the dial where it slipped. I took the cord off again and rubbed it with rosin. After that it worked perfectly. Another option would be to make a slightly shorter cord (maybe 1/4") to give more tension.

Dial Cleaning
I've had good success using Goo Gone for dial cleaning. I still test cleaning an inconspicuous bit of printing like the Philco part number on the dial before going ahead with the rest of the dial. But I have yet to find a dial where the printing was affected by it.
[Image: https://farm5.staticflickr.com/4700/40058027242_633451870a_z.jpg]

RE: Nathan's 112 Highboy - Radioroslyn - 02-05-2018

Good Job!
I might have given round shoe laces a try just because the availability is a little better.

RE: Nathan's 112 Highboy - Nathan Slingerland - 02-05-2018

Round shoe laces - that sounds like a good option too. Icon_thumbup

RE: Nathan's 112 Highboy - Nathan Slingerland - 02-08-2018

Alignment

With the all the caps replaced it's ready for alignment. I generally rely on the Rider's books 'Aligning Philco Receivers'. I have the paper editions, but they're also available online:
https://archive.org/details/AligningPhilcoReceiversV1
https://archive.org/details/AligningPhilcoReceiversV2

In fact the official Philco service bulletin for the 112 (#101 in the case of this model with 47 tubes) doesn't even include alignment instructions:
   

I guess not many service people had the right equipment when the 112 was released?
Actually there is another service bulletin (#60) titled 'Adjusting Model 112' that might have that - but I don't have that bulletin in any case.

The process went smoothly and it plays well.
[Image: https://farm5.staticflickr.com/4743/40091051541_b0f98c90e2_z.jpg]

Speaker Rewire

The speaker cable has definitely seen better days. A good bit of the insulation was deteriorated near the plug. At the start I temporarily painted that with liquid electrical tape.

[Image: https://farm5.staticflickr.com/4741/25218759107_98b6a2f780_z.jpg] [Image: https://farm5.staticflickr.com/4629/39192109645_9a9b817bb9_z.jpg]

But the time has come to do come up with a more permanent fix. EDIT: See Ron's much better solution below - it turns out it is *not* necessary to drill out the transformer rivets. Sadly replacing the wires means drilling out the rivets on both the plug end as well as the output transformer on the speaker. The transformer's terminals are underneath the transformer - no way to access them without removing the transformer first. Icon_thumbdown

[Image: https://farm5.staticflickr.com/4656/26271412398_d365518f90_z.jpg] [Image: https://farm5.staticflickr.com/4624/28364942169_ea3ffa6c00_z.jpg]

So what color should the new wire be?
The original colors of the wires have all faded to to an insipid yellowish-brown color...or have they? Actually there's unfaded bits of wire under both the output transformer and inside the plug.

[Image: https://farm5.staticflickr.com/4605/40145085311_74901f335c_z.jpg] [Image: https://farm5.staticflickr.com/4654/39433283644_8f7735f5f1_z.jpg]

As far as I can tell the wires were originally:
Each wire was a total of 21.5" in length.
Plug end was stripped to 3/4".
Speaker end was stripped to ~1/2"
Brown thread used to hold wires together. Located at 2" from plug end, 1.25" from speaker end.

[Image: https://farm5.staticflickr.com/4770/39433282484_06885d9489_z.jpg] [Image: https://farm5.staticflickr.com/4619/40145084041_2d0a4a8983_z.jpg]

I really don't like removing rivets because I have yet to find a way to redo them in a way that looks clean and original. Hopefully someday I'll have a better way but for now I'm replacing them with machine screws.
I used 4-40 x 3/8" machine screws for holding together the plug and 8-32 x 1/4" machine screws for remounting the output transformer.

[Image: https://farm5.staticflickr.com/4662/25273275967_bfcc80122e_z.jpg]
[Image: https://farm5.staticflickr.com/4616/25273275597_33d4889f71_z.jpg]

Now to run the new wires to the speaker. The original rubber grommet was petrified so I replaced it.
[Image: https://farm5.staticflickr.com/4745/28364939689_14baf0ab6b_z.jpg]

All back together:
[Image: https://farm5.staticflickr.com/4610/28364939539_1b83dc02ee_z.jpg]

RE: Nathan's 112 Highboy - Ron Ramirez - 02-08-2018

Nathan Slingerland Wrote:Sadly replacing the wires means drilling out the rivets on both the plug end as well as the output transformer on the speaker.

Next time, remove the speaker cone. That way you won't have to drill out the audio transformer rivets - unless the transformer is bad.

Quote:I searched around and saw a suggestion to try braided fishing line. That led me to this search Amazon where I found this 400lb rated kevlar line...

Now that's a great idea! Icon_thumbup Icon_thumbup Much better than my crochet nylon idea of several years back, before Amazon. At the time I wished that I could find something better but could not find anythnig locally like the heavy fishing line you found. That is great!

