[Ron Ramirez]

Okay!

Nichicon CS electrolytics ordered from Mouser (which should fit inside the paper tubes). Flocking fibers ordered via eBay. Now it's a waiting game. I will attempt to rewind that burnt coil winding today or tomorrow.

[morzh]

I found out that when I heat the cap (I do it on Low) the wax melts and you can wipe it out without any mineral spirits.

then again, I might choose to keep some dirt just for looks.
Like in jeep Grand Cherokee commercial.

[Ron Ramirez]

That's what I was doing - heating the caps until the wax melted, pulling out the innards, then quickly wiping the shells off with a paper towel before the wax hardened again.

[Ron Ramirez]

AM primary of the antenna coil is now rewound...

[Image: http://www.philcoradio.com/images/phorum...e00009.jpg]

Not the neatest job, but it should work since this is merely the primary of the AM antenna coil.

It is 350 turns of 38 gauge wire. The original resistance of this winding, according to the schematic, is 33 ohms. This one is measuring 28 ohms, close enough.

I checked the resistance of the other windings and they are all OK.

I'll reinstall it in a bit, and replace some more wires while I am at it.

[morzh]

Same exact way i rewound the burnt antenna coil in the Emerson I restored a year ago.
Worked like a charm.

[klondike98]

I need to rewind one on a Warwick as I haven't found a replacement but don't think I'll be able to count the # of turns on the existing one as its fried to a crisp.  Did you guys just estimate the turns or go by resistance?? Thanks!! (I just checked the schematic and it doesn't have a resistance value on it...so a rewind will be all estimation I think).

[Ron Ramirez]

Bob

I just posted a suggestion for you in your Warwick thread.

In the case of the 42-720 coil, I was able to unwind most of the windings of the AM antenna coil primary, so I could make a fairly close estimate of the total number of turns.

I was going to get out my micrometer and measure the size of the old wire, but as usual for me, I was so focused on rewinding the coil that I forgot. The original may have been 39 gauge since the total resistance ended up a bit off, but the coil should still work as the antenna primary isn't as critical as, for example, one of the oscillator coils.

If this set had been AM only, or if this coil had been only for the AM band, I would not have hesitated to try a P-C70-A universal antenna coil from Antique Electronic Supply.

[klondike98]

Thank you Ron!

[Ron Ramirez]

No problem, Bob.

I've reinstalled the antenna coil, replaced three of four wires which go between it and the band switch, had to resleeve the fourth wire with heat shrink tubing since I could not get to that particular band switch terminal with my soldering iron.

A few more wires to replace and then...waiting for the electrolytics...

[Ron Ramirez]

Review: Here is how the underneath of the chassis looked before I began working on this set:

[Image: http://www.philcoradio.com/images/phorum...e00002.jpg]

And here is how it looks now:

[Image: http://www.philcoradio.com/images/phorum...e00010.jpg]

I've replaced every wire that I could reach. A few wires in the vicinity of the band switch received color-coded heat shrink tubing as I was not able to reach both ends of those wires with a soldering iron without risking damage to a coil or other wires in the process. Three rubber-covered wires remain; these three connect to ground and even if the dried out rubber falls off, they are not touching anything else and should be OK.

Here's the antenna coil which I rewound the AM primary winding on, back in place on top of the chassis:

[Image: http://www.philcoradio.com/images/phorum...e00012.jpg]

I've even replaced the resistor (29) and capacitor (30) which connect between the volume control loudness tap and ground. Here is a difference between the 42-724 and the 42-720: In the 724, this combination is 10K ohms and 0.1 uF. In the 720, it was 22K and .02 uF. The replacements are 22K and .022 uF inside the original .02 uF sleeve.

[Image: http://www.philcoradio.com/images/phorum...e00014.jpg]

You will note the grounded end of (30) is not yet connected to the solder lug. This is because that lug is on the back of the dial scale backing plate, and that will have to be removed, painted, and re-flocked once the flocking material gets here.

See how rough the backing plate is:

[Image: http://www.philcoradio.com/images/phorum...e00016.jpg]

Well, folks, that's it for now until the electrolytics and flocking fibers arrive.

[morzh]

Bob

When I looked at Emerson I estimated it was 250 turns.
When I counted the turns, it came out at 270. Not bad for an estimate

I think you should still try to count turns.
What's burnt is the enamel, the wire is still there and can be unwound and counted just fine.
Just be gentle as the copper becomes soft and tears apart easily.

[NostalgiaRadioTime]

Looks great, Ron!   Coming along very nicely.

Noticed that dial back plate waiting for reflocking on your set almost looks identical to the one on my 42-345T. Luckily that one was in nice shape, still retaining all of its chocolate brown flocking. There were a few faded spots from where light showed through the dial scale, so to even out the color, I used some dark brown spray paint that was pretty darn close to the color. Just sprayed some on a shop towel and wiped on a very light coat. Blended in perfectly.

[Ron Ramirez]

Well, there's good news and bad news, folks.

What shall I give you first?

Okay, the good news:

The capacitor order arrived today. I immediately opened the box and pulled the caps I needed to restuff the two electrolytics:

[Image: http://www.philcoradio.com/images/phorum...e00017.jpg]

I had already attached antenna and ground leads and an AC cord.

After electrolytic installation, I tested all six tubes. Two were bad.

A 7B7E tested dead...and the dreaded 6X5 had P-K shorts!

[Image: http://www.philcoradio.com/images/phorum...e00019.jpg]

Imagine that, a Brand Z 6X5, at that.

I had good, tested spares for each, and these were installed.

Once these were in place, the set was turned on...and it came to life:

[Image: http://www.philcoradio.com/images/phorum...e00018.jpg]

It was barely picking anything up; the strongest signal was my SSTRAN signal which came through loud and clear.

So far so good, right? (You can probably guess where this is going.)

Now the bad news.

After playing for about a half-hour's time, as I sat in my easy chair across the basement from the workbench, it seemed to me that the volume began to drop slightly.

I looked - and the power transformer was releasing its magic smoke!

 

I did consider snapping a quick photo, but I was more concerned about preventing a possible fire and with keeping the work I had done from completely self-destructing.

Naturally, the smoke release made the area where my workbench is smell awful...and the transformer was extremely hot...liquid wax was pouring out of it...

So this one will require a power transformer. That means that, once it cools off, it will be put back on the shelf for awhile.

But at least I have the satisfaction of knowing my AM antenna coil rewind worked, and I also know that the radio will probably play fine with a new power transformer and a good alignment.

[morzh]

Ron


Are you sure it is the transformer?
The way you described it, it could be something else.

[Ron Ramirez]

Oh, it was the power transformer, alright. You should have seen the smoke coming off that sucker...And it is HOT HOT HOT. The wax inside the transformer melted and was coming out.

I think when the Brand Z 6X5 shorted out, the damage was done. Then I come along, buy the set and try to get it going again...My guess is that the 6X5 short caused windings in the power tranny to partially short, and it couldn't handle the stress of normal usage after I put in the good 6X5 tube.