Thanks! I used 1K resistors. I took inspiration from this video (you can see the schematic around the 5 min mark): th-cam.com/video/rBITfrbDbbI/w-d-xo.html&ab_channel=AntiqueRadioArcheology-WilliamMorris
Thank you for the great restoration story! Can you tell me - what is value of the drop voltage resistor? I use different from 68 to 100 ohms. It depends on a radio. When I am too lazy I just put a selenium bridge rectifier. If it is necessary to have the chassis authentic I have to open an old selenium rectifier and put 4 single (each shunted with 22nF capacitors) diodes inside.
Hi Patrick, in this case it was 330 ohms. Usually I start at around 100 ohms and play with the values until the desired output voltage. I like this article by Rich Bonkowski: w5rkl.com/wp-content/uploads/2022/07/RBSelenium2.pdf
these small hi-link PSU bricks are just the same cheapo chinese low-power bare PSU PCBs you can buy in various places, except they took those modules, soldered long pins to them and potted the whole thing in a plastic shell to sell as "industrial" PSU modules and other nonsense. They suffer from the same low component quality (electrolytics mainly) and short lifespan as the bare PCBs, with the main difference being that you can't fix the potted ones when they fail (or prevent them from failing in the first place by replacing the caps before putting them into service). You can find examples of the bare PCB/non-potted ones via google image search with the term "5V 700mA power supply". Seems like the potted ones are slightly de-rated for whatever reason (heat?)
That makes sense. Still, it seemed to me the easiest way to get a PSU with ground isolated from the radio. It's probably okay if the BT module works for a decade or two, since by then we're likely to be using some other protocol for audio devices. There's some interesting videos from Electronics Old and New about how to supply the BT module by adding a new winding to the radio's power trafo (th-cam.com/video/eWfsWNUpSNs/w-d-xo.htmlsi=1NVTFHwa5PjrME6d) or from the magic eye circuit (th-cam.com/video/TeoWENXwcWs/w-d-xo.htmlsi=gl6BpXF-ak7jAiHA), but I thought they would be overkill for my case. How would you do it?
Nice, inspirational restoration. What value resistors you used in your blutoothe module for conversion from L/R to mono channel. Thanks.
Thanks! I used 1K resistors. I took inspiration from this video (you can see the schematic around the 5 min mark): th-cam.com/video/rBITfrbDbbI/w-d-xo.html&ab_channel=AntiqueRadioArcheology-WilliamMorris
Thank you for the great restoration story! Can you tell me - what is value of the drop voltage resistor? I use different from 68 to 100 ohms. It depends on a radio. When I am too lazy I just put a selenium bridge rectifier. If it is necessary to have the chassis authentic I have to open an old selenium rectifier and put 4 single (each shunted with 22nF capacitors) diodes inside.
Hi Patrick, in this case it was 330 ohms. Usually I start at around 100 ohms and play with the values until the desired output voltage. I like this article by Rich Bonkowski: w5rkl.com/wp-content/uploads/2022/07/RBSelenium2.pdf
@@TacianoPerez , thank you for the information!. Saved it in my tech library.
great video.Where do you find the service manuals for the radios?
Thanks! I find most at the website of the Dutch Association for the History of Radio (NVHR): nvhr.nl/docs/schema/schematheek.php
these small hi-link PSU bricks are just the same cheapo chinese low-power bare PSU PCBs you can buy in various places, except they took those modules, soldered long pins to them and potted the whole thing in a plastic shell to sell as "industrial" PSU modules and other nonsense. They suffer from the same low component quality (electrolytics mainly) and short lifespan as the bare PCBs, with the main difference being that you can't fix the potted ones when they fail (or prevent them from failing in the first place by replacing the caps before putting them into service). You can find examples of the bare PCB/non-potted ones via google image search with the term "5V 700mA power supply". Seems like the potted ones are slightly de-rated for whatever reason (heat?)
That makes sense. Still, it seemed to me the easiest way to get a PSU with ground isolated from the radio. It's probably okay if the BT module works for a decade or two, since by then we're likely to be using some other protocol for audio devices. There's some interesting videos from Electronics Old and New about how to supply the BT module by adding a new winding to the radio's power trafo (th-cam.com/video/eWfsWNUpSNs/w-d-xo.htmlsi=1NVTFHwa5PjrME6d) or from the magic eye circuit (th-cam.com/video/TeoWENXwcWs/w-d-xo.htmlsi=gl6BpXF-ak7jAiHA), but I thought they would be overkill for my case. How would you do it?