That was absolutely fascinating. I'm a doctor not an electrical engineer so I didn't understand a fair bit of it but I got the general picture. Really thorough job, nicely presented. Thanks! PS: the little symbol on the bottom with the stick figure is the international symbol for electrical equipment that is safe to be used in the presence of a defibrillator! A little bit tortological in this case but there you go.
@zzzzbest the TH parts are definitely flow soldered - can't tell if auto inserted but due to the wide range of sizes they may well have been hand-inserted
@2009mnasar Panasonic HDC-SD10. Bought cheap on ebay as faulty & fixed it. It's OK - I've no experience of other cams to compare with, but minor complaints are no external mic, no remote, manual lens-cap (it should at least beep if you turn it off & leave the lens open!)
It would be nice if you tried to articulate you words instead of talking inside your mouth at the end of a sentence. This would produce a clear and understanding explanation. You garble to much and talk to fast for the majority of your watchers. I try to give you some direction to enhance you video postings and do not want to be rude or anything else. At least you try and that speaks in your favor but about 50% goes lost in .... Anyway I hope you consider some of my hints. Keep up your work.
That cap/resistor ladder coming off the main power transformer (probably a flyback switching converter and more than likely running in a DCM mode) is used more than likely to act as a resonant circuit, to help damp the inrush going into the caps and also as a decoupling cap to prevent the high DC voltages from discharging through the secondary of the transformer. Otherwise it would short through the transformer and possibly damage it while also harming even the drive circuitry due to it sending a low but extremely high current pulse (that's negative and rings like crazy) out of the primary. Which could damage your drive MOSFETs. They gave GDTs normally (Gate Drive Transformer). The use of resonant caps like this is very common in low power high voltage circuitry such as this. Extremely well done video by the way! Very well explained. I've actually used some of the design criteria of AEDs for my own high voltage capacitively coupled secondaries, it's called ferroresonance, where the leakage inductances of the secondary and the series cap make a complex LC network that allows for higher voltages and also DC decoupling. Also like you mentioned it is a ferrite core meaning that 10nf cap is perfect due to the high frequencies the transformer is being driven at. It's simply a high voltage SMPS but with multiple safety measures.
you so confidently touch the components, without even discharging the caps encase they have some residual current, especially from you trying to power it up
@douro20 Not sure what the requirements are but there's quite a lot of extra logic on the CPU, so I'd expect there is significant reality-checking, watchdogs etc. Problem with multiple processors is you increase overall complexity & make it harder to test. Glad I don't write code for things like this.
i just found this channel. Oh my dear god this is the type of lad ive always wanted to meet and swap tech talk with this is what i do WITH EVERYTHING TEACH ME YOUR WAYS YOU MAGICAL BRITISH WIZARD
Faaasscinaaaatink mein herr!!! We have several of these dotted about where I work. They cost approx £1000 a pop. Did a defib course and got to see a demo with the voice commands and the cycle through the whole process. The speaker is very loud for obvious reasons. Imagine having to use one during a football match at Old Trafford or Wembley. Great tool tip with the slot and a great 'oops!' at the end.
Always awesome, Thanx again Mike. I really look forward to your teardowns. Ive done a few of my own since ive subscribed here. Biomedical engineering, mainly in dental. I get to rip apart some amazing tech every day for the last 18 years. Lots of technology, digital radiology, lasers and such. Even started trying to utilize what i call my modded by mike flir, instead of e4-e8 mines a M4, lol! Keep em coming man, love it.
Hi Mike electric stuff, Why does or where does the leakage current come from in biomedical equipment? when testing biomedical equipment the leakage current is in the microamps but where is the microamps of leakage current caused from what components?
@douro20 You find me one cheap & I'll pull it apart! I'm happy to pay shipping! I think a lot of the defib waveforms and detection criteria are set by standards derived from clinical trials, so not sure how much scope there is for variations other than clever circuitry.
Just a note about the funny end bit, AED's cannot fix a flatline. They will only fix ventricular fibrillation and ventricular tachycardia. Other than that brilliant video!
