Repairing burnt out transformer. Oscilloscope repair.
Vložit
- čas přidán 18. 10. 2012
- The Arduino code reading the photo interrupter and stepping the motor is here:
nicknorton.net/?q=node/1
Maplin Electronics no longer sell transformer kits.
At the time of posting this video, transformer kits are available from:
livinginthepast-audioweb.co.uk - Věda a technologie
Fantastic bit of work on that semi-automatic winding jig; thumb up!
Yes many of my radios have 25 cycle or 25/60 cycle transformers...I heard they run cooler because of there size.I love big heavy vacuum tube amplifiers and radios and they sound soooo good and so smooth
Excellent work bringing life back into the scope, "well worth the effort" congratulation's on a job well done.
To be sure about the number of turns required. Feed 10 turns of wire around the core and measure the voltage with an accurate meter. Divide by 10 to get your exact voltage per turn. Use the thickest wire you can, while still leaving enough area for the required amount of turns to achieve your voltage.
There is a link in the full video description for someone still selling kits.
Proper respect for a loved piece of kit - Kudos dude.
Just an Arduino reading the photo interrupter and in turn pulsing a stepper motor. My arduino code is up in the video description.
The stepper driver circuit was borrowed straight out of a document scanner
but the useful part was no more than a ULN2803 driver & motor.
You'll have no problem making that, lots of examples on the web.
I used a battery powered drill to turn former.
Lots of speed control options for that.
I used a cheap unregulated AC to DC power supply plugged into a mains variac.
25CPS, a nice collectors piece. An interesting repair indeed.
Nice scope brought back to life again.
The wire diameter is 40SWG (0.125mm)
The HT current draw is very low, about 0.04A
Would like to see a video on the winder setup I would like to build one. Amazing work you rock!
Thanks, luckily I had all the bits 'n pieces handy to cobble the jig together conveniently.
I use PTFE tape between my own windings and find I have no problems. Nice video.
actually I already too it apart several years ago , and it came apart really easy........I took it apart because of curiosity (stupid) and the filament winding did look like it burnt a bit ....It is actually a 25 cycle unit.I still have the bobbin and the wire I am going to get new wire of the right guage and hand wind it very carefully even if I do 100 or so windings a night and it takes a month, or I may get or make a winder.I will make video of the transformer and send to you later on...
Hi! Wow!!! Your skill level is at the highest form. Thank's for showing how it's repaired correctly. The winding counter device is cool to say the least.! Your a true teacher.
The Arduino is plugged into a PC over USB.
Arduino prints its output to the serial port on the PC
(In my case /dev/ttyUSB0)
Using a Nokia N900 with a SSH connection to the PC
over Wi-Fi to view what's being sent to the PC serial port.
Thanks for your comment.
Good point.
The insulating layer just reduces stress from breakdown across the thin enamel coating. In this case, just over 80 Volts AC is induced for 500 turns.
Although 471 Volts AC is not high compared to some multi-segment HT windings.
The 471 VAC winding feeds a tripler circuit for the CRT anode voltage.
The insulation between the 31.3 Volt winding and the 471 Volt winding has
to be good for 2KV.
Almost 500V and isolated what seem to be with ordinary tape. Kapton is the only thing good for this to be really sure and isolate it in a special way so there is a big isolating gap between the wires because of the Kapton.
wew superbly done Nich i really enjoyed that. really nice work very old school its good to see that there are still people willing to have a go at this kind of repair.
Thank you. It's old, but still in mint condition. So I could not possibly discard it.
I powered up the scope for about 30 minutes I guess with the case off. But didn't notice any discernible temperature increase from the main Tx or my retro fitted one. Both transformers operate well within there VA rating.
Great.you made great machine of your own.that winding and unwinding of transforner gave me more knowledge on it
Used to rewind the little microphone pickups in cordless phones. I musta been nuts.
I liked the arduino set up for winding the trafo .
Ingenious setup!
Absolutely brilliant! Thanks for your knowledge! Some of wich is mine now.....:)
It would be nice if you can get the transformer laminations apart.
Taking the transformer out and removing any bolt through clamping or shell.
I'd be tempted to see if it was possible to use a heat gun or butane torch to
really heat the laminations up. Not burning it though - definitely a bad idea!
With any luck it'll just be varnish holding the core together.
Tapping a strip of metal against the outer lamination pieces and getting one to
move out is a sure win!
Bravo ! ...excellent travail !
Nice work mate
Very good! I have a Philips vacuum tube radio (1950's )
that I have to rewind the power transformer.....
Why does having an insulating layer every 500 turns help (other than to provide physical flattening? Is there some reason there is more voltage difference between 499 and 501 than any two other layers?
Nice winding rig!
Thanks. I was somewhat determined to repair it.
Very resourceful! Well done.
can you get some plans on how to construct that winding jig?