RE: Nathan's 112 Highboy - Nathan Slingerland - 02-08-2018

(02-08-2018, 06:54 AM)Ron Ramirez Wrote:  Next time, remove the speaker cone. That way you won't have to drill out the audio transformer rivets - unless the transformer is bad.

The speaker cone can be removed? Mind blown!
How do you separate it from the edge of the speaker? Heat?

RE: Nathan's 112 Highboy - Ron Ramirez - 02-08-2018

No, just do the following:

Unsolder the voice coil leads from the terminals on the speaker frame.

Remove the screws from around the perimeter of the speaker cone.

Remove the screw from the center of the speaker spider.

Carefully pull the cone away from the frame. The gasket at the edge is likely stuck to the frame; careful use of a sharp knife blade will assist in getting the gasket free from the frame. A little bit of acetone carefully applied between the gasket and frame might help. The cone is glued to the gasket on the bottom side of the gasket (against the frame), so work very carefully and slowly being careful not to cut or tear the cone. Patience is a virtue.

Set the cone/gasket assembly aside and do what you need to do inside the frame (replace wires, etc.).

Reverse the above procedure to reinstall.

RE: Nathan's 112 Highboy - Radioroslyn - 02-08-2018

+1
Also while you have it apart vacuum out the gap between the pole and frame. They tend to accumulate dust that could inhibit the cone movement.
Great job so far!!

RE: Nathan's 112 Highboy - Nathan Slingerland - 02-08-2018

Thank you for the great advice! I will definitely do it that way next time.

For some reason I had assumed that the cone was glued to the frame not the gasket. It's great news that I was wrong. Icon_biggrin

RE: Nathan's 112 Highboy - Steve Davis - 02-09-2018

Nathan, I know it is too late to help on this one, but I posted a "how to" in the tech section, on how to replace speaker wires without drilling the rivets out of the plug. Look here.   http://www.philcoradio.com/phorum/showthread.php?tid=17924   

Steve

RE: Nathan's 112 Highboy - Nathan Slingerland - 02-09-2018

Very clever! I will definitely try that next time. Thank you for taking the time to write it up!

RE: Nathan's 112 Highboy - Radioroslyn - 02-09-2018

Tnx for posting Steve!
I was cleaning up the basement a bit yesterday and found a Philco spkr plug that needs new wires. Quite timely post. I tend to forget what's here on the Phorum sometimes just some little things that can make a good job great.

RE: Nathan's 112 Highboy - Nathan Slingerland - 02-19-2018

Thankfully I know what to do next time but for this particular speaker I'd still like to find a better solution than machine screws for the drilled out rivets.

Maybe rivets?  Icon_think

At some point I bought these rivets based on a post here on the Phorum - the idea being to take the rivet of the mandrel and manually compress it.
That didn't work so well when I tried it - the copper is just too soft - and the rivet would deform side to side.

I decided to try an actual pop rivet tool - Marson 39000 HP-2 Professional Hand Riveter from Amazon - and see how that would work.

Here's what the pop rivets look like:

[Image: https://farm5.staticflickr.com/4629/38559579780_d7ce35170f_z.jpg]

And the box:
[Image: https://farm5.staticflickr.com/4677/39658993954_9234e258af_z.jpg]

Basically you insert the pop rivet like so:

[Image: https://farm5.staticflickr.com/4704/39473071885_a9627c7964_z.jpg]

Then put the rivet gun over the pointed end and gently (!) squeeze until the rivet 'pops' - center brass mandrel breaks off.

[Image: https://farm5.staticflickr.com/4613/40324460372_86f733e5c0_z.jpg]

I was left with these:

[Image: https://farm5.staticflickr.com/4749/39658994074_87a6fd0fc4_z.jpg]

The result is pretty nice - almost as good as the original from the back side of the plug:

[Image: https://farm5.staticflickr.com/4762/25497854647_1fff493eac_z.jpg]

The front side looks OK - but most importantly it's no where near as thick as the machine screw head.

[Image: https://farm5.staticflickr.com/4628/39658993684_eafe851c27_z.jpg]

RE: Nathan's 112 Highboy - Nathan Slingerland - 02-19-2018

And of course now I find the original post - why I bought the rivets in the first place. Morzh posted about doing something similar with a newer style speaker plug on the Model 18: http://philcoradio.com/phorum/showthread.php?tid=6326

Wow! I would never have tried the rivet tool if I had read the original post again recently.

I would guess that success or failure (cracked bakelite) depends greatly on the specific characteristics (softness, grip range) of the rivets.
There's also two options for the mandrel - steel and brass. Perhaps that's the difference with Mike's experience (the brass mandrel being softer and breaking off easier)?

Maybe I should go buy a lottery ticket...

RE: Nathan's 112 Highboy - morzh - 02-19-2018

I was about to post but then I saw you found it.