Rx-only .. in the united states one must have a prescription (rx) to own an aed .. typically to get one (as a business), there basically has to be medical direction and a program (procedure) around the use and care of the aeds. just more of the high regulation of medical devices in this country. the newer version of this product (that we use and im responsible for at my company) actually have 3 different shock levels... neat seeing inside as obviously can't do that for ours and still use :)
Wow. Very interesting design. The designs they teach us are usually just a large capacitor array with the pulse waveform simply inverted midway through discharge (hence the negative pulse starting at the opposite of the trailing edge of the positive pulse). Any idea why they'd go to such terrible complexity of voltage balancing two separate capacitor banks instead of simply using a second array of MOSFET/thyristors to "flip" the capacitor array? BTW: these deliver a very fixed number of coulombs of energy; in debug mode, these will actually give you exact energy delivered. Which portion of the circuitry monitors actual energy delivered? The smaller transformer?
Looking at the type of CPU and the application used I would suspect it would have run some form of embedded Linux, were you ever able to confirm this as I would also not be impossible that it could have run on MSDOS or a custom OS instead.
+TheEPROM9 Seems pretty unlikely IMO - I'd guess it's a simple RTOS - anything else would be pretty over the top for that application (and back in 2000 designers didn't just reach for Linux the way that's so temptingly cheap/easy to do nowadays)
So basically at heart it's a PC. I always love finding devices which still run microcontroller iterations of early chips, particularly of x86. I've usually found V20/V30, but also the occasional 80C186. Z80 hardware seems more common, but it's more prone to end up in proprietary microcontrollers, where only reverse-engineering firmware reveals what the I/O ports control. x86 or not, though, running something like Star Control on a defibrillator is still a bit out of the question!
ive just teardowned a defibrilator. it had a big flyback transformer 3 big relays and a 6kV 32üF cap. wasnt a mobile one it ran on 220v. but was in a mobile orange box
3.2mm PCB's are standard in the front panel manufacturing industry. Some manufacturers are set upfor nothing else and will charge a premium for anything thinner.
I got a set of torx security screws of allen wrench type. (L shape) - they are awesome for reaching down in holes =) The defibs Ive seen they just filled the entire cavity with epoxy :c Nice ending btw =P
@mikeselctricstuff ...sir I m a biomedicl engineering research student from india. I would like to make an defibrltr with low weight and low cost one. I m stucked in my reserach for getting the inernal circuitary of AED. can u pls provide a used or reprble AED for me it would be pleasure, PL sprovide ur contct details
Nope. I'm more worried about using 2 hands with high voltage, but it is clear this guy knows what he is doing so I have no reason to be worried. Most caps can be discharged by simply shoving a screwdriver in between the terminals quickly or using a big bastard of a resistor.
The capacitors in an AED are not charged when the AED is switched off and when it doesn’t have a battery installed. The AED will only charge the capacitors during self tests and rescues on patients. During self tests the AED charges the capacitors to test if they’re in working condition, but after the self test it automatically discharges the capacitors.
Love seeing the teardowns, some great ones and some fantastic info. But please get facts right when describing devices. You have "used for resuscitation on heart attack", what, NO. They are used on Cardiac Arrest, totally different to a Heart Attack, a defib on a heart attack casualty wouldn't do a thing. The defib do not resuscitate, they stop your heart which should then start it going again. Like the bit, designed for people without full medical training like ambulances!
+Wincy Willis Right, they use shots of epinephrine sulfate to start the heart. I remember them doing that after I gave my father CPR. I always wondered what frequency the heart defaults to when it defibs (I once wondered if it was 120 caused by all the 60 hz power around us... and would it be 100 in the UK with 50 hz power?) and why it defibs to that frequency. Excellent video, Mike, 'specially love the schematic at the end... we could build one of our own! ( I almost bought an EKG machine with defib at a garage sale a block over but thought, WHY? Would have made an interesting YT vid.. this thing was ancient. Wooden case. Almost no safeties anywhere -- it was just assumed it be "in the right hands". )
But Computers can make mistakes due to programming error's or mishandling. Well there are always two EMS technician's who can look at the problem and adapt to fix it I have got noting agansed Computers, i work in IT and i love doing it. But when it comes to life or death situation i take a real person.
Funny that the EMS where you live are not trusted with the real Defibrillator's. I am glad that where i live they have the real ones and not these My little Defibrillator toys. I don't think i have trusted that thing when i had to be shocked.
That was absolutely fascinating. I'm a doctor not an electrical engineer so I didn't understand a fair bit of it but I got the general picture. Really thorough job, nicely presented. Thanks! PS: the little symbol on the bottom with the stick figure is the international symbol for electrical equipment that is safe to be used in the presence of a defibrillator! A little bit tortological in this case but there you go.
