Tube Radio Selenium Rectifier and Filter Cap PCB's. Sometimes you just don't need the Full Monty.

[@f.k.burnham8491]

Some folks are not aware that the current carrying capacity of a diode is measured with full length leads. They act as part of the heat dissipation. We discovered this when the organ repairman kept blowing ECG diodes in a bridge. A call to the ECG engineering dept. provided this information. He just curled the leads and mounted them a bit higher off the board and it worked like gangbusters.

[@electronicsoldandnew]

👍

[@DavidTipton101]

Nice idea Manuel. PCBWay is very reasonably priced even the shipping to Oz was surprisingly good. Thanks for another great video 👍🙂

[@electronicsoldandnew]

pleasure

[@xyredmax]

Such a simple idea but a truly brilliant solution - Thank you

[@electronicsoldandnew]

You're very welcome!

[@paulbennell3313]

Beautifully simple, very neat and solves several problems at once! And no need to dig horrible gunk out of old capacitor cans if you aren't in the mood for it.

[@electronicsoldandnew]

👍

[@lelandclayton5462]

I've seen Cap PCBs from time to time such as the Adapt a cap and silicon diode packs that replace tube rectifiers. I also remember seeing a guide where you can make a Cap can replacement for stuffed caps using a old toilet paper roll. I really like the Selenium replacement board since it has the Resistors.

[@electronicsoldandnew]

👍

[@mackfisher4487]

Slick and particularly a neat idea from the "German Radio Restoration Guru". Museum quality restoration versus quality restoration, I understand a collector wanting to have a museum quality restoration re-stuffing capacitors and doing whatever is necessary so that a person when he looks at the final product can't tell that any work has been done it looks new or close to it. However, as most of the parts that need to be replaced are under the chassis and thus out site except when out of the cabinet it should not make much difference to the majority of the hobbyists.

[@electronicsoldandnew]

I agree. I’m generally keen to “keep it original”, but sometimes I wonder if it warrants it. Especially as the originals are left in place (unconnected) so you can always re-do it if so desired.

[@hestheMaster]

Great idea for non American made radios you work on Manuel. There are some US made radios than can benefit from the rectangular PC board where the Selenium rectifier will be replaced by a Silicon diode and power resistor . The round PC board can be used where two electrolytic caps are commonly found and the original can be left in place while the new round PC board can be used to replace the old connections above the old . Not into restuffing electrolytic capacitors, so this repair can be easily done. That being all said, I have a lot of terminal strips that I use to do this repair. But this would all look so MUCH neater using them! Nice demo too!

[@electronicsoldandnew]

thanks

[@markpennington9429]

Simple, brilliant. Just ordered some.

[@electronicsoldandnew]

👍

[@I967]

What a neat idea! Thank you for sharing!

[@electronicsoldandnew]

pleasure

[@danielsaturnino5715]

Oh my god, a pcb inside a vintage tube radio :) people will start a riot. Thanks for the video :) PS serious question. I thought a selenium rectifier worked as a single diode? Thanks again PS 2 Note to self, whatch the full video before comment.

[@electronicsoldandnew]

Luckily I’m safe on an island so I won’t get caught up in the violence 😊

[@vcdios]

why not? some parts you can hardly find. In ebay 99% are eletro waste.

[@danielsaturnino5715]

@@vcdios , I was kidding of course. I dont care about that. Some people however shrug at the thought.

[@edwardhannigan6324]

Wow, that's a great idea..! So neat and simple. Thanks for sharing, and the fab explanation and tips.. so cool..Ed..UK..😀

[@electronicsoldandnew]

my pleasure

[@mickblackmore290]

I have a question about your Z-diode tester. Why change the current if it doesn't change the readings? I'm building this and need to know. Love your channel. Thanks Mick

[@electronicsoldandnew]

the readings can actually change a bit with. current, but more importantly, it can give you an indication of a failing zener: if the readings are too different at different currents, the diode may be close to its end.

[@paulp2089]

Great idea Manuel 😀

[@electronicsoldandnew]

thanks

[@MattAppleby]

This is genius - so neat. Working on a Braun SK2 atm and following your videos. Assume these would be a good fit for that? Many thanks for sharing 👍👍👍

[@electronicsoldandnew]

They would, but be careful, I believe the SK2 has only a single diode and not a bridge rectifier.

[@MattAppleby]

@@electronicsoldandnew thanks for replying - yes, have restuffed the diode following your video :) Will order the PCB kit to sort out the caps - many thanks for great advice.

[@electronicsoldandnew]

👍

[@neccron9956]

Look up Adapt-a-cap. They have been making very good can cap replacement PBC's

[@electronicsoldandnew]

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[@Wizardofgosz]

Yes. I saw XRayTonyB using those a few months ago. And I think adapt-a-cap is also trying to raise money to restart a tube manufacturing facility. So they get my money 10 out of 10 times. Also, if you don't want to restuff cans, you can get Hayseed Hamfest to do it for you, or you can buy modern cans from CE Manufacturing.

[@electronicsoldandnew]

👍

[@mohinderkaur6671]

you need rfi suppression caps across rectifier - 2 caps will be ok . 2200pf 600v should be ok. some type of fusible link or place to put it maybe a good idea if possible. for filter caps, 2 fat caps end to end would work too. .Fat caps are much easier to find.

[@electronicsoldandnew]

👍

[@mohinderkaur6671]

@@electronicsoldandnew The 3 dropper resistors - change to 1 fusible resistor on the input stage. sometimes the diodes will shortcircuit. this will protect the transformer. Fusible resistors of around 50 ohms 1/2 watt should be good.

