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nordmende: Nordmende Othello Stereo 3/616

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Forum » Radios and other type of sets (Physics) etc. » RADIO MODELS DISPLAYED » nordmende: Nordmende Othello Stereo 3/616
           
Maurice De Wilde
 
 
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01.May.17 08:02
Reply  |  You aren't logged in. (Guest)   1 I had a look at your collection of Nordmende Othello Stereo 3/616.My remark is The picture shows a Nordmende Othello 3/616.However all the schematics,PCB layouts and the rest refer to a Nordmende Tannhauser 4/633. The Nordmende Othello Stereo schematic looks similar to the Nordmende Tannhauser however the Othello has EL84 final tubes or Roehren.The Tannhauser has ECLL800 final audio tubes. I have both the Nordmende Tannhauser Stereo and the Nordmende Othello Stereo.As I was adding a pre made Stereo decoder to the Othello,I was looking for the 1800 pf preemphasis capacitor and could not find it. In closing ,on the Radio Museum data ,only the picture of the Nordmende Othello is correct,the rest refer to the Nordmende Tannhauser Stereo. Maurice De Wilde
Wolfgang Bauer
Wolfgang Bauer
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01.May.17 10:57
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Hello Maurice,
since everything is all right.
All wiring diagrams are correct
C135 / 1800pF is in the shielding cup, see it in the picture.

Please make a picture of the model/name plate that shows D320 and upload it to the model.

Regards WB.

Maurice De Wilde
 
 
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02.May.17 03:18
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Wolfgang

Thanks for your reply.Any idea  how to remove the can of the Second  IF  transformer(Ubertrager) where the C135 is..

 

Thanks

Maurice De Wilde 

Wolfgang Bauer
Wolfgang Bauer
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03.May.17 09:43
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Hello Maurice,

Why do you want to open the can?  It is fixed soldered.
You will find the soldering spot for C135 on the bottom.
Look at the picture.

Regards WB.

Maurice De Wilde
 
 
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03.May.17 11:01
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Wolfgang

I want    remoce the IF(ZF) can  to remove the 1800pf Deemphasis capacitor as preamble to install  the ready made Stereo decoder  ex Ebay Canada,it is forwarded from China.I have  made now a 12 volt power supply with a LM7812 IC regulator..For the stereo decoder  to work properly,this 1800PF  capacitor has to be removed.I had a look at the Undewrside of receiver.The IF can  has 1 or 2  lugs that are twisted and soldered.It means  using a 30 watt or more soldering iron,heath up solder  very quickly and at same time twist the lug to make it straight,then when  this is done warm  lug again and slightly  move the can  on the side where the lug has been warmed up.it is an operation where you need 10 hands.Then repeat for the other lug.Can should come off to remove 1800pf capacitor.This operation  is not something  that you should  do in an instant.it has to be thought over.

This Nordmende radio,I got from Ebay Germany  for Euro 26,to ship to West Australia,I wrote to the seller in German,usually when  you ask the seller in their own language they are more willingly to sent it to far places.One other seller wrote me "Es ist nicht gerade um die Ecke".

This radio was offered as defect for a "Baestler".Once here I checked on a lower mains voltage,The HT voltage was  200 volt ,should normaly be 280.Out goes the Selenium rectifier,in goes 4 1N 5408  1000 volt 3amp rectifier diodes.Added 150ohm 5 watt resistor to bring the HT voltage down to about 285 volt.The common Cathode resistor  of the two EL85   final penthodes was heating up,also the elco  here showed a bulging + side.Drew to mutch currewnt.Culprit,the 2 ERO 10nF  capacitors  going to the grid of the 2 EL85,showed a + voltage on the side of the EL85,sTook caps out,measured with digital multimeter on 1Mohm range.Showed  leakage.I also do not like  a common  cathode resistor for the 2 EL85 final penthodes.

By now everything works OK.

To concxlude I noticed that  the earlier Nordmende radios  showed a better finish of  cabinet.For example,the plastic  buttons for Stereo,,,Bass..Solo..Jazz are surrounded  by a copper/gold colour surround.On the later Tannhauser  CH 4/633  I bought in 1963  in Munich, in the earlier Othello CH 3/616 this has gone.Also the scale  layout  has a  better  finish.

Later non I want to upload the Tannhauser and the finished Othello.

