Electrocardiogram Machine Teardown - The Electronics Inside

I thought it'd be interesting to see what differences we can spot in a medical device? Will it be more robust, better build quality or something else entirely? There is only one way we will find out! bit.ly/2zI4Lu6
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[@zaprodk]

The footprint for the RAM is made that way since the same part exist in two different case styles. This way you are not screwed if one of them goes out of stock when you start production

[@a531016]

I figured it was something along those lines. Thank you!

[@JoshuaPritt]

I never thought of using a 1:1 transformer for isolation. Brilliant!

[@HTMWorkshop]

Ha, I remember that one. We use to have that ECG in our lab

[@wlfgang]

I think Mortara also manufactured same model machines, the only difference if their brand in Europe was called Burdick. Now they're bought by Welch Allyn.

[@briangoldberg4439]

ZIF connectors have clips instead of being friction fit. Thus "Zero Insertion Force." I think that one is just a ribbon cable with what looks like a pin header connection.

[@DaveMcAnulty]

I don't think there is AC being supplied to that logic board. I'd guess that Q8 and Q9 (near the transformer T2) are being used to generate DC pulses into AC for that transformer over to the patient side. I bet that U23 is controlling them. Can't quite make out the last digit of it's part number though. TL594?

[@a531016]

Sorry, I don't have a better picture to hand, I'll dig it out and take a look for you. I assumed it was AC because of the configuration of the diodes on the top center of this www.element14.com/community/servlet/JiveServlet/downloadImage/889713/Diodes.jpg Two one way, two the other looked like a bridge rectifier to me. It could of course be pulsed, and it'd be interesting to know if that's pulsed + and - to 0V on the input or just 0 and + through the transformer?

[@zaprodk]

The caps are safe. It's not a switchmode supply and there is nothing inside the machine that runs a high voltage.

[@a531016]

I'd agree, but every time I don't mention it someone always comments on it! Also, I'd guess it doesn't hurt to be cautious!

[@NiHaoMike64]

Then you come across a device with a plasma display and get a nasty surprise. (At least the plasma display drivers usually discharge the high voltage caps.)

[@DaRUde117]

Can you do a teardown of an ECT machine next?

[@a531016]

Wow - that's a suggestion! Vintage or modern? Also, would something similar be acceptable? AED or tens?

[@DaRUde117]

@@a531016 A modern look would be nice, and I would much rather see a ECT machine not only because I'll be going through the treatment myself but also curious to see how its able to deliver those small currents :)

[@MAYERMAKES]

The German pronunciation is pretty much the same as in english

[@a531016]

Yep, but I was super confused by the difference of ECG and EKG. Turns out there really is none...

[@MAYERMAKES]

@@a531016 sometimes an Elektrokardiogram is just an electrocardiogram

[@wlfgang]

@@a531016 Doctors everywhere like to pronounce EKG because it sounds more normal rather than saying E-C-G. They write it in Anglo countries ECG though everywhere I think. Non-Anglo's call it EKG everywhere. There is no difference. My opinion - EKG is better and closer to original.

[@alexanderlacy945]

You should try to get the thermal printer running stand alone.

[@a531016]

Ha! Yes, we can definately look into that!

[@andrewlavey6992]

Is it safe to assume that an EEG will have similar electronics?

[@a531016]

I would assume so, but you know what they say about that! I'd definately expect similar isolation, what I'm not too sure on is the analogue inputs. With it needing far more sensitive inputs, and the ability to cancel out "pusle" interference?