Our radio has found her voice. Power and Audio testing. Nordmende Super 250-9 rest. pt. 2
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- Опубліковано 16 вер 2024
- As was obvious from the first video, the audio level on this Nordmende Super 250-9 was disappointingly low. I was afraid the problem may have been the output tube, an EL41, which I had no replacement for, but fortunately that was not the case.
So, onwards as per my usual modus operandi: First the power supply, then the audio section.
My goal for this stage of the process was to get the audio section restored and tested, and that is what is covered in this video.
Hope you enjoy it.
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#tuberadios #antiqueradio #radiorestoration
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Great video! And the first time I actually see someone giving a reference voltage level for the pickup input and the speaker output. This might seem obvious for many, but for people starting with tube radio repair, that type of info is very helpful! I remember when I started with this, I had no clue what level to put on the input or expect at the output.
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Always learning something from your videos.Thanks for the efforts.Greetings from Vienna Austria
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As usual, another video worth watching. Thank You
pleasure
Electronics old and new your utube videos are awesome
thanks
*THUMBS-UP* as always!
thanks
I like this set, unlike many of NordMende's later products. When I was an apprentice TV engineer back in the '80s I had to work on their portable TVs - they had been modified to work on UK mains, which involved a transformer and a few dropper resistors (they didn't natively have the multiple voltage selection like this radio). They were very unreliable and a nightmare to work on. I think everything was overdriven by the power supply causing random things to fail. Keeping one going was like spinning plates. It's a shame that happened because I think NordMende normally made quality kit.
a their 50s radios were certainly built to a very high standard. Some accountants must have stepped in later 😊
Electronics old and new your NordMeNde super 250_9 shortwave radio Receiver is cool
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I use a Weller 250 watt soldering gun and a piece of 12 gauge wire as a tip for chassis soldering. Mr Carlson showed this On a video a long time ago. He recommended the older guns but I got a new one cheap and it’s fine. I did require trigger because for some reason Weller had it so reduced power was when the trigger was fully depressed and full power when 1/2. That makes it painful to use when you want a lot of dwell time. The use of wire means it’s cheap to replace and you can bend it to custom shapes
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@@electronicsoldandnew ‘rewire the trigger’ (typo)
Nice job 👍
thanks
Thanks!
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LOL!..."these are makeup removers...which I don't use...".....RIIIGHT!!! 🤣
You’ve discovered my dark secret 😊
About being "bass heavy ". Keep in mind the acoustic bafflestep. At a certain point radios were starting to implement correction for that in their feedback circuits.
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Another good video =)
I have a question if you have a moment of time. I'm finally getting around fixing up this ole Airline 1814A. Not a complex radio at all (one of the reasons that I chose it). Looking at the schematic I have found a disparity. On 2 voltage supplies there is C1A/B. Inside the can, on the radio now, (this very much looks like an original part) there are 100, 50 mfd caps, the schematic shows an 80, 80. Do you think it really matters all that much? Would you stick with 100,50 or chose a couple 80mfd caps?
From what I've managed to learn, I don't think it will matter all that much, but I also have a feeling that this may have been a change because one of the voltage supplies needed the extra capacitance.
You’ll have a really hard time finding 80uF caps. I’d go with the 100/50.
Well done. The mains transformer tap appeared to be still in the 220V position, though this probably doesn't matter whilst on the dim bulb, I wondered whether the B+ was now higher with the replacement rectifier.
Yes, the dim-bulb will stay in action for now. The B+ did go up quite a bit.
Greetings:
I forgot whether you have a source of a 20Hz - 20kHz audio sweep. If you have that capability, how about showing it to display the amplifiers frequency response when you set the tone controls for minimum change and show how the different tone modification settings affect the output.
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"... uh my favorite tool", Re-purpose of chopsticks very innovative great named too ha ha
It was chosen on purpose. Wondered if you’d pick it up 😊
@@electronicsoldandnew Revenge is sweet, after me teasing you about your chopsticks
I like your sense of humor, besides learning about German radios
😊 And I have absolute deniability: my nickname to some is “MAC” as these are in fact my initials. But if you listen carefully, I definitely put in a hard “k” at the end 😊
L48 and C96 should cut the 9 kHz whistle in AM. Some German radios of that period have that filter.
Thanks. Just learnt something new 😊
Nice explanation again! Can we call that on 10:28 as a Pi filter? Thanks.
Yes it is.
I was wondering if i could order some guitar to tube radio interface boards. I recall you had planned to make the gerber files available. I missed the boat somehow.
I’m away on holiday for a couple of weeks, but if you remind me after that, I’ll see if I can send the Gerbers for you.
Boa Tarde , Manuel.
Estou também a ver se mudo o meu rectificador de selénio. Deveria ter 285v no B+ mas tenho apenas 255. Vou usar 4 diodos 1n4007. Vi que o seu rádio o b+ é 280v. Foi necessário usar alguma resistência para baixar a voltagem saida do rectificador?
não, não foi.
@@electronicsoldandnew obrigado 👍
i was wondering if it´s a good idea to connect the green yellow earth to the chassis.... for several reasons, but one of them is you are inviting static noise from your "dirty" earth-line in the house into the receiver.
it’s always a good idea for safety reasons. In fact, if I’m not mistaken, in many countries this has become an obligatory connection. Line noise is always an issue, and I’ve certainly had my share of it, even when not connecting earth to chassis. I’ve experimented with capacitor filters on the mains but as yet haven’t found the perfect one.
@@electronicsoldandnew
Hi Mr. Caldeira, you are completly Right about security. But be aware you are connecting the radio Antenne Earth to the protective conductor.. how do you connect L M K Antenne in terms of earting ?
Ground Loop? Btw i love your movies 😉
Let me make a confession: The radios that I am going to use personally don’t normally get connected to mains earth. If I think someone else is going to use them, I connect the earth. I fear that someone may get zapped and I’ll feel the guilt 😊 I’d rather they get a little noise than a shock.
I noticed that there are differences on the schematic as regards depiction of resistors. Some have an “X”, some have a “/“, some appear to have a “=“ sign across the middle, and some are just empty rectangles. I’m not familiar with this convention. Can you enlighten me as to the significance of the different designations?
These give the power rating of the resistor, which is usually shown on the service manual (usually on the schematic sheets itself).
Thanks! I’ve not seen that before. Must be a Dutch or European convention. (We don’t see that many European radios over here…)
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I miss the pile of cotton swabs :)
Save the planet 😊
Ok ok, I'll stop the rant :)
No, keep it up, I love a good “despique” 😊
Portuguese made power cable?
MaxMat special 😊
Can you transfer the smell of a failing overheating Selenium Rectifier to your audience?
When youtube adds sensory functions, sure 😊