Brilliant idea for a teardown!
LOL at the end! Your analysis of the circuit is great, thanks for taking the time to trace it out like that.
Yours teardowns are second to none Mike, keep them coming.
@zzzzbest the TH parts are definitely flow soldered - can't tell if auto inserted but due to the wide range of sizes they may well have been hand-inserted
Fantastic that those few electronic components can save a life. Those automatic units are a great invention.
Very interesting, and that flipdot is brilliant.
Bonus points for the amusing ending. :-)
@2009mnasar Panasonic HDC-SD10. Bought cheap on ebay as faulty & fixed it. It's OK - I've no experience of other cams to compare with, but minor complaints are no external mic, no remote, manual lens-cap (it should at least beep if you turn it off & leave the lens open!)
Good tip about sawing the back of the Torx bits for accessing deep screws :-)
Okay, That bit about cutting into the bit is just genius.
@turbochargedbrick I did, but as I didn't have the correct battery, with its ID chip, it didn't do anything.
the cutting a slot in the back of bit is brilliant
I had paused that yesterday on the schematic at the end then today it started playing, HILARIOUS ending! Two thumbs up.
It would be nice if you tried to articulate you words instead of talking inside your mouth at the end of a sentence. This would produce a clear and understanding explanation. You garble to much and talk to fast for the majority of your watchers. I try to give you some direction to enhance you video postings and do not want to be rude or anything else. At least you try and that speaks in your favor but about 50% goes lost in .... Anyway I hope you consider some of my hints. Keep up your work.
That cap/resistor ladder coming off the main power transformer (probably a flyback switching converter and more than likely running in a DCM mode) is used more than likely to act as a resonant circuit, to help damp the inrush going into the caps and also as a decoupling cap to prevent the high DC voltages from discharging through the secondary of the transformer. Otherwise it would short through the transformer and possibly damage it while also harming even the drive circuitry due to it sending a low but extremely high current pulse (that's negative and rings like crazy) out of the primary. Which could damage your drive MOSFETs. They gave GDTs normally (Gate Drive Transformer). The use of resonant caps like this is very common in low power high voltage circuitry such as this. Extremely well done video by the way! Very well explained. I've actually used some of the design criteria of AEDs for my own high voltage capacitively coupled secondaries, it's called ferroresonance, where the leakage inductances of the secondary and the series cap make a complex LC network that allows for higher voltages and also DC decoupling. Also like you mentioned it is a ferrite core meaning that 10nf cap is perfect due to the high frequencies the transformer is being driven at. It's simply a high voltage SMPS but with multiple safety measures.
The automatic readiness testing is so cool.
@robot797 changed my mind - search for flipdot on Ebay UK.
Thanks a lot for this teardown! It's like a New Year's present :))
you so confidently touch the components, without even discharging the caps encase they have some residual current, especially from you trying to power it up
@douro20 No - looks flow-soldered.
@douro20 Not sure what the requirements are but there's quite a lot of extra logic on the CPU, so I'd expect there is significant reality-checking, watchdogs etc. Problem with multiple processors is you increase overall complexity & make it harder to test.
Glad I don't write code for things like this.
i just found this channel.
Oh my dear god this is the type of lad ive always wanted to meet and swap tech talk with
this is what i do WITH EVERYTHING
TEACH ME YOUR WAYS YOU MAGICAL BRITISH WIZARD
Great way to draw reasonably complex circuits. I learned something there.
Faaasscinaaaatink mein herr!!!
We have several of these dotted about where I work. They cost approx £1000 a pop. Did a defib course and got to see a demo with the voice commands and the cycle through the whole process. The speaker is very loud for obvious reasons. Imagine having to use one during a football match at Old Trafford or Wembley. Great tool tip with the slot and a great 'oops!' at the end.
Awesome, I love the ending. :D
I also like the diagrams with the stick figure. You've put quite some work into this video.
What component in the circuity protects the emergency responder from getting shock?
You know those little cylinders on cables that are for RF filtering, what are they called?
Always awesome, Thanx again Mike. I really look forward to your teardowns. Ive done a few of my own since ive subscribed here. Biomedical engineering, mainly in dental. I get to rip apart some amazing tech every day for the last 18 years. Lots of technology, digital radiology, lasers and such. Even started trying to utilize what i call my modded by mike flir, instead of e4-e8 mines a M4, lol! Keep em coming man, love it.