[@mohinderkaur6671]

@@electronicsoldandnew Mouser part number 594-AC01004709JACCS 47 ohm 1 watt Fusible resistor . Also try a regular 1/2 watt carbon resistor.

[@alegal75]

Hello, thank you for sharing your knowledge, I have a Loewe Opta Viñeta Luxus radio, I have replaced the selenium rectifier with a silicone diode rectifier, when measuring the rectifier it receives 252 volts in AC and at the DC output I have 313 volts, I need lower the voltage to 275, what would be the combination of resistors to achieve that voltage drop?

[@electronicsoldandnew]

As I said in the video, start with 100 ohms and experiment.

[@alegal75]

@@electronicsoldandnewThanks for your answer, I have done the calculations and I have already found the necessary value, which is 330 ohm, only that the resistors that I am going to use are those large ceramic ones of 3 of 1k/10watts in parallel in order to better manage the heat

[@electronicsoldandnew]

👍

[@flemmingchristiansen2462]

15:10 - Hot glue in a tube radio? Sounds a bit daring. It probably works fine but don't tube radios tend to get pretty hot?

[@electronicsoldandnew]

The tubes themselves do, but they’re always in the top side.

[@robdebije4427]

I tried to order these pcb's from pcbway, but they are charging $43.03 now for 5 pcb's. I then tried jlcpcb and they would have charges $2.00 to do the same. Unfortunately, they recepten the gerbers because dringend production the small pcb's could fall off. They require the tabs to be at least 4mm. Unfortunately I cannot change the gerbers. I would have ordered from pcbway if they had a fair price for these, but $43 is rediculous. I hope that maybe you can modify the gerbers, or ask pcbway why these are so expensive now.

[@robdebije4427]

They rejected the gerbers because during production.....

[@Amperekaefer]

Hallo Manuel. Von Dir gibts im aktuellsten *ELV-Heft* einen sehr interessanten Bericht über Röhrenradios, in diesem ich Dich kennengelernt habe. Abo dagelassen. LG Roger.

[@electronicsoldandnew]

👍

[@markpennington9429]

Hello Manuel. Is it good practice to populate the rectifier board with 3 identical resistors or can they be of different ohm values?

[@electronicsoldandnew]

They can be different, as long as the combined resistance value in parallel gives you what you want. the only down-side is that the power dissipations don’t divide up equally amongst the resistors, and you could get one heating up too much.

[@markpennington9429]

@@electronicsoldandnew thank you

[@markpennington9429]

And BTW, your boards are fantastic. Well done.

[@electronicsoldandnew]

👍

[@DerekHerbst747]

What a great idea!! Well done amigo!! :)

[@electronicsoldandnew]

👍 😊

[@jefferyboyle7276]

✌ 🎸

[@electronicsoldandnew]

👍 🎸

[@waynegram8907]

What are the advantages of using Selenium rectifiers and Selenium Diodes compared to using Silicon rectifiers and Silicon Diodes?

[@electronicsoldandnew]

There is no advantage. These selenium rectifiers were used before silicon diodes came into existence.

[@waynegram8907]

@@electronicsoldandnew But selenium rectifiers and selenium diodes have a higher input to output "voltage drop" across the selenium component? any reasons why?

[@brcd1314]

How about putting resistors on AC side - lower voltage drop, less heat to dissipate. Any reason not to?

[@electronicsoldandnew]

You can, and sometimes you have to if the input selector is only for 220V mains voltage (we now have closer to 240V in Europe). This helps to reduce the overall voltage so that your heater supply also comes down to about 6.3VAC. However, when you replace the selenium rectifier with silicon diodes, the rectified voltage will always be higher than you need because the selenium rectifier has quite a high voltage drop, which the silicon alternative does not. It is this drop that you’re trying to achieve with these resistors.

[@brcd1314]

@@electronicsoldandnew Maybe I didn't explain my comment/question. I am suggesting that resistors be first on the rectifier replacement circuit board, then the diodes. In other words, on the circuit board with resistors and diodes - AC in, then resistors, then diodes. This makes voltage adjustment needed (to compensate for the difference between silicon and selenium) roughly 1.4 times less.

[@electronicsoldandnew]

You may have a point there. Quite honestly, I’ve never given it any thought, and as far as I recall, nor has anyone else. I may be wrong, but I think you’ve just added a new idea to this topic, which isn’t just taking further what someone else has thought up. Thank you. Anyone see a problem with brcd131’s logic? Please comment.

[@brcd1314]

@@electronicsoldandnew I wish I could take credit for this idea but I can't. I remember hearing someone say it in passing in a radio repair video so I gave it a try, and it worked (reduced voltage drop/resistor wattage) for the few times that I tried it.

[@electronicsoldandnew]

Well, thanks for mentioning it here. I’ve done literally dozens of these and never gave any thought to an alternative layout.

[@cbiz8]

Hola Manuel! How can i order this PCBs? Tienes algún código de producto? Gracias!

[@electronicsoldandnew]

You can get the Gerber files from here: www.pcbway.com/project/shareproject/W224132ASE24_Gerber_filter_caps_rectifier.html

[@cbiz8]

@@electronicsoldandnew Ok; pensé que PCB tenía stock o los fabricaba en el momento informando algún código de producto. Muchas gracias.

[@electronicsoldandnew]

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[@CT1JQJ]

Thanks for sharing!

[@electronicsoldandnew]

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[@kennethiman2691]

Instead of hot glue use shrink tubing.

[@electronicsoldandnew]

Even better. Good idea. Thanks.

[@jdmccorful]

Really like the diode replacement board. Thanks for the look.

[@electronicsoldandnew]

pleasure