Two Nordmende Valve Radio Questions - UK Vintage Radio Repair and Restoration Discussion Forum

Joxtinkerer · 18th Nov 2022, 5:44 pm

So,

I managed to buy my first ever valve radio last week - a Nordmende Turandot F. It was in a pretty dirty condition, full of cobwebs so I took it apart and cleaned the whole thing carefully. Some pics below.

Pots were very sticky and there were some small spots of corrosion here and there.

The fabric front had some liquid splashed on it in the past, so was badly stained. I did a few spot tests on the hidden bit behind the fascia and the winner was vanish foam applied using a q-tip. I've managed to rub off fabric fronts like this in the past with little effort and they're generally not up to anything more than a light clean but the vanish worked without destroying it. Phew. See the results - looks really clean now.

The unit has some really unusual split head screws on the front, made out of copper. Some citric acid crystals cleaned those up so they are a nice colour now, not green! The plastic fascia got a good clean with the novus plastic polisher. Even the light still works.

INVESTIGATIONS
So I can see a couple of faults - Picture x shows the internal FM aerial which has a loop and solder point on the inside top of the case. I see one side has broken, so a dab of solder should fix that.

Next thing I spotted is they've cut the cable (which looks and feels like rubber) incredibly short and whacked a connector block and new mains lead on there. Great for pool parties, not!

AM Aerial is hanging loose and needs remounting - one of the whiskery thin wires running to this was already broken but I haven't broken any others.

I fired it up and like an idiot, expected instantaneous sound. I then realised and waited, there came the noise. The speaker in this unit is really quite exceptional for the age and it's just beautiful, warm and rich to listen to. I love looking at the valves glowing.

QUESTIONS:

I think it's worth replacing the mains cable completely into the unit and soldering it in place. Much safer! I was also wondering, as there's a transformer here, can I run three core and connect the earth somewhere? Is it worth earthing this unit?

Does anyone know where to get those two pronged FM aerial connector headshells? I'd like to connect an external aerial for FM to this unit but would like to do it properly.

Iangebbie · 26th Nov 2022, 6:55 pm

From most of my re builds, I always replace the mains lead with a double insulated type (Outer plastic containing two or three cores) no longer than 5m is the recommended length.
I note that the original mains cable is two core, my approach to this is measure (With the radio off and unplugged) between primary and secondary using a insulation tester (Ohms meter is a second option on high resistance) just to prove there is no leakage between primary and secondary, if Ok hard wire the mains cable and ground the earth to chassis.

As to the rabbit ear VHF antenna, there are two spaced sockets adjacent to the mains selector, look at the back cover to see if one of them is marked FM antenna, if so that's where the external antenna would connect

Good work on the progress you have made, looks good, any questions just post on this site lots of people have had similar problems as yourself

Cheers Ian G

Iangebbie · 28th Nov 2022, 12:44 pm

Just to explain a bit better on the primary secondary bit , your set has a mains transformer with two main windings (There are more for heaters of valves) but lets just take the main windings, in good condition there should be no electrical leakage between the two windings, with the set unplugged but switched on, take a meter to the live of the plug (This in effect ends up on the primary winding) then go inside the set and find the rectifier (Could be Valve or semiconductor) the secondary is connected at this point, you are looking for any leakage between the two, if none then its safe to ground the chassis, as to your issues with the AM antenna leads, normally the thin wire from the ferrite winding is terminated on a soldered sleeve on solder tags, if its still long enough to re-solder to that point, the cable will be insulated with a varnish, the varnish will have to be removed before soldering, try a match and burn 5mm of it off then tin the wire with solder then make the connection, Cheers Ian G

18th Nov 2022, 5:44 pm	#1
Joxtinkerer Diode Join Date: Nov 2022 Location: London, UK. Posts: 9	Two Nordmende Valve Radio Questions So, I managed to buy my first ever valve radio last week - a Nordmende Turandot F. It was in a pretty dirty condition, full of cobwebs so I took it apart and cleaned the whole thing carefully. Some pics below. Pots were very sticky and there were some small spots of corrosion here and there. The fabric front had some liquid splashed on it in the past, so was badly stained. I did a few spot tests on the hidden bit behind the fascia and the winner was vanish foam applied using a q-tip. I've managed to rub off fabric fronts like this in the past with little effort and they're generally not up to anything more than a light clean but the vanish worked without destroying it. Phew. See the results - looks really clean now. The unit has some really unusual split head screws on the front, made out of copper. Some citric acid crystals cleaned those up so they are a nice colour now, not green! The plastic fascia got a good clean with the novus plastic polisher. Even the light still works. INVESTIGATIONS So I can see a couple of faults - Picture x shows the internal FM aerial which has a loop and solder point on the inside top of the case. I see one side has broken, so a dab of solder should fix that. Next thing I spotted is they've cut the cable (which looks and feels like rubber) incredibly short and whacked a connector block and new mains lead on there. Great for pool parties, not! AM Aerial is hanging loose and needs remounting - one of the whiskery thin wires running to this was already broken but I haven't broken any others. I fired it up and like an idiot, expected instantaneous sound. I then realised and waited, there came the noise. The speaker in this unit is really quite exceptional for the age and it's just beautiful, warm and rich to listen to. I love looking at the valves glowing. QUESTIONS: I think it's worth replacing the mains cable completely into the unit and soldering it in place. Much safer! I was also wondering, as there's a transformer here, can I run three core and connect the earth somewhere? Is it worth earthing this unit? Does anyone know where to get those two pronged FM aerial connector headshells? I'd like to connect an external aerial for FM to this unit but would like to do it properly. Attached Thumbnails

26th Nov 2022, 6:55 pm	#2
Iangebbie Tetrode Join Date: Oct 2013 Location: Alconbury, Cambridgeshire, UK. Posts: 87	Re: Two Nordmende Valve Radio Questions From most of my re builds, I always replace the mains lead with a double insulated type (Outer plastic containing two or three cores) no longer than 5m is the recommended length. I note that the original mains cable is two core, my approach to this is measure (With the radio off and unplugged) between primary and secondary using a insulation tester (Ohms meter is a second option on high resistance) just to prove there is no leakage between primary and secondary, if Ok hard wire the mains cable and ground the earth to chassis. As to the rabbit ear VHF antenna, there are two spaced sockets adjacent to the mains selector, look at the back cover to see if one of them is marked FM antenna, if so that's where the external antenna would connect Good work on the progress you have made, looks good, any questions just post on this site lots of people have had similar problems as yourself Cheers Ian G

28th Nov 2022, 12:44 pm	#3
Iangebbie Tetrode Join Date: Oct 2013 Location: Alconbury, Cambridgeshire, UK. Posts: 87	Re: Two Nordmende Valve Radio Questions Just to explain a bit better on the primary secondary bit , your set has a mains transformer with two main windings (There are more for heaters of valves) but lets just take the main windings, in good condition there should be no electrical leakage between the two windings, with the set unplugged but switched on, take a meter to the live of the plug (This in effect ends up on the primary winding) then go inside the set and find the rectifier (Could be Valve or semiconductor) the secondary is connected at this point, you are looking for any leakage between the two, if none then its safe to ground the chassis, as to your issues with the AM antenna leads, normally the thin wire from the ferrite winding is terminated on a soldered sleeve on solder tags, if its still long enough to re-solder to that point, the cable will be insulated with a varnish, the varnish will have to be removed before soldering, try a match and burn 5mm of it off then tin the wire with solder then make the connection, Cheers Ian G