⁰
Hi Mike electric stuff, Why does or where does the leakage current come from in biomedical equipment? when testing biomedical equipment the leakage current is in the microamps but where is the microamps of leakage current caused from what components?
@douro20 You find me one cheap & I'll pull it apart! I'm happy to pay shipping!
I think a lot of the defib waveforms and detection criteria are set by standards derived from clinical trials, so not sure how much scope there is for variations other than clever circuitry.
@mikeselectricstuff what do you need
i got many tubes and can get many old devices (and i has money)
That was interesting and cool!! You have a new subscriber, Aussie50 sent me this way :)
Wow the guts of this one is very similar to a powerlight camera flash. ❤
What do you use to draw your schematics?
Great information! Loved the comical part at the end too!
Those capacitors look like Sprague powerlytics.
what are the main cap ratings?
The animated symbol of the patient is great... =))
What size are the caps ?
Just a note about the funny end bit, AED's cannot fix a flatline. They will only fix ventricular fibrillation and ventricular tachycardia. Other than that brilliant video!
Could you please find a Transcranial Magnetic Stimulator (TMS) and make a teardown of it for us? or build a TMS prototype.
Rx-only .. in the united states one must have a prescription (rx) to own an aed .. typically to get one (as a business), there basically has to be medical direction and a program (procedure) around the use and care of the aeds. just more of the high regulation of medical devices in this country. the newer version of this product (that we use and im responsible for at my company) actually have 3 different shock levels... neat seeing inside as obviously can't do that for ours and still use :)
Wow. Very interesting design. The designs they teach us are usually just a large capacitor array with the pulse waveform simply inverted midway through discharge (hence the negative pulse starting at the opposite of the trailing edge of the positive pulse). Any idea why they'd go to such terrible complexity of voltage balancing two separate capacitor banks instead of simply using a second array of MOSFET/thyristors to "flip" the capacitor array? BTW: these deliver a very fixed number of coulombs of energy; in debug mode, these will actually give you exact energy delivered. Which portion of the circuitry monitors actual energy delivered? The smaller transformer?
@robot797 No room for more tubes - email me with a cash offer (Paypal only).
can i buy that flip dot thingy?
could you make more videos on medical equipment....it's very interesting
This exact eefibrillator, but in blue, was used as a prop in S05E02 of Breaking Bad.
Looking at the type of CPU and the application used I would suspect it would have run some form of embedded Linux, were you ever able to confirm this as I would also not be impossible that it could have run on MSDOS or a custom OS instead.
+TheEPROM9 Seems pretty unlikely IMO - I'd guess it's a simple RTOS - anything else would be pretty over the top for that application (and back in 2000 designers didn't just reach for Linux the way that's so temptingly cheap/easy to do nowadays)
It's amazing that this thing doesn't have master-slave processors. I would think for redundancy that such a thing would be required by law.
So basically at heart it's a PC. I always love finding devices which still run microcontroller iterations of early chips, particularly of x86. I've usually found V20/V30, but also the occasional 80C186. Z80 hardware seems more common, but it's more prone to end up in proprietary microcontrollers, where only reverse-engineering firmware reveals what the I/O ports control. x86 or not, though, running something like Star Control on a defibrillator is still a bit out of the question!
Man I wish I had some of the tools you got.
ive just teardowned a defibrilator. it had a big flyback transformer 3 big relays and a 6kV 32üF cap. wasnt a mobile one it ran on 220v. but was in a mobile orange box
Very well made infomrative video! Keep going, I like it a lot!
i have no idea what you are talkin about. but it looks interesting
3.2mm PCB's are standard in the front panel manufacturing industry. Some manufacturers are set upfor nothing else and will charge a premium for anything thinner.
80186 cpu?
generally called flipdots - flipdots.com is one source
- the Rx ikon means by prescription only
I got a set of torx security screws of allen wrench type. (L shape) - they are awesome for reaching down in holes =)
The defibs Ive seen they just filled the entire cavity with epoxy :c
Nice ending btw =P
I'd like to see a Heartsine Samaritan- apparently it's the world's most advanced AED.
Interesting teardown, funny ending.
A defibrillator (guess modern ones are similar) containes A LOT more electronics then i thought..
Love the ending. And the test too (-;
I would imagine that all of the through-hole devices on this were soldered by hand.
