The loop antenna is hidden in a cut corners square box.




Removing the 16 screws of the cover plate, we discover the winding:
20 turns, which average area is about 480 sq. cm. (75 sq.inch)




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It is also noteworthy that there are 3 contacts:
-- one at the top : the end of winding, which is linked to higher peak.
-- one at the bottom, on the axis: the beginning of the coil, connected to the lower peak.
-- another at the bottom, connected to 2 pins: a tap at 1.5 turns from the end of the coil.
Only 2 contacts are used, connected at the hinges of the door.




The 2 peaks are used to hang the antenna to the rear of cabinet (notches A1 and A2).
In this case, the entire winding is used, but when the loop installed in the door, across the hinges winding used includes 1 lap and a half less (probably to compensate the length of the wires?)

The central contact, bowl-shaped, touches the central plot of the door which is connected to the lower hinge;
The 2 peaked contacts touch the circular contact of the door connected to the hinge between.

No contacts through the hinge higher.

It should be scrupulously check these contacts, in particular the wires are practiced in grooves in the wood of the door, hidden by wax.
The hinges themselves include spring of threads that connect electrically the 2 parts that are moving one to the other.

The measure of the inductor of the loop antenna gave 115 µH, the capacity approximately 40 pF.
With the varcap at 660pF maxi, this will give a minimum frequency about 560kHz, i.e. a wavelength about 535 meters.

  The loop antenna


All the metallic components of the loop and the door must be removed and cleaned (acid, polish, steel wool ...)




I took the opportunity to redo the contacts of the hinges. Simply put unsolder-braid around the axis and solder each end on each part of the hinge.
We must do a turn and a half of braid, and does it in the open position of the hinge. Thus, when it closes, the braid is a little longer, but does not block the closure.







I took the opportunity also to redo the notch lock of the door: a screw was missing, and the use was such that the remaining screw was not fixed.
On the other hand, we see clearly that the 2 screws crossed the wood.
So I rebuild 2 screws (by cutting 2 new screws at suitable length), and I put the plate on a thickness of wood cement, so it is better hanged.




This wood cement must be tinted to be invisible.

Then I glued a small piece of veneer on the box (wood glue)
Just then sanding the wooden parts and eventually ending with steel wool; a layer of satin varnish will finish the antenna and door restoring.
When the varnish is dry, metal parts must be reassemblied, especially the hinges that must be soldered with wires links (below).

During the removal, I was able to measure its resistance about 2000 ohms and I had concluded that it was ok.

So I wanted to check it with the help of a generator, and then, surprise: nothing !

By measuring its resistance again, I find infinity value! And the cause is there, obvious: at the release of connections, I had to force, and one of the 2 bolts runs free, in other words, I cut the internal wire connection!

I have to disassembly the motor ...
First I removed the 2 shocks, which are in fact made up of 2 rubber discs each, and a big washer is sandwiched and connected to the body of HS with a rod.










The third shock has no washer, the rod welded on the ear that comes through one of the rubber discs.
The discs are about 6 mm thick with a diameter of 38 mm. (1"1/2)
The best thing is to do new discs in silicone rubber.
The motor is screwed on the ear, 2 fiber seals are interposed.




To disassemble the motor, I see only one solution: unscrew the body which is made up of 2 parts.
Unfortunately, the first attempt was unsuccessful: seizure!
So I leave the junction of 2 parts in the dégrippant some time ...
So I tried again using a key filter:




Nothing to do! I have forced with this key, the motor caught in a vise, everything is blocked.
So I tried to screw 2 bolts, in order, with a metal bar, to make a kind of key:




And this is the result: the aluminium smelter did not resist!




So I decided to open ... For this, I use a diamond disc on a mini-drill:




As I do not know how are disposed internal organs, I go in a haphazard manner; I cut arcs:







Always hoping to be able to run the whole, but there is nothing!
I go on ...
And ultimately, I reach the wiring connections of the coils:




Thinking bad contacts are located on the 2 pods, I decided to solder 2 brass screws.
And in fact, doing this, I get the 2000 ohm again, whew!
The reassembly is quite simple: I glue the pieces with cyanoacrylate glue.




And I filled sawing straits with automobile mastic.
I checked the resistance: horror, I always have bad contact! Unbelievable ....
I desassemble again, but only on the screws side:




I saw another piece to discover the other side of the pods:




And there, I can see that the contact is made with a soldering rivet. We should not look any further, the bad contact is here!
I solder the 2 rivets, the contact is restored.
I reassemble all pieces. Here is the motor repaired:




I measure the resistance one more time: ok.

Two hours later, I measure the resistance: cut again! groar !
I do not understand anything. Or the problem is simply one of the coils to be intermittently cut ...
I make this test: I tune a power supply for 100V and I put contact on the coil. By doing so, I hope to provoke a small electrical sparkle at the wrong contact and perhaps a mini welding will be made ...
And it works: The contact is restored !

