![David Mills](/img/default-banner.jpg)
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David Mills
United Kingdom
Приєднався 4 тра 2007
Technology and Timelapse.
Some short videos of projects, things I find interesting and the occasional timelapse.
Some short videos of projects, things I find interesting and the occasional timelapse.
EverReady SkyLeader part 3. Final.
just a very quick video finishing up the resurrection and repair that the 1958 EverReady sky leader radio. Longwave now works and I've got the external antenna socket working.
Переглядів: 363
Відео
EverReady SkyLeader Resurrection part-2
Переглядів 5972 місяці тому
Part two of the rather long project to resurrect a 1958 vintage EverReady radio. Several false starts in the video, but we get there in the end.
EverReady SkyLeader Resurrection part-1
Переглядів 2,8 тис.4 місяці тому
Trying to fix a 1958 vintage EverReady SkyLeader medium-wave and long-wave AM set. First part is just workig out what's missing and what's wrong. In the seond part I'll fix some of the issue I identify in this part.
Dansette 222 resurrection and repair.
Переглядів 5 тис.5 місяців тому
Diagnosis and repair of a 1961 Dansette 222 Transistor radio.
Polar Alignment issues
Переглядів 209 місяців тому
Trying to work out why the polar alignment on my telescope wanders when I move the telescope.
A quick experiment with permeability tuning
Переглядів 912 роки тому
Just playing around on the bench with a coil of wire and some metals to see which gives a good change in inductance when put inside an air coil.
Quick look at a electric motor demo
Переглядів 372 роки тому
School electric motor demo I got from a school teacher's estate clearance. It needed some work to clean it up before it would work. The commutator needed cleaning and the brushes bending back to make contact. It probably needs some oil to make it run a bit more smoothly. POwer requirements are 4v DC at around 3A
Testing an germanium transistor radio design
Переглядів 2422 роки тому
This is circuit 8 from Clive Sinclair's 148 Practical Transistor RX book. I lack high impedance headphones, and an impedance transformer did not give decent results, so I capacitively couple of outpout from this radio into an external audio amp. It's not a very good radio really.
Two mushrooms growing overnight
Переглядів 2113 роки тому
A quick timelapse thrown together to see how these two mushrooms would grow. Time span is from 9pm to 7am the following day. One frame every 120 seconds.
[8] Concentration, Moles, PPM & PPB
Переглядів 2434 роки тому
The eighth in a series of videos covering some basic concepts in science, aimed at those working in the heritage sector. This video finishes up our extended look at concentrations and solutions. It introduces the concept of the Mole and how is may be used. It would be helpful to have watched video 4 before this one.
Local fabric density in L2 vertebral body bone by high contrast resolution x-ray microtomography
Переглядів 164 роки тому
A virtual poster for the Bone Research Society conference of 2020. There's a follow on twitter thread for this work here : DTL/status/1280445238667083778
Interesting effect while building an oscillator.
Переглядів 1554 роки тому
Testing a Vackar-type oscillator I'm building for a radio I plan to construct. I grabbed a handy radio to listen to the oscillator note to get some idea of the quality of it. When I tune the radio to roughly twice the frequency of the oscillator and bring the radio antenna close to the oscillator I start hearing radio stations that are not on the frequency the radio is tuned to. I didn't listen...
[7] Dilutions
Переглядів 2744 роки тому
The seventh in a series of videos covering some basic concepts in science, aimed at those working in the heritage sector. This video, based on a viewer request looks at producing solutions with useful concentrations from stock or incorrectly made concentrated solutions. It assumes you have seen video 4 in this series.
Dansette 222 Repair
Переглядів 1,1 тис.4 роки тому
A rambling repair of an old Dansette 222 radio picked from the junk pile in the shed. The radio was working last time I used it, but that was about 15 years and two sheds ago. Can we make it work?
[6] Chemistry - Aromatics, Alcohols, Ketones and Carboxylic Acids
Переглядів 2124 роки тому
The sixth in a series of videos covering some basic concepts in science, aimed at those working in the heritage sector. This video follows on directly from video 5, we extend the ideas learned in video 5 and look at similar, but more complex and interesting molecules. We meet carbon atoms in rings - aromatic molecules, and also alcohols, acids and ketones.
[5] Chemistry - Drawing And Naming Molecules Containing Carbon.
Переглядів 3254 роки тому
[5] Chemistry - Drawing And Naming Molecules Containing Carbon.
[4] Lockdown Conservation Science : Percent Solutions
Переглядів 9034 роки тому
[4] Lockdown Conservation Science : Percent Solutions
[3] Lockdown Conservation Science : Bonds between atoms and molecules
Переглядів 5214 роки тому
[3] Lockdown Conservation Science : Bonds between atoms and molecules
[2] Lockdown Conservation Science : Atoms
Переглядів 6064 роки тому
[2] Lockdown Conservation Science : Atoms
[1] Lockdown Conservation Science : Introduction
Переглядів 1,2 тис.4 роки тому
[1] Lockdown Conservation Science : Introduction
Fault Finding & Repair Of A Transistor Radio
Переглядів 17 тис.4 роки тому
Fault Finding & Repair Of A Transistor Radio
Interesting feature of a cheap padlock.
