As an electronics engineer that finally returned to this field for fun, I like to restore old tube radios and tinker with just about anything in the field of electronics that takes my fancy. It generally includes some audio application, but that is not a rule. Tube radios, guitar amps and effects pedals, audio amps and speakers, and even Ardiuno projects have served to keep me at my workbench until all hours and out of trouble.
This channel serves as a personal video log of some of the projects that come to life (or not), and to share it with any other aficionados out there who suffer from the same ailment. Email: mcaldeira (at) icloud.com
Very respectful greetings from Merida Venezuela in my career as an ING in electronics, I also dedicated myself to the repair of equipment and one of those coincidences on my workbench I received a Radio Braun T-1000 with an audio failure which required the diagram, and due to life's circumstances I took on the task of looking for information about the equipment and thanks to God and to you I will be able to put this unit into service since it is a very valuable piece of equipment. and it is original, thank you in advance and good luck for transmitting such valuable information, may God always bless you, my name Hender Avendaño, good luck in your work. ✨💫🇻🇪
Lightburn is great and worth the price. I run it on two Pc's, the main PC and the one connected to my laser (modified K40 with my own driver running gerbil). great fun getting the data right for a home made driver board, but you learn a lot. Watch out somethings like leather can produce some not very nice flumes.
Manuel, I've said it before but I'll say it again: Thank you for showing us what is possible. We can fabricate parts and accessories for this restorative work. Bring it on!
Ideally you need this in a laser-specific enclosure, vented to the outside of your workshop, but I reckon that it’s a fabulous addition to your workshop.
Agreed. However, space is an issue as I use my home office as a hobby workshop. This tool gets stored upright and just about leaves my “workshop” useable 😊
I’m just refurbishing a Grundig Mandello GB and decided to try this to get B+ at the correct voltage. The PCBs have arrived this morning so as soon as the MOSFET arrives I’ll get the job finished. Thanks for this 😊
Very nice. I posted a link to your video to the Audiokarma Fisher forum. Just wondering if there is a role for this laser in restoring a messed-up Fisher faceplate.
I build this about the same way. but i have a problem with the neonlights in the switches, when i switch one of them on, all the neon lights go on, they get there power of the common of the bulbs via the bulb that is not powered on
Welcome to the wonderful world of laser cutting Manuel. I have made backs for two radios so far, I haven't put the videos up yet but they came out fantastic. I was impressed you worked out the software so quickly, I have been using it for 18 months and still struggle 😅 For the text engraving, try turning off the air assist, you will get an sharper edge. The honeycomb cutting frames are a great addition. Lightburn will draw a square or rectangle around the project showing where the material needs to be positioned, you shouldn't need the orange outline. You can also set Lightburn to fire the laser with minimum power so you can see where it will cut during the 'Frame' process. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jLrWm-Q85Gs.html&ab_channel=HobbyLaserMachine
Thanks for the tips, Dave. The software can be a rabbit hole, but I’m getting there. It’s not as easy for me to learn new software like I used to 😊 Takes a few more attempts.
Brilliant device. I think you can set the IP Address to use DHCP (automatic via your wireless accesspoint) and connect using the laser cutter's hostname from that point.
Hello Maestro, I've been looking for such a tool for ages... Say, can it engrave also aluminium panels, so the front panels of my audio equipment? Thank you!
I tried that and it seems to work on aluminium especially if it’s anodised. I haven’t got the power and speed settings sorted out yet for metal, so haven’t done much with metal, but it seems to work. Not sure yet Olof the colour will be good enough
The good thing about monitor screens and youtube is that the damaging part of the spectrum doesn't come through. LED and LCD screens are just not capable of reproducing the damaging range of the spectrum. Damage to the camera, that I can't comment on. It is possible, depending on physical filtering, that long term it could damage the camera, but short term I don't think you'll have any issues. I've seen a few reviews of different laser cutter/engravers and some of the creators have built a compartment to keep them in and allow exhaust of the smoke too. Have to admit this one is one the higher quality ones I have seen reviews for. I can see you getting a lot of use out of this.
@@electronicsoldandnew Absolutely. The things you didn't know you needed until you got it. :) All those panels that you may have used stickers on before could be laser engraved. All sorts of things
Fascinating. With this and 3D printing, it opens up a lot of new possiblities. Radios that would have been put in the bin or on the doner-only shelf could now fall into the 'restoration potential' category!