Thank you.
nice work
Congratulations. Not an easy repair to pull off!
Great video!
Good job !
Just ran across this video and must say: Hats off to you for this repair!
Every time I tried to take apart one of those Xfmr's, it seemed impossible to get the core apart!
Would be interesting to know if the scope still worked after this 10 years have past.
I have a SB-610 (?) Heathkit monitor scope that has the HV open but I may just try to use a HV strobe PS to keep from rewinding the Xfmr!
If I lived by you, I'd bring it by--LOL!! 73...
Your Heathkit SB-610 definitely sounds like it is worth repairing.
I wish you good luck with it. Maybe setup a search on eBay for a Transformer kit?
My Hameg scope still works. But I have to admit to mainly using a couple of modern Digital scopes now.
European power transformers seem to be notorious for shorting out. I wonder why. I see it in old radio equipment a lot. Grundig, Telefunken, Majestic, Pye, etc.
I looooove HAMEG products so much.They are really authentic design and manufacturing quality.
Nice work, and lovely clear little movie, all details - xcept - did you feel how warm (if at all) your nice new transformer ran after a few hours? Thanks Anthony in Gloucestershire
Brilliant!
cool winding machine
Brilliant! How do you maintain back-tension of the wire-spool?
The combination of the wire spool suspended on the wooden rod and the wire running through a mechanical pencil. Provided just about the right tension.
Fantastic!
Awesome! I love it.
Fantastic rebuild. Are you using the Nokia 800 or 810? Is it linked directly to the Arduino or the PC controlling the Arduino? Thanks in advance.
HI nick what size wire did you used and how many amps dose the HT pull cheers
does anyone know where to get these film- like cores for DIY expiraments big enough for a 120 volt output? i understand most of this kind of stuff,, ive seen ferrite ones about 2 inches big but thats it. any advice?
How can anyone find a short in the exact spot on enamel wire?
+Joseph Nicholas I'm not sure if you're asking in relation to a spool you can unreel. Or wound up in a transformer. For the Former (pardon the pun) you could unspool the reel onto a new reel while passing it through a metal tube. While charging the wire and tube with some HT. Any weakness in insulation would reveal itself as it passes through the tube.
Finding a short in a 50 or 60Hz transformer, it gets hot, keep unwinding until you get to the arc damage.
+Nick Norton Thanks for this explanation, you obviously have extraordinary patience and skill.
Love the neat Transformer Winder. The all mechanical one at the Technical University in Hannover Germany, used for similar jobs, was the size of a small lathe. Did you find out why the transformer got cooked in the first place?
I bet the one you saw in Hannover was impressive. The transformer got cooked just because the winding shorted. Lots of volts and too little insulation. I still have the same Oscilloscope today. But I do have a fancy pants Digital one to sit with it.
Damn, that was impressive!! Subscribed :-)
Great job, wish I had your setup when I rewound a 25 H choke by hand !!! Question, what is the purpose of adding tape every 500 turns ?
73 N8AUM
The tape at every 500 turns is to avoid having too much voltage potential solely reliant on the thin enamel coating for internal winding insulation. Congratulations for your 25 Henry Choke.
what do you use to edit videos, and what was that effect around 14'21''?
thanks
Hi, I use Kdenlive to edit videos. The effect around 14'21'' is a fade transition between two video clips.
Can you tell me how to fix my blown transformer is outputs 6volts and inputs 120 volts i connected the output wire wrong and one wire sparked inside the transformer and it never worked again thanks in advance
shandev indoi The 6volt secondary may have blown open circuit near the surface of the windings.
You'll still need to do a bit of investigating. Carefully removing layers of tape to survey the damage. Good luck.
ok thanks for the reply do i have to connect the wire and tape it for it to work thanks.
i have the same scope , ive noticed it has some interference , just like youres there , is that from Fluorescent lamps . I dont have probes , butt some my self just for simple use
+Pavle Pavlovic The almost sinusoidal interference is merely 50Hz mains pickup. The input to your scope is quite high impedance. 1 megohm with a x1 probe. 10 megohm with a x10 probe. I'm sure you will have seen just how many volts you can inject into your scope just by touching the probe tip.
Shorting your probe to ground or a low resistance source would yield no noise.
Nick Norton a lot of noise , i was wondering is it becuz i have no probes or is it cuz my built probes are bad , would it be there if i had probes , looks like it would
+Pavle Pavlovic probably bad filtering
I know I'm late with comment, butyo me seems to be problem of not having isolation tape between certein number of turn (between layers).
Your observation is correct. At 1:10 I say there is not enough insulation between layers.
I have that same oscilloscope! What caused transformer burn? Internal shortcircuit or overload caused by something?