Переглядів 525 років тому
Interesting feature of a cheap padlock.
Very interesting indeed.
excelente video, es una escuela poderosa para transmitir la enseñanza en electronica
Radio is too loud help
Working
😮 voo
I lov ❤ this oscillator. ..mor video. How to make . ..this
Thanks for sharing ❤
الي عندي ولا شي ترب فقط شو ماعليك منهم في غرفتي كله جذب اغرضي كلهم مب مالي
في بيت راعي السيفك الابيض
يقولك في بيت قم كل في بيتنا
Thanks bro
This was my first radio as youth. Purchased from Currys at 11.5 GUINEA on credit over 12 months. 13 pounds in all. I think mine was a later model and looked much nicer. It was dark green with a silver metaled area over the speaker. Inside looked much the same but the OC81 output transistors did not have a heatsink clip fitted. 600mW output if I recall. A very nice radio. Just found your channel. Just a very small observation, if you don't mind. Your audio is very sibilant at times.
I've seen a few online that are in different colours - when did you buy yours?
@@DavidMills_Physicist Hi David. Mine was in fact a Dansette GEM purchased around 1963/4. Quite a few photos online. I have no idea what ever happened to it.
that 100uf measuring 165ish is perfectly ok in terms of capacitance, many older ones had a positive tolerance of 80%! as for the 8 ohm esr, it may well be ok in this circuit, dont forget these arent special low esr types, it wasnt a 'thing' back then , low esr was rarely required
Yeah, the capacitors don't seem overy critical - in my first repair video of this radio model most of the caps are cracked or otherwise duff - it still worked. It's just that I'm doing this as a repair for someone els, and I won't want it to die in service, so a cap change made sense.
@@DavidMills_Physicist cracked hunts, at low voltage, wont be a problem, and i've found smaller/lower value ones such as 0.0047 or smaller more a problem, than larger ones , in this sort of device blob a bit of superglue or wood varnish in the crack and it'll be ok,
@@andygozzo72 The first one of these I repaired the cracked caps were entirely open circuit - radio still worked after a fashion.
@@DavidMills_Physicist larger value cracked hunts , such as over 0.02 uf , i find are usually acceptable, below may be bad, i've come across caps of similar construction, except light brown colour, that had gone very leaky even at low voltage, they werent marked with any brand, though ..,
New subscriber from Canada. Interesting radio. I've never seen one of these before.
A few days after I posted this video a neighbour asked me if I wanted an old radio and handed me another one of these. I've not tested it yet.
@@DavidMills_Physicist Must be nice to have neighbours handing you vintage radios. That vernier reduction drive is a nice feature on this radio for precisely tuning in stations.
@@electronixTech They know I like old radios, I think this other oen came from a relative's attic or someting. Cause it cracked, but insode looks clean - it's not been stored in the damp.
I remember having a Dansette 222 given to my by an aunty in about 1976. It's mainly OC45 and OC81 transistors.
To be exact Michael, OC44/45. 2 x OC81 1 x OC81D if I recall. Was a very long time ago.
I finished mine - replaced all the Hunts and electrolytic caps and it seems to work well. Not overly sensitive but reasonable sound quality!
Congratulations on the repair, I found tweaking the IF for max signal on a weak station did improve sensitvity. If you have a sig gen you can do a proper alignment, but it's so wide, you really don't need anything fancy.
I thought about that but didn't in the end (I've never done an IF alignment before although I know the theory!). I was just repairing/cleaning it up for a friend for sentimental reasons - it was her father's radio back in the 1960s. I have to say that it was much easier to work on than the valve sets I've done before. I put the new caps in the same locations as the originals, so it doesn't look so "empty" inside.@@DavidMills_Physicist
@@gordonlyon2351 I've just been given another one to fix. The capacitors look a bit better in this one, but the case is trash. Might end up making one good one from the two.
@@DavidMills_Physicist I was lucky in that the case on mine was in good nick. It only needed a clean. There's a small crack on the bottom but I just put a bit of superglue on it and it's fine. I had to be a bit experimental with the values of some of the caps but it seems to have worked out OK.
@@gordonlyon2351 i have a 222, rough case but working nicely, virgin unrecapped as they didnt need changing, hunts caps used in low voltage/low impedance circuits like a transistor radio do not need replacing on sight, even if cracked, only if theyre actually bad, such as gone open (any dc leakage on low dc, which will be minimal or non existent, is irrelevant in low impedance circuits)
Nothing to understand...
I enjoyed the video thank for putting it on UA-cam regards Allan g6tmo
thanks! I'm part way going through the same process on a friend's 222. My case is in better condition and the "dial" has survived my cleaning. I'm waiting on the new capacitors to arrive. I had the devil's job getting the knobs off of the volume control and wave change switch without breaking them!
I was lucky, I didn't have to remove those. The trick for a stuck tuning dial is two fold some think cotton material around and under the dial then pull up, it spreads the load and prevents the dial cracking.
شكرا جزيلا لحضرتك على هذا الفيديو
Awesome... My kind of troubleshooting..