That looks like a nice bit of kit. Is the laser strong enough to burn the copper from PCB's to make your own PCB's? Or could you use it to burn ink of PCB's ready for etching 🤔
Awesome stuff, I’d look into logging into your router to see if you can set the laser on a static IP address so that it does not change when devices connect and disconnect and then you won’t have to change it
Wow the Laser cutting took, 3-D printer, best take the ladies out for an extravaganza as reparations payment. When you feel comfortable with new toys, how about a solid-state home brew project utilizing a PCB maybe a custom Bluetooth speaker with direct input jacks for your guitar.
Great work and great video. Only thing I have to say is that I whould never have a laser connected to the internet with the risk of hackers and burning down my house. Safety is the number one thing to think about. Thanks.
I ordered 5 bluetooth boards from PCBWAY on Monday and they arrived on Friday of the same week( I live in Iowa, USA). The quality of the boards is impressive. I'm bummed that I didn't order 10.
8:53 Bon dia! Thank you much for your videos that are extremely instructive! I’m currently restoring the same. One question : isn’t the values of the coupling capacitors (3.3nf) very low and damping significantly the bass ? Have you tried something like 0.5 uf we would see more in tube amps ?
I think the reverb is only meant to be used with a monophonic sound input. I had a surround sound processor ( my first) which used to make old 1930’s 78rpm Opera recordings sound very lifelike.
You said that you couldn't add the circuit to your Braun radio. Would this be an improvement, or is it not possible to replace a half-wave rectifier with a full-wave one?
I could replace it but I don’t want to change the circuit too much from its original condition. In restorations, I try to keep it as original as possible.
EXCELLENT !!! I’ve decided to have a go at building this tester , going to have onboard sockets for the audio amp/ and preamp tubes I generally use and a socket outlet for any oddball valves I encounter , I’ve ordered the pcbs …. And led meters, can’t get the peak meters in the uk for a relatively cheap price as far as i know can’t wait to get started !!!
@@electronicsoldandnew Thanks , i have an update , got the pcbs , (great quality ) ordered a custom toroidal transformer 250v@2A and 8v@5A , even found a pcb on pcbway that gives me octal, Noval7 and Noval 9 on a single pcb with paralleled pins so I don’t have to do the tricky wiring of the sockets !! I have three sets of these pcbs going spare ( psu pcb, opto/relay board , and the tube base board) which I’m willing to pass on for a minimal fee ( to fund the build )plus postage if anyone requires these please drop me a msg ill keep you guys posted on the build
Clever design. I was watching for the voltage to change as the FET warmed up, but it didn't. I thought, doesn't the Vgs/Drain Current characteristic change with temperature? I looked at the datasheet for NTP067N65S3H which I recently used, and for a given current, Vgs changes by as much as half a volt between 25C and 150C. This would be magnified by the potential divider ratio of the trimpot. I guess it's more than accurate enough for a valve radio supply, and a very economical design. Edit: by the way, I used Pcbway on your recommendation and can recommend them. Quick delivery and perfect product quality.
I understand the need for a voltage drop, but see two issues with a resistor only circuit: startup current vs voltage drop and dependence on the turn-on curve of the mosfet. Suggest adding a TL431 (cheap $0.30) as an active zener in your circuit. Lookup 'Variable power zener circuit using tl431.". It will achieve a constant voltage drop independent of startup current, temperature and mosfet characteristics.
Some of the loveliest tea available in Europe is grown in the Azores. For over 200 years, cultivation has been undertaken. Gorreana Tea Company produces over 40 tonnes of Organic green and black teas per year on San Miguel, continuously since 1883. 🇵🇹
👍 I know ….. still can’t seem to take to it 😊 In fact. We (the Portuguese) were the ones who introduced it to English society, through Catherine of Bragança, so she was probably looking for another market to export to, rather than convert her own countrymen to enjoy it themselves 😊
@@electronicsoldandnew I myself take coffee. I drink a spearmint tea that my parents brought back from Portugal in the late 60s that grew in a small river near Beja, and that grows nicely here in Saskatchewan Canada. I did not that part about Queen Catherine..thanks for that!
