philips: LD452AB ; UKW-Koffersuper or other tube based Annette

The "ferrite rod" and coils was missing, but central connection strip/saddle remains.
Looking at rear, there are 3 connections:
a) is both connected S21 and S22
b) is other end of S21
c) is other end of S22
Which of S21 and S22 is LW and which is MW?
From rear on the three connections, left to right, which is a, b and c?
What is total inductance of S21, it is in two parts?
What is total inductance of S22, it is in two parts?

Is the spacing of the two parts of S21 to adjust inductance? Similarly for S22?

I obtained 200mm ferrite rod and glued on a 33mm section so the rod is 233mm and fits on bracket. It may of course not be same permability.

In the absence of other information I will try a few very old  MW and LW transistor radio coils on the large ferrite rod.

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Dear Colleagues,

I found this on the LD480 Annette page

 

Which side is LW and which side is MW?

Inductances?

 

Thanks,

Michael

 

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Dear Michael,

please have a look at the documentation for LX452AB which should be the 'same' model for the dutch market I didn't check too deeply, but it looks good.

There is a complete service documentation in Dutch here (PDF deep link).

Hope that helps,
Mark

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I had to replace the missing AM cord and found the RMorg drawing didn't work. After watch the drum wind / unwind I figured the correct winding on tuning cap drum.

Anyhow, page 9 of that link has the correct lacing for the AM cord.

Incidently I found that a red plastic covered steel paper clip "opened out" made an excellent replacement AM dial pointer/needle.

The S21, S21', S22, S22' are only part number. But now I have the value of AM RF tuning capacitor (9 to 498) and thus can calculate the coils by taking LF end of LW and MW band.

I will wind 30 turns on ferrite and measure the inductance and thus have the Permability at a few MHz (the test frequency of my PIC based tester) and also measure it on a meter that uses kHz (it does 20H max).

Then I can put the permabitily into the coil winding program. I'll just make S21 = S21' and S22 = S22' as they look similar. Infinitly far apart the inductance will be double with two indentical coils in series. Up close forming a single coil the inductance is quadrupled as N squared would apply as if a single coil. So that is how S21 and S22 are adjusted to set LF end of band. The padding capacitors set HF end.

Thanks Mark.

 

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Due to obtaining an LD480AB (rod broken in transit) I can measure the coils S21, S21', S22, S22'

S21 + S21'

In air well separated  10.6uH (likely close to 5uH each as there isn't much coupling.
At max separation on Ferrite Rod* 177uH
Formers Touching on Rod 245uH

S22, S22'

In air well separated  146uH (likely close to 72uH each as there isn't much coupling.
At max separation on Ferrite Rod* 2.2mH
Formers Touching on Rod 2.7mH

 

*Ferrite Rod

I used Ukraine sourced Russian NOS Military 200mm rods. A bit short so lengthened by contact adhesive and a cut broken piece. to fit original holder. The original rod is about 235mm.

 

The LD480 RF on MW "peaked up" well at LF end of band varying S21, S21' spacing and similarly for LW  using S22 and S22' spacing. The two trimmers near volume and tone adjust HF end of band tracking  (MW first and LW (nearer end of set) trimmer second). Thus I'm confident now of replacing the missing coils for the the LD452AB.

 

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