Author Topic: Need help testing the function of this medical chair controller  (Read 220 times)

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Offline Brathahn

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Hello,
i have this controller board for a medical chair wich i have to test. Unfortunately i dont have any documentation or the chair itself.
As far as i know this board controls some motors via relays to move the chair up, down and in some other directions.



On first inspection there was some arcing on the 230V side and some dead capacitors due to age. easy fix.

Now i want to test this board but i dont know what it does.. so i revese engineered it and drew a schematic:



Im not good with analog circuits like this one and i cannot figure out the function. Can anyone tell me how this thing works?

Thank you!
 

Offline ivi_yak

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Re: Need help testing the function of this medical chair controller
« Reply #1 on: May 10, 2020, 03:03:42 pm »
Hi, pls convert your schematic to PDF and I'll describe you whats going here
eevblog
 

Offline Brathahn

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  • Country: de
Re: Need help testing the function of this medical chair controller
« Reply #2 on: May 11, 2020, 12:06:09 pm »
Hello,
unfortunately i cannot create a pdf that large.
I can provide a bigger schematic if that helps you? The one i posted is already 4700px by 4700px big.
 

Offline Brathahn

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  • Country: de
Re: Need help testing the function of this medical chair controller
« Reply #3 on: May 12, 2020, 03:06:28 pm »
Hello,
my friend made a pdf for me. so here you go  :-+
 

Offline ivi_yak

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Re: Need help testing the function of this medical chair controller
« Reply #4 on: May 13, 2020, 08:37:50 pm »
Hi, first you go you need to restore soldering I'll mark with red. After that apply power 220v to P3.1 and P3.4, be carefully board has no isolation so all staff will be under 220 line potential according to your draw (I'll recommend to use isolating transformer). After that check power of LM342 opamp between 4 vcc and 11 gnd legs should be around 25V. seems R-HL are the signals from safety interlocks which block all outputs of LM342 and turn off relays into some default state. Also A1 connector is some error indicating external led. For further tests you need to connect some loads to relays outputs and apply voltage to P2.5 P2.6 P2.10 P2.1 P2.2 to check relay acting normally.
eevblog
 


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