You should read the book, “Portugal, the first global village”. It was written by a retired Times Reporter who moved to Portugal in the 70s, and lists numerous facts about our ancestors that most of us have no idea about. By the way, I believe an old Varsity (University of Natal, Durban - Electronics Engineering) friend of mine, Luis Rocha, lives (or lived) where you are. Now that would be a coincidence if it was someone you know or knew 😊
Great idea and well explained and executed as always! One thing I'd love to see in a follow-up is a failure mode analysis. What happens if the MOSFET fails short, if the pot is shorted etc. Are there any circumstances where this circuit could add a new risk or is not suitable? A systematic discussion of any potential issues would be a great addition.
The failure modes are quite straightforward: shorted or open. If it opens, the circuit is simply cut off as if you’d used a switch to switch the supply off. If it shorts, the original B+ will result with no drop. The circuit should be able to. Andre the extra 10 or 20V with no major issues.
Why not put two thyristors into the rectifier bridge instead of diodes and fire them in a way so that Ub will be at the voltage you like ? Of course it will introduce some switching noise, but maybe it is not as bad as one could fear because you switch the thyristors on at a low voltage already and if you shield and filter it properly with a few ferrites here and there, the radio may not be influenced terribly. HP used this in it's high wattage lab power supplies before high frequency switchers came into use, if I remember right.
@@electronicsoldandnew sorry to trouble you,the fet you say to use is £14 here in the uk,i have a 2sk4005 from an old laser printer,would that work in this?,cheers Paul.73
Wow ! This is just brilliant Manuel and would you believe i was just looking at solutions for replacing the AEG rectifier on the Grundig 2220CA i'm working on at the moment ? Of course i will still have to build a new case in order to adapt it to the chassis and fit this board, but at least adjusting the DC output will be much simpler. I have used your other rectifier board on a Blaupunkt Riviera 2540 USA i just finished restoring and it has been working flawlessly, although i find the diodes while not going out of max specs do heat up quite a bit. I wonder if this is normal ? Anyway for those interested in seeing my rectifier replacement and if you allow it Manuel, you can watch it in the final episode of the series (part4) starting at 18:45m. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-E4X34IVKCyE.html
@@electronicsoldandnew Ok great, thank you Manuel. I sort of thought the diodes' heat level wasn't too too bad, but i just wanted to make sure with you. Thank you for allowing my footage, trying really hard to start my own channel, but man i'm really more a photographer than a cinematographer. I don't know how you guys do it on a daily basis :-)
I like the design of this as it simplifies the adjustment of the B+ difference and it can be setup with a lower input voltage. This does of course bias the whole chassis above earth and in some cases this can interfere with the bias setups already exisiting, so this would be unusable. Also you would have to be careful not to add a mains earth or ground earth to the chassis. I can see the point about about the risk of high potential contact if placed in the B+ line, but if needed could this be potted (allowing access to trim pot) or non metallic bolts used to reduce contact risk? I know if extra heatsink is required, this would rule out the chassis.
If the radio doesn’t have any bias arrangements around the ground system, and if the chassis is connected as a general ground, earthing the chassis shouldn’t be an issue. This can just as easily be used on the hot side, with some extra precautions, as you mention.
I see one problem with this circuit. If you turn the potentiometer all the way down, the mosfet never turns on, and the full voltage will be over the potensiometer. The potentiometer will then dissipate about 2 watts. You should add a fixed resistor at the bottom of the potentiometer to reduce the maximum voltage allowed over the mosfet.
@@electronicsoldandnew While you're at it, I suggest you out put a high value resistor, like 1M, between the top of the potentiometer to the whipper. The will prevent disasters if the potentiometer gets oxidized and the whipper loses contact with the track. 🙂
Interesting. I may be missing something but I don't think this would work on the Saba Freudenstat I did recently as that is one of those radios where the negative output from the bridge rectifier is connected to chassis ground via a couple of resistors to provide a grid bias potential. BTW if the MOSFET tab can be electrically connected to chassis it "could" be mounted underneath with a spacer between it and the board and thus be bolted direct to the chassis if cooling ever did become an issue? Personally I think I'll continue to use a large bridge rectifier (usually a Comchip GBPC3510-G which doubles as a tagstrip!) and a power resistor which can both be safely bolted to the chassis. That also allows for an extra 50uF capacitor placed immediately after the rectifier to add an extra (probably unneeded 🤣) stage of pi filtering, if that's a phrase? But variety is the spice of life and thanks as always for sharing Manuel. ⭐
That Saba needs the bias, so it probably won’t work as it’s presented here. Also, those SABAs draw a LOT of current, which will really demand a good heatsink solution.
