Mende: MS172-W (172W);

Greetings!

I have one of these Mende 172W radios in which the speaker has been disconnected.  I am having trouble understanding the connections to the field coil.

There are 4 connections and four wires going to the field.

In the picture below, I have numbered the connections.

Between 1 and 2, I measure. 3.4 K ohms.  Also 3.4 K ohms between points 3 and 4. So it seems that there are 2 windings in the field. There is no connection between the 2 fields.

Between points 5 and 6 measures 600 ohms, so that is the primary of the speaker transformer. No problem there.

Can anyone explain to me why there are these 2 fields and how they should be connected up? The schematic diagram gives a measurement of 1500 Ohms for the field.

Is it that the fields should be connected in parallel?

Sorry, but my German is not quite good enough to explain this problem.

Thanks

Peter

 

Attachments:

• Mende speaker (118 KB)
• Mende speaker 1 (119 KB)

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Hi

If they could send a photo of the output transformer, seen from below? There should be 3 connections. Two for speaking coil, on the compensation winding against hum. This compensation winding is located next to the field winding. The field winding has in my device an internal resistance of 1493 ohm dc. There is only one winding for field.

Jörg Sigg

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Hi Jörg

Thanks for the reply.  The speaker on my radio has no hum reduction coil. I'm sure, now that it is a replacement speaker, not the original.

Peter

Attachments:

• Mende speaker transformer (139 KB)

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