1936 Philco 116PX Electronic Restoration - Printable Version

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+--- Thread: 1936 Philco 116PX Electronic Restoration (/showthread.php?tid=16945)

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-16-2017

Here's the original grille cloth pieces. They were not salvageable.  

[Image: https://farm5.staticflickr.com/4445/23873965848_3506d8b31e_b.jpg]

I even tried taking a couple smaller pieces from the large one to cover the 2 smaller pieces. They were too stained and thin, even after a gentle hand washing.

I emailed Kenny Richmond, and asked him if he had a couple smaller pieces he could sell me of his Philco Chevron pattern, and mentioned which radio it was for.
He very generously sent me a piece complimentary, with a request that I send him pics of the unit when It's done. He is working on putting together a webpage documenting rare units, and knowing how rare this is, he asked if I'd be willing to let him put it on his site. I of course agreed.

The cardboard forms for the smaller pieces were worn and not stiff anymore. The cloth would not stretch tight without bending the cardboard- it just didn't look good.  
So I opted to cut out some new ones from some foam core board I have.
They turned out ok. Since they are not seen anyway, they'll do.  

[Image: https://farm5.staticflickr.com/4459/37469148170_d6b08a12c8_b.jpg]

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-16-2017

While I had them removed, I decided to see if I could do anything about the melted rubber that supports the back end of the acoustic clarifiers.

[Image: https://farm5.staticflickr.com/4475/23873976378_2383d14218_b.jpg]

[Image: https://farm5.staticflickr.com/4444/37678693156_e09531f3a3_b.jpg]

I posted on the Facebook Philco Group, and was directed to a video Eddie Brimer did of how he rebuilt his.

I drove around to a couple places, and wound up with some wide orange NBA rubber bracelets to use. Using a leather hole punch for the holes, and cutting them to length, I was able to install them neatly after cleaning the old rubber out carefully with an x-acto knife.  
Again, since they aren't seen, they'll do....

[Image: https://farm5.staticflickr.com/4489/37694794902_8ffce8fb88_b.jpg]

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-16-2017

I checked out most of the resistors , coils and chokes, and all checked out within reasonable tolerance.  

At this point, all I had left to do was install the new power cord and plug.

That was done early this evening, and at around 8:30pm PT, I took a deep breath, plugged it into my variac, and slowly brought it up.  

This video was taken during that 1st power up test.  

[Video: https://youtu.be/xQr6npbvtZs]

This video only demonstrates the AM band, with no alignment done yet.  

I'm happy to report all bands were receiving signals, apparently where they should be on the dial.  
I'll still do a quick alignment, though.  

After taking the video, I let the radio run on my bench for a little over an hour. I felt the main transformer. It did get hot, but not so hot I couldn't keep my hand on it. I will be checking voltages over the next few days, and make any changes or adjustments before I stick it back in the cabinet.  

The record changer restoration will come later. Once I start on that, I will continue the documentation thread here.

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-16-2017

I did notice at odd times, I would get some distortion or rattle from the speaker . I assume it is either an issue in the audio section or could be indicative of it still needing an alignment?
Any ideas or suggestions where to look?

Also, since this has a circuit for the phonograph player, I contemplated adding in a cut-off mini jack to allow an iPod or similar device to be plugged in. My wife enjoys being able to listen to her music or podcasts on the bigger consoles, without having to mess with my AM transmitter. Any thing I should look out for, considering the type of pickup this has and whether this could work without modifying it too much? I'd rather not drill a hole in the chassis, rather, mount a plate with the plug on the back of the cabinet.

There is a switch up on the platform for the record player to switch from radio to phono. I thought I could just wire it in through that connection, and utilize the cut-off feature of a mini headphone jack, which I have on hand. With nothing plugged in, the phono switch would work as normal, and with it plugged in, the phono would be cut off.

Any feedback would be welcome.  

Here's the schematic again for reference.

[Image: https://farm5.staticflickr.com/4320/35910878286_14e1538997_b.jpg]

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RE: 1936 Philco 116PX Electronic Restoration - Radioroslyn - 10-17-2017

> I would get some distortion or rattle from the speaker [Image: http://philcoradio.com/phorum/images/smilies/icon_eh.gif] .

That would be indicative of a loose, torn, or off center cone in terms of a rattle. Distortion could be a number of things. For this check the voltages around the 6A3's, be sure that the grids are at  negative 60v or so. You can check the specs for the tube in the tube manual to determine the correct voltage. Could have a bad cadohm resistor or  driver transformer. Also check the voltages around the 42 tube for starters.

Any thing I should look out for, considering the type of pickup this has and whether this could work without modifying it too much?

My 116X had a phono jack installed before I got it. It disconnects the detector output and connects the alternative input.

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RE: 1936 Philco 116PX Electronic Restoration - Chris h - 10-17-2017

Jeff,
I posted to you on your FB post regarding the speaker rattling. On my 37-116X the green colored adhesive that secures the cone to the speaker basket was flaking off. I used rubber cement to resecure the cone to the basket. Truth be known, there is probably a better way to do this. I sort of looked at the rubber cement as a somewhat temporary fix, as it can be removed. I have two complete radios, and this speaker is from the donner rig, but would like to ask this group what a good permanent repair would be. I would assume an acid free adhesive, but have not yet found one that is good with both paper and steel. Maybe the rubber cement is a good solution, but am open to suggestions.

