Defibrillator teardown

An automatic defibrillator gets taken apart and analysed.
If you want the flipdot indicator, search ebay UK for flipdot

[@terrycollingwood5512]

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.

[@Afrotechmods]

Brilliant idea for a teardown!

[@Bocheno]

Yours teardowns are second to none Mike, keep them coming.

[@wisteela]

Very interesting, and that flipdot is brilliant. Bonus points for the amusing ending. :-)

[@davida1hiwaaynet]

LOL at the end! Your analysis of the circuit is great, thanks for taking the time to trace it out like that.

[@jonp5368]

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

[@bikingmnviking3801]

I had paused that yesterday on the schematic at the end then today it started playing, HILARIOUS ending! Two thumbs up.

[@dfw0204able]

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.

[@unknownname12345]

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.

[@michaelhaley6767]

⁰

[@anthonyvolkman2338]

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.

[@mikeselectricstuff]

@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

[@boonedockjourneyman7979]

Great way to draw reasonably complex circuits. I learned something there.

[@roberthorwat6747]

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.

[@IndustrialGoblin]

Thanks a lot for this teardown! It's like a New Year's present :))

[@vk3crg]

Fantastic that those few electronic components can save a life. Those automatic units are a great invention.

[@meepk633]

The automatic readiness testing is so cool.

[@AintBigAintClever]

Good tip about sawing the back of the Torx bits for accessing deep screws :-)

[@scottyfixit]

Great information! Loved the comical part at the end too!

[@TheCrazyInventor]

Awesome, I love the ending. :D I also like the diagrams with the stick figure. You've put quite some work into this video.

[@Fatkuh]

Very well made infomrative video! Keep going, I like it a lot!

[@KoreanMeatball]

Okay, That bit about cutting into the bit is just genius.

[@ki4soy]

the cutting a slot in the back of bit is brilliant

[@christopherleubner6633]

Wow the guts of this one is very similar to a powerlight camera flash. ❤

[@mikeselectricstuff]

@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!)

[@SproutyPottedPlant]

That was interesting and cool!! You have a new subscriber, Aussie50 sent me this way :)

[@mikeselectricstuff]

@robot797 changed my mind - search for flipdot on Ebay UK.

[@RPBCACUEAIIBH]

The animated symbol of the patient is great... =))

[@hla27b]

nice one Mike thank you

[@ZeedijkMike]

Love the ending. And the test too (-;

[@JaredReabow]

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

[@mikeselectricstuff]

@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.

[@mikeselectricstuff]

@douro20 No - looks flow-soldered.

[@mikeselectricstuff]

@turbochargedbrick I did, but as I didn't have the correct battery, with its ID chip, it didn't do anything.

[@mikeselectricstuff]

@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.

[@doctorgarner]

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?

[@user-qf1rk3oo7y]

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

[@prasannarn946]

What component in the circuity protects the emergency responder from getting shock?

[@NightWolfx03]

Man I wish I had some of the tools you got.

[@randacnam7321]

Those capacitors look like Sprague powerlytics.

[@billwilliams6338]

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?

[@NickNorton]

Interesting teardown, funny ending.

[@jerremm]

This exact eefibrillator, but in blue, was used as a prop in S05E02 of Breaking Bad.

[@todkapuz]

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 :)

[@Maxxarcade]

What do you use to draw your schematics?

[@CxC2007]

very interesting.

[@Serostern]

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

[@Luigi90900]

You know those little cylinders on cables that are for RF filtering, what are they called?

[@TheEPROM9]

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.

[@DrTune]

+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)

[@ANDREYgrava21]

could you make more videos on medical equipment....it's very interesting

[@FyberOptic]

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!

[@thecomputerwhiz1250]

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!

[@mikeselectricstuff]

@robot797 No room for more tubes - email me with a cash offer (Paypal only).

[@danijel124]

what are the main cap ratings?

[@theedrstrangelove]

And I thought opening up my 1971 Ampeg V-4 amp head to recap was frightening!

[@BigAl1048]

- the Rx ikon means by prescription only

[@douro20]

I'd like to see a Heartsine Samaritan- apparently it's the world's most advanced AED.

[@robot797]

@mikeselectricstuff what do you need i got many tubes and can get many old devices (and i has money)

[@douro20]

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.

[@pgqneto]

Could you please find a Transcranial Magnetic Stimulator (TMS) and make a teardown of it for us? or build a TMS prototype.

[@mikeselectricstuff]

generally called flipdots - flipdots.com is one source

[@Mastertim2006]

i have no idea what you are talkin about. but it looks interesting

[@TheLawnWanderer]

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

[@ArduinoTronic]

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.

[@ChrisFredriksson]

@21.36 ... WHAT HAVE YOU DONE!? Mike.. you ba..*grrr*... Poor patient there, poor poor patient!

[@usoppbarbosa981]

Watching this on tax day.. 30s in "... they show you where to stick it..'"

[@douro20]

I would imagine that all of the through-hole devices on this were soldered by hand.

[@wincywillis8758]

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!

[@bikingmnviking3801]

+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". )

[@mikeselectricstuff]

@Zed1967 Someone's already done something along those lines - google "defibrillator toaster"

[@dtiydr]

A defibrillator (guess modern ones are similar) containes A LOT more electronics then i thought..

[@paulevans4334]

What size are the caps ?

[@christopherleubner6633]

The end 😂😂😂

[@dbc1702]

The Rx Symbol is the American Version of our Prescription only Sign

[@shaneavery7235]

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.

[@robot797]

can i buy that flip dot thingy?

[@4211video]

Yeah. It would have been a lot more comfortable to watch if he said up front "I've already discharged all the caps".

[@Jaredo66]

lol @ the end :D.

[@RandomInsano2]

It's a giant speak and spell!

[@TheStevenWhiting]

Serial port is for downloading the persons soul into the PC :) (I'll get my coat)

[@mattmoreira210]

Just a moment. Did you say "gate of the varistors"? Unbelievable.

[@mdesm2005]

It's good stuff, but I have to take a break every few minutes to catch my breath...;)

[@pcuser80]

80186 cpu?

[@bytmeh]

19:11 he's not looking very well because hes about to have a claw jammed where the sun don't shine! ;)

[@medic7038]

400 joules = approximately 5000 volts at 50 amps in 5 milliseconds

[@kokakoka4]

he is my idol xd

[@medic7038]

ROFLMAO 21:48. Oops, LOL often get the ambulance haphazardly left in disarray.

[@ath2698]

@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

[@HDXFH]

It's got USA Made caps!

[@ascii211]

Use that to drive a RAILGUN!

[@ebbcorepairs3253]

So much technology to fail when its needed.

[@wolfy9005]

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.

[@tolgaturhan2069]

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.

[@thebigmacd]

Notice the electrodes were 4 years out of date...you wouldn't want to use it.

[@josealvarez7126]

Internal defribilator

[@laharl2k]

those caps......whould look good on a railgun

[@deviluzaairdbz99]

Breaking Bad. :D (Where are my up thumbs?!)

[@ICanHasSmash]

You kind of look like James May.

[@turbochargedbrick]

Pitty you didn't try to power it up!

[@haruhisuzumiya6650]

They beep

[@jldragicevic]

Good job, 3 people died because they were missing a Defibrillator

[@engribrar1806]

Make a complete video how we repair anesrisa and patient monitor and medical ventilator

[@MoesKeckeEcke]

Feritecore Filters

[@mikeselectricstuff]

@robot797 Make me an offer