Just an internal short in the winding caused by its insulation breaking down. Yours by now, will probably carry on working forever.
great vidio bro i just wondering is that a phone you using as a counter ?how did yo do the seting or,is there software installed in that phone
The Arduino reading the opto sensor and controlling the stepper motor. Is connected to a standard home network Linux PC. The Nokia N900 phone is also connected to the same network via it's WiFi. I'm using the phone with an SSH terminal connection to the Linux PC. Running cat /dev/ttyUSB0 just to show what the Arduino is sending over it's RS-232
So the only software on the phone is just SSH
i am rewinder for 3,a phase motor and i never have experience for rewiding., transformer i am searching how to rewind transformer and i found your vidio so ireally apreciate it
Good job,where did you buy this arduino thank you
store.arduino.cc
or Ebay, Amazon
Hi do you take on jobs, I have a USA cd player the my mate put through a UK voltage through and blown the transformer could you repair this?
Zerocool536 You might be lucky with your transformer. It may have a thermal fuse partially buried in the transformers insulation. If you can dig it out, you may be able to replace it.
The expected output voltages may be fairly common such as 15v - 0 - 15v & 12v so you may be able to pick up a suitable transformer from ebay.
I'd love to help but lack spare time.
Hi
I am Marcel, and i need some help to repair an hameg 408 scope.If you think you could find some free time to this, please let me lnow, and i will send you some pictures with the screen when the scope is on and i will explain what is the work i made to make it start. Thack you very much..
I'm guessing you have taken a look at your manuals at www.rohde-schwarz.com/uk/search/hameg-archive_229476.html?term=hm408
I will take a look at your pictures of the screen. Upload your pictures to something like postimg.org it's free and no account required.
thancks,for respond me so soon..I will try to send a few pictures i have in my phone, because i am not home untill 1 th o march.
Because it didn.t turn on,first i started with the power supply,and i found a coil of the filter open, and i put a wire on the back side . The power supply start, and i could measure all the output voltages , but the scope didn.t have HV voltage for CRT.I change the D615 diode (by509), and the scope start.But is still having problems:1-No brightness adjust 2-the wave of the first picture , depending of the Vertical position scale(it became a line,but only on the highest values of the vertical adjustment scale,AND put closer a Velleman 40 mhz digitaal scope,i could see on the screen the same wave like on hameg .)and 3-the XY mode,it showing me what you see in the second and the third picture.(it is not phone flash..)The schematis is hm 408, not hm 408-1a. Thanck you again.
I've done a few of those kits when I was an apprentice working for a rewind engineering shop. Did you put epoxy on the windings to stop vibration of the turns and the eventual failure of the winding due to shorted turns?
Ugh I wish someone sold transformer kits again. Maplins doesn't sell them anymore.
(Preferably a big transformer kit, like for a 1kVA transformer. I need a bunch of different taps :P
+Benjamin “Ozias” Esposti We used to buy ours from RS Components.
Can you not try to take a 240/110 safety transformer apart and see if that is rewindable? I've rewound loads of transformers often I had to make a new former as they were so badly burned they would fall apart as you were unwinding them to count the turns.
You might get lucky finding a 1KVA transformer that is bolted together and varnished. With some heat perhaps you can knock some of the laminates out. With one out, the rest shouldn’t be too tricky.
stephen dwyer
I can see why you would think it was under rated. But this is not the case. The transformer I wound powers the EHT and bias to the CRT. 5 watts required. The transformer failed not due to normal power demand but due to the EHT winding developing a shorted turn. The existing transformer and the one I wound do not develop any discernible temperature rise above ambient in use.
Why not just get a new oscilloscope? There are some bargains out there. I just threw my old one and replaced it with a new digital. That has been serving me quite well. And it is concideably smaller. And in addition to that it also connects to my computer! Well maybe you needed something to do...?
I enjoyed repairing it. These days I do have a DSO but see no reason to throw out my old scope
+Nick Norton Yes, I see. And you loved doing it too, I could tell. Btw. are those 'do it yourselves' transformers still available?
How much time did this all take?
+Jeffrey Morrissey Best part of the day I think. I remember going to Maplin Electronics to buy a spool of 40SWG wire because I didn’t want to wait a day or two buying it online.
Pure hacker geekness!!
dude wat
except for the enjoyment of rewinding yourself' any reason why you didn't just buy a new transformer ?...it certainly couldn't have been the cost.. nice job though'
Hi Bob, Good question! It's not a generic voltage off the shelf transformer though.
The previous owner did contact Hameg back in 1996/7 and was quoted £90.19 including Tax but not postage.
Neat, jobs a good'n :+)
Funny how Brits pronounce the letter H.
Howdy 😉
thats great, but cheating. you havent lived mate till youve baked a transformer in the oven, got all the bitch off , then rewinding by hand!!!!!!. modern tech. nice one and interesting. well done