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-17-2017

(10-17-2017, 01:25 PM)Chris h Wrote:  Jeff,
I posted to you on your FB post regarding the speaker rattling. On my 37-116X the green colored adhesive that secures the cone to the speaker basket was flaking off. I used rubber cement to resecure the cone to the basket. Truth be known, there is probably a better way to do this. I sort of looked at the rubber cement as a somewhat temporary fix, as it can be removed. I have two complete radios, and this speaker is from the donner rig, but would like to ask this group what a good permanent repair would be. I would assume an acid free adhesive, but have not yet found one that is good with both paper and steel. Maybe the rubber cement is a good solution, but am open to suggestions.

I removed the screw and nut holding the spider, and wiggled the spider/cone around. Re-seated the nut and reinstalled and tightened down the screw. It seems to be a lot better. The cone seems to be secured pretty well all around the edge. There's a cardboard washer secured by a series of screws around the perimeter that looks pretty solid, so I don't think that is an issue.

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-18-2017

A new development. When I measured the coils and transformers, specifically, the main TXFR, the secondary was a little off. It now measures 92.5 ohms. It should measure 125 ohms.
I had noted some wax that looks like it came out of the TXFR.
It runs very warm after about an hour or two.
How warm is too warm?
Unfortunately, I can't measure the secondary voltage. Paperwork states it should read 830v on the secondary. My meter won't go that high.
I currently have it running off of my variac at 100v. I also have a bucking TXFR or step-down TXFR that puts out 108v. It still gets very warm, but not as bad as straight from the wall, which is 120v.

Would appreciate some input: Should I consider replacing the main TXFR?

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RE: 1936 Philco 116PX Electronic Restoration - morzh - 10-19-2017

Compare it to a xfmr from a similar radio (similar size xfmr and similar power requirements) while running for the same time. Transformers do get quite warm. But not very hot. However a real turn short (or many turns) will have a noticeable effect on the output voltage: if it is not there, then the xfmr is ok, and you might want to look at the load.

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RE: 1936 Philco 116PX Electronic Restoration - Radioroslyn - 10-19-2017

Mine run a bit warm too. If it keep it on for more than several hour the fan comes on. Line here is about 118v haven't used a bucking trans to lower the input voltage. Because of it's current @ 165w would need about 12v 2A transformer.

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-22-2017

I had been running it with my Variac with it set at 110v, and discovered after measuring, that it was actually putting out 120v at the 110v setting.
I decided to try running it on my step-down or bucking transformer, with outputs 108v. It seems to do OK on that, but still runs hot.
I did run it for about 1 1/2 to 2 hours last night for my annual Radio Show party, and it performed fine , but still very warm.
The record changer and cabinet still need to undergo restoration, so I will probably do an even further investigation into the chassis to make sure I didn't miss something.
I do have a 1936 Philco 116B Early version tombstone, but it also needs a proper servicing. Once it is done, I can run both and compare performance, voltages and heat differences.

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-22-2017

(10-19-2017, 09:01 AM)morzh Wrote:  Compare it to a xfmr from a similar radio (similar size xfmr and similar power requirements) while running for the same time. Transformers do get quite warm. But not very hot. However a real turn short (or many turns) will have a noticeable effect on the output voltage: if it is not there, then the xfmr is ok, and you might want to look at the load.

What kind of difference in output voltages should I be seeing? Running it at 108v out of my bucking transformer, I measured about 725v to the plates of the 5Z3, where the paperwork states it should be 830v. Which seems odd to me. If the resistance of the secondary is low (92.5/125 ohms), I would think the voltage would be higher on the output, not lower.
As a side note, I had forgotten that my step-father gave me his old Micronta analog meter, which is capable of handling 1000v, so I was able to test the secondary output voltage. My digital, I was worried I might top the 750v max and blow it.

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RE: 1936 Philco 116PX Electronic Restoration - Radioroslyn - 10-22-2017

Hi Jeff,
You might want to measure the AC voltage from each of the small pins (plate) to the chassis w/o the 5Z3 in the socket. Voltage should be half of what you see from plate to plate + the 400 ohm tapped bias resistor. The important part is that the two voltage (from each plate to chassis) are pretty equal by a few volts. If you have a large difference then I would be thinking about a PT.

By measuring the resistance of the winding from the center to each end doesn't tell you much as one side is always longer than the other.

GL

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RE: 1936 Philco 116PX Electronic Restoration - PhilcoPhan1936 - 10-22-2017

(10-22-2017, 05:58 PM)Radioroslyn Wrote:  Hi Jeff,
You might want to measure the AC voltage from each of the small pins (plate) to the chassis w/o the 5Z3 in the socket. Voltage should be half of what you see from plate to plate + the 400 ohm tapped bias resistor. The important part is that the two voltage (from each plate to chassis) are pretty equal by a few volts. If you have a large difference then I would be think about a PT.

By measuring the resistance of the winding from the center to each end doesn't tell you much as one side is always longer than the other.

GL

Thanks, I'll try that out. It might be a a bit of time before I have time to pull the chassis and run that test. I'll post back here when I do.

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