And I thought opening up my 1971 Ampeg V-4 amp head to recap was frightening!
id love to have those caps.
so rare to find large ones like that.
allso caps are very expensive in norway, if you can find them.
XD
@Zed1967 Someone's already done something along those lines - google "defibrillator toaster"
@mikeselctricstuff ...sir I m a biomedicl engineering research student from india. I would like to make an defibrltr with low weight and low cost one. I m stucked in my reserach for getting the inernal circuitary of AED. can u pls provide a used or reprble AED for me it would be pleasure, PL sprovide ur contct details
The Rx Symbol is the American Version of our Prescription only Sign
Yeah. It would have been a lot more comfortable to watch if he said up front "I've already discharged all the caps".
what i do to get the driver down that deep hole the security screws are in is heat up the driver and just sink it in like butter.
Watching this on tax day.. 30s in "... they show you where to stick it..'"
@21.36 ... WHAT HAVE YOU DONE!? Mike.. you ba..*grrr*... Poor patient there, poor poor patient!
Just a moment. Did you say "gate of the varistors"? Unbelievable.
nice one Mike
thank you
Pitty you didn't try to power it up!
Why a defibrillator needs a real time clock?????????
To register the date and time of each use, maybe.
Francisco Herrera Yep - as they say, for logging. The data on use is printed on the output strips and is available in memory for a time afterward.
Exactly. Much more clever explanation than mine. :D
Serial port is for downloading the persons soul into the PC :) (I'll get my coat)
Nope. I'm more worried about using 2 hands with high voltage, but it is clear this guy knows what he is doing so I have no reason to be worried. Most caps can be discharged by simply shoving a screwdriver in between the terminals quickly or using a big bastard of a resistor.
The capacitors in an AED are not charged when the AED is switched off and when it doesn’t have a battery installed. The AED will only charge the capacitors during self tests and rescues on patients. During self tests the AED charges the capacitors to test if they’re in working condition, but after the self test it automatically discharges the capacitors.
Good job, 3 people died because they were missing a Defibrillator
Make a complete video how we repair anesrisa and patient monitor and medical ventilator
It's good stuff, but I have to take a break every few minutes to catch my breath...;)
Notice the electrodes were 4 years out of date...you wouldn't want to use it.
do you have something against automation? computers never make mistakes due to stress or fatigue unlike humans.
Love seeing the teardowns, some great ones and some fantastic info. But please get facts right when describing devices. You have "used for resuscitation on heart attack", what, NO. They are used on Cardiac Arrest, totally different to a Heart Attack, a defib on a heart attack casualty wouldn't do a thing. The defib do not resuscitate, they stop your heart which should then start it going again. Like the bit, designed for people without full medical training like ambulances!
+Wincy Willis Right, they use shots of epinephrine sulfate to start the heart. I remember them doing that after I gave my father CPR. I always wondered what frequency the heart defaults to when it defibs (I once wondered if it was 120 caused by all the 60 hz power around us... and would it be 100 in the UK with 50 hz power?) and why it defibs to that frequency.
Excellent video, Mike, 'specially love the schematic at the end... we could build one of our own! ( I almost bought an EKG machine with defib at a garage sale a block over but thought, WHY? Would have made an interesting YT vid.. this thing was ancient. Wooden case. Almost no safeties anywhere -- it was just assumed it be "in the right hands". )
ROFLMAO 21:48. Oops, LOL often get the ambulance haphazardly left in disarray.
@robot797 Make me an offer
The end 😂😂😂
400 joules = approximately 5000 volts at 50 amps in 5 milliseconds
It's a giant speak and spell!
19:11 he's not looking very well because hes about to have a claw jammed where the sun don't shine! ;)
So much technology to fail when its needed.
very interesting.
those caps......whould look good on a railgun
Use that to drive a RAILGUN!
You kind of look like James May.
It's got USA Made caps!
Breaking Bad. :D
(Where are my up thumbs?!)
But Computers can make mistakes due to programming error's or mishandling. Well there are always two EMS technician's who can look at the problem and adapt to fix it
I have got noting agansed Computers, i work in IT and i love doing it. But when it comes to life or death situation i take a real person.
Funny that the EMS where you live are not trusted with the real Defibrillator's. I am glad that where i live they have the real ones and not these My little Defibrillator toys. I don't think i have trusted that thing when i had to be shocked.
lol @ the end :D.