Dave would you have an idea to point me in the right direction volume on Jukebox Classic just turns itself to highest volume can happen when you first turn on or after been on for a few hrs..could you help me..please ..by pointing me in the right direction..thankyou Trevor
Proper physics is magic!
FYI I start by spraying some cleaner into the band switch and vol control. Electrolytic capacitor kits are cheap buy them on eBay I usually just replace them. Loose and bad solder connections. Deoxit is good for cleaning.
I wanted to like this video but I can't bring myself to take it off 69 likes. Sorry mate. Slightly terrifying video in a weird way, love that spicy air.
Same
Hmm yes, the spicy noise
This is cool
It's not repaired. After you swapped the caps and retouched the solder joints there is still little volume. The amp is good because you could hear a decent output from the signal generator. Forget the signal generator you need a signal tracer. You havent found the problem.
Your voice volume is to low to hear well.
This is gonna be my plan
The immortal snail wandering around my office in a hamster ball
Hi David, I don't mean to go off topics from your video but I'm looking for some help. I plan to be getting a Spectral Instruments 800 series CCD and was wondering if you still had the LabVIEW software? Cheers-Josh
Hi Josh, I'll check. I'm pretty sure I still have the original CD for my 800 series camera around.
@@DavidMills_Physicist Thanks man! Excuse my ignorance, but I’m assuming you’ll be able to just send the Program over without the CD once you’ve got in on your computer? I was just introduced to LabVIEW recently and my knowledge of it is very limited. I’m planning to use this CCD experience to learn a thing or two about talking to devices.
@@Sardinie14 I've put a copy of the software that runs with the 800 series camera here: www.dropbox.com/sh/5ro3idsvefvpgkk/AAB6Ue3tFy7FELTJw5JAiXD3a?dl=0 Let me know when you've got it and I can remove the link. The Labview is compiled (I think, I don;t really know labview) so I'm not sure if this will be much use to you. Good luck with your project.
@@DavidMills_Physicist I've got it. I'm not sure if it will be of much use either but it is a start! I'm a physics student currently being introduced to LabVIEW for my research. But, I also love astrophotography. I saw mike's video about these cameras and figured I would give it a go to try and learn a thing or two. If it winds up as an expensive paperweight. So be it haha. Thanks again man, really appreciate it. Cheers - Josh
Hi, good work. Can you please share the schematic? I have the same problem with the 3.3V deliver by the esp32, which isn't enough to turn on the mosfets I'm using as drivers for a DC motor. It'd be really helpful
I'm sorry - I don;t have the circuit diagram to hand, it was a quick experiment. The transistors I used were 2n3904, so you can probably reverse engineer the circuit if you pause the video when the board is shown. Good luck.
Interesting, thanks for sharing
Back in the '80's, I used a 1N4007 to check if my medical X-ray system was actually working. I used an O'scope, though.
David, this is great. So so helpful to get a refresher on sciences which I have not studied since my conservation studies. Fantastic series!
Well done David, nice little fix. Contrary to earlier comments you can fix radios without a signal generator - I've done it. So many radios are given up as dead when many faults are dead simple. Battery terminals, dirty volume Pots / switches, broken wires, bad joints etc, etc.
Thanks - I've been enjoying fixing a few old radios during the various lockdowns. I've got another on the bench now, I should make a video for that one - it's missing just about everything.
This has taught me about these functional groups much more effectively than years of trying to memorize lists and tables of them instead! Seems the combination didactic and discursive approach is just perfect. Thanks so much.
Wonderfully delivered. Thanks so much!
Thank you. I am planning to make more videos in this series, I just need to find some time...
Thanks for posting these videos. I'll be watching one per day. I am in my first year at a new course for books and paper, so this is truly a perfect accompaniment to all of my other online learning...
I like playing with negative resistance oscillators.
Thank you for doing this series, its very good for repeating the almost long lost kemistry from uni. I hope that you will continue with more kemistry and conservation specific topics in the future!
No one has the knowledge to repair a transistor radio without a signal generator ???
I can, and have done many times, but now I have the tools why makes things harder than they have to be?
@@DavidMills_Physicist Then people can not learn how to do it unless they spend $$$. It just turns off the youngsters who want to learn and can not spend $$$.
Excellent bit of information here! Thanks for such a wonderful presentation.
Nice job👍👍
Thanks. This is really helpful, I'm still in high school and the way you explain it is really easy, for me, to understand. 😆
Thank you! Good luck with your studies.
Sir, what's the correct procedure to check voltage in the radio (germanium tr) circuit.
It's a bit difficult to go into in a comment, but basically you're looking to see if the base is biased (has a voltage around half the supply voltage on it) and that there is voltage on the collector. Remember, most if not all germanium transistors you'll come across are PNP, so the emitter will be positive and the base & collector will be negative.
awesome work,, but i dont have signal generator to find this fault
Thank you David, a refresh would be great
Really good refresher of the chemistry lessons during my conservation studies. Looking forward to the next videos!
And you nice comment, I'm just dealing with some other issues moment and plan to get the next couple of videos out in a few days time