 

Servus 

 

Maurice De Wilde

Maurice De Wilde
 
 
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04.May.17 11:54
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Hello Wolfgang

 

I have now  removed the can of the  2nd IF(ZF) transformer.Was easy ,just heat up one side of the  can lug and twist it to make straight ,then the other side.Removed the 1800pf  capacitor,slide the can back in and resoldered the two tags.Iow  soldered the capacitor  to the removable  9 pin plug  that fits the  socket on the  roght hand side when viewed from the back.This plug shorts the output  coming from the ratio detector and the  left and right  channels  if no stereo detector is connected.I just have to solder the left and right channels  coming from the stereo detector and the input cable  of the stereo detector  to the  removable plug and remove the  shorts on the  plug.

 

Servus

 

Maurice

Wolfgang Bauer
Wolfgang Bauer
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04.May.17 11:58
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Hello Maurice,

OK, you will be reporting how it works.

best regard WB.

Maurice De Wilde
 
 
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05.May.17 03:55
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Wolfgang

 

There must be many Nordmende and other similar  radios that are Stereo ,but only Stereo when  playing  records or tape recorders.For full stereo  you need a stereo decoder.There is a source of decoders,see my attachment.Ocasionally  on Ebay Canada there appear  these decoder,specially made for Valve type radios..The decoders are sent from China.However   you have to be quick  to buy one.It is only from time to time  these decoders come up.I bought three of them.To connect:

 

-Radio has to be  wired for it,thus marked as stereo.

-Deemphasis  capacitor, for Nordmende radios 1800pf capacitor,this one has to be removed.This capacitor is either located inside the  second IF  transformer can or later on  soldered to the  stereo adapter socket usually  for Nordmende radios   on the right hand side  of the radio  seen from the back. 

-You need a 9 to 12 volt DC power supply or a 9 to 12 volt battery.

-Connect the output of the ratio  detector to the input of  the decoder,this socket on the decoder is yellow also marked INPUT.Connect   to pin 4or 5 of the socket of the radio where the decoder is connected to

-Connect right and left audio outputs,sockets,red and white in colour and also marked Right and Left output.Connect these to the  pins 2 and 3 of the socket where the decoder is connected to  on the side of the radio,here Nordmende.

Later on when everything works ,I intend to upload details and pix.

On my Nordmende Tannhauser  radio,this one has a stereo decoder connected,originally was a project of Electronics Australia.Here I expanded by adding a transistor driven relay   that switches on the STEREO  globe on the Nordmende Tannhauser,earlier   stereo  radios  did not have this rtereo  globe.

 

Servus

Maurice  

Attachments:

Maurice De Wilde
 
 
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05.May.17 08:06
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Wolfgang

Hello

 

I have now the Stereo detector ex Ebay Canada connected.I opted for a small  transformer ,output 15 volt 150ma, this gives after the LM7812  regulator 12 volt DC.I mounted the  4 1N4004 diodes and  2000MF 35volt on tags  simply soldered on top of transformer.The transformer is soldered to the side of the radio chasis,that bway I do not drillo any holes on the Nordmende Tannhauser or Orthello.I still have to find a way  to mount the decoder inside the cabinet..Now when you look at the schematic of  the Tannhauser or Othello,they show  the connections for the  socket at the right hand side of the Tannhauser/Othello.It shows 2 connections to connect the  Ratio detector output,either via socket pin 4 or 5.Pin 5 connect the detector output via R134 22Kohm or via pin4 bypassing this resistor.You only do this  when there is not enough outut voltage coming from  the ratio detector.

Also I always get confused on the schematic  of the connection layout of the  socket.On the schematic ,the pin sequence  as shown 1,2,3 etc is actually  when shown   from above the plug is actually 9,8,7 etc.On the stereo decoder I did not had to touch the Separation control.Only the Input    sensitivity I had to adjust.When there is a stereo transmission  the LED on the decoder lights up.

 

I use these Nordmende radios to listen to the audio  coming from   the satellite receiver here via a UKW

Crystal controlled  transmitter.Here nin Australia you can do this  as long that the output is 10Microwatt or less.Enough to go   over a 100 metres far..The Satellite dish is 3 metre with actuator(motor) to turn the  sat dish to 9 satellites.I watch mainly TV from NL-B-F France 24 Monde -TVcinq,they show in the morning CH  RTS tv-SP-PORT- Malaysia tv-Singapore tv- and many more ,also many radio  stations  in stereo.Thus it is a marriage between  vintage technology and newer technology.

 

Servus 

Maurice

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Maurice De Wilde
 
 
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05.May.17 08:11
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Wolfgang 

 

I am  forwarding 2 pix of Othello   with Stereo decoder

 

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rmXorg