I will still monitor the motor of this horn speaker: I now know that it may cause me trouble. In any case, this is not the fact of having unscrew the 2 wires that caused this bad contact, I think it was inevitable.
Well, if the problem recurs, it will be necessary that I decided to completely dismantle the motor to gain access to the coils, to be repaired.
So, to be continued ...

The cabinet of this set is plywood made. It suffered from moisture, the veneer comes off on the top and on the high sides.
The rest is in a much better condition, just a little off, but no more.
To redo the cabinet, remove everything:
Handle anchors




And the inside reinforcement wich is attached to the sides




Tapped legs for fixing chassis




Contacts rear antenna (A1 and A2)




The lock of the rear door




And the batteries support and connector.

Here is the naked cabinet, ready to be renovated:
View from the front (at the top :radio chassis compartment , at the bottom: horn speaker compartment)




The right side




The rear (battery compartment)




The left side




The underside (I left foot metal)




And the top





A) Repairing the top of the cabinet
The top veneer can already be removed completely, it does virtually over.




Discovered on the 2° layer of veneer with some material lacks.





The first step is to paste the remaining pieces on the intermediate layer.
Pliers and weights maintain pieces under pressure during glue harding:




Then fill the lacks by sticking cardboard 1 mm thick. Just cut out the shapes of the lacks keeping few millimeters joints.




A stroke of plane may be necessary to remove the lumps:




When the wood glue is dry (about a half of hour), we can use mastic to fill the interstices of pulp wood.




It must be very dry to be able to sand.




Thus, the surface is sufficiently corrected in order to receive the veneer.




I used thermofusible veneer. We must cut a piece slightly larger than the top (1 or 2 cm more)
Then it must be positioned in such a way that a good side is on the front.




Normally, this veneer sticks with an iron, but the heat fan is more speedy!




First, paste a side, and then moves on the heater to the other side.
I press with the hand with a rag to the heated place.
When everything is stuck, it is necessary to cut the overruns with cutter on the reverse side of the veneer,laying it on a hard surface.
This is what we obtain:




View from the corner:




Then we have to cut the 2 circles for the passage of the handle.
First, I spotted the axes: they were strictly on the median in length and at 94 mm from the edge.
2 small crosses indicate centres




Cutter is used, from the center to meet the board.
You must make sure that the support fits well




Those are the 2 cuts made:




The next day, it shall be ensured that the veneer is no bubble. Indeed, after a cooling time, it does happen.
It is sufficient then to heat again locally and highly press.
During one day, we have to check several times and it was only after 48 hours that is safe for work.
It is better to lose a little time at this level, than be forced to heat again once varnish is applied!


B) Repairaing the sides
The sides are damaged on the top:




The veneer is off, but all can be kept.




It is therefore necessary to make pieces of veneer to fill in the lacks.
Just take the form by putting a sheet of paper on the lack and coloring with a pencil:




Then, with a cutter, you mark the veneer using the form on paper.
The veneer is cut with scissors, and properly adjusted to fit the lack




When the form is good, it can be glued.




There are still some lacks that need to be filled with the pulp wood




Once the sanding done, we ca see the connections parts, but really a little.





C) repairing the rest of the cabinet.

The rest is not too damaged. There are a few places where the veneer comes off a little.
Some pieces of wood should also be replaced (tassels, partition ...)
The pasting is done with wood glue, the press is improvised, it is good to keep transformers ...







The corners are also off. For glue them, clamps are needed




The partition is reglued also, just put transformers for pressing:





The rear door is not too damaged, just a few scratches.




Its internal side is just dirty, it needs to use lightly steel wool.
Be careful not to break the label metal nor glued one.




The renovation is to lightly sanding the outside, insisting on scratches to attenuate them.
Two layers of varnish is enough: the first is wild cherry, the second is medium oak.

The grid of HS is a little more damaged: one corner is broken and twisted.




In addition, the canvas is ripped at 2 places, including a very visible one. It is also very dirty.




The plywood plate must be re-adjusted and re-glued. For this, it is necessary to dry the glue under pressure, against a metal plate.




The canvas should be depasted from the board. It goes easily, but we must still be careful not to rip more.




Once washed, it must dry flat on a sheet of paper.
Unfortunately, in general, when washing this type of canvas, it shrinks, and then, the piece is 2 cm shorter!
So, it would be better to change the canvas.
The original canvas is unprinted, but we can try to use canvases with drawings, or with different colours:




And the result can be pretty...
Anyway, it's really a detail you can always change later.
Simply paste the canvas at the back of the grid, only on the edges(like this, it may be easier to remove it!)


D) finish

When the veneering and filling are finished, we must now varnish.
First we must sand the entire surface with fine sandpaper, then with steel wool.
The first layer of varnish, wild cherry tint, is applied with brush.
The drying time between layers is to be met.
Here is the cabinet, front viewed:




Remember varnishing 1 cm back inside, because the chassis and the grid of HS are set back from the edge.




Tint is not quite the same as the original, there's the antenna door positioned near the cabinet for comparison:




However, the tints are close:




A second layer of the same color will surely darken.

It must be sanded again with steel wool before applying the second layer.
Finally, a third layer, medium oak, will get almost the same tint as the original.