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Help! Repairing water damaged PCB from Massage chair.

Discussion in 'Troubleshooting and Repair' started by Jonawald, Dec 16, 2015.

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  1. Jonawald

    Jonawald

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    Dec 16, 2015
    Will have to wait till after noon to do more measurements. I get 12V at regulator but 16.8V at the other points.
    PC270038.JPG
     
  2. Jonawald

    Jonawald

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    Dec 16, 2015

    Yes I replaced those electrolytes. The originals got angry at me when I plugged in the 50V lead there. Threw them out because I can't have their stinking attitude on my boards.
    It was the first time I ever powered up the board. Late at night in the with a lamp because the wife was already in bed. The angry cap woke here up. Had to open window for a while. Adventures adventures. Whoever thought of having two unmarked connectors like that fit the same plug. Next time check the voltage before doing anything silly.
     
  3. Jonawald

    Jonawald

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    Dec 16, 2015
    Something is definitely off with those two voltage regulators. The 7812 has 5V and the 7805 has 12V. I even pulled out the 7805 to make sure I wasn't on something when I put it in. PC270039.JPG
     
  4. Jonawald

    Jonawald

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    Dec 16, 2015
    PC270039.JPG Ok I fixed that. I moved some arrows around. :)

    That has me stumped View attachment 24040 . Why would the voltages be completely different when I put the ground where the second image shows and probe with the red?

    Edited to fix arrows on image.
     
    Last edited: Dec 27, 2015
  5. Bluejets

    Bluejets

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    Oct 5, 2014
    7812 same connections as 7805.
    Common, black probe.(ground)

    Attachment (24040) not working

    It would not be a real concern for me at the moment but at some time when things start to work, I'd be inclined to chuck those relays. My bet they won't be worth a cracker.
     

    Attached Files:

    • 78XX.jpg
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    Last edited: Dec 27, 2015
  6. Jonawald

    Jonawald

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    Dec 16, 2015
    There is no attachment 24040. The forum seems to create that error when I go back and edit pictures after I click post.

    I can demonstrate that all tat is missing for the relays to work is a signal from the CPU. I am beginning to worry about that thing.

    PC260037.JPG
     
  7. Jonawald

    Jonawald

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    Dec 16, 2015
    I disconnected the ribbon from the Mains board and took some readings from the connectors to these transistors. Here are the results. PC270040.JPG
     
  8. Jonawald

    Jonawald

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    Dec 16, 2015
    Is it possible that part of the CPU is fried? or is it an all or nothing deal? I had it on the chair today and tried different programs. The air bag massage works perfectly and one of the vibrators works. I am not sure how the remote works. Does it have it's own CPU, memory and program or does it run from the main CPU on the board? All the programming in the remote seems to work. When I push the different massage options, the proper icons come on on the display. When I hit the various vibrate buttons. the vibrate icons come on in the different parts of the body icon on screen.

    The only thing that seems to work properly on the board with the Mains in and out is the air pump. That works because the air pump for the air bag massage works.

    Right now I am stuck for ideas. I cannot think of another think to try here to get anything working. Any ideas for me?

    I am beginning to think of taking an Arduino and programming it to replace the CPU on this chair. But that's a completely different pile of worms. Even with that, I would need all the circuits working properly away from the CPU.
     
  9. Bluejets

    Bluejets

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    Oct 5, 2014
    What are the red and black arrows?
    Assuming they are your meter probes, it is common practice to measure different points with reference to ground as common (black lead).
    i.e. black lead remains on the ground connection during all voltage measurements otherwise it just becomes too confusing and not much point anyhow as it mostly tells you nothing.
    That board really is a mess and only suggestion I can make is as it appears to be a single layer board, i.e. all traces on the one side and accessable, check out the continuity of each track from point to point.
    Forget the Arduino route for obvious reasons.
    Unless you've blown something up the IC should really be ok but it has many legs into a socket as far as I can make out. Good chance of a crook contact somewhere given it was under water and since corroded there but overall only looking for the obvious really.
    You've certainly taken on a hard one there.
     
  10. Jonawald

    Jonawald

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    Dec 16, 2015

    You are right. The black arrows mean Black lead from Multimeter Red means red Lead.

    Ok Fair enough. But in the case of Post #87, all that does is make put a - in front of the numbers given. If we consider post #83 there is a real problem. Why are the voltages completely off? Why are the numbers what they should be in Post #84 when I turned around and let the Red lead sit and moved the black around? Somebody clear this up for me please.

    Jonathan
     
  11. Jonawald

    Jonawald

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    Dec 16, 2015
    Ok. I cleared up my above question for myself. for Post +84 when I let the Black lead sit where the red was and move around the red everything make sense. I was just holding the black at the wrong spot in post #83.
     
  12. dorke

    dorke

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    Jun 20, 2015
    Yes, measurments should be done with the black lead at GND.
    The regulators are fine.

    The marking on the PCB connectors "12V" is not correct, since it is taken from the unregulated voltage which also feeds the 7812 to create the regulated +12V.
    For the 7812 to operate properly it as to have a voltage input of at least 15V, so 17V makes sense.
    The design of the board with 12V relays connected to 17V is thus not good,
    but that is another issue...;)

    Looking at post #86.
    I understand there are 3 relays which work properly i.e "click" and just one that doesn't .
    Can you please check the voltage to GND on the connector to the controller board,
    when the relays click and when they release.Do the same for the one that dosn't click.


    About the electrolyts,why did you use 2 instaed of one?
    If you go shoping,
    Better use one Cap with same values(C and V and Temp) and size.
    Also,get some s8050 Trs. (or equivalent).
     
    Last edited: Dec 28, 2015
  13. 73's de Edd

    73's de Edd

    2,848
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    Aug 21, 2015
    Sir Jonawald . . . . .


    I'm coming in waaaaay late on this post but I will give my evaluations on the best photographed board that I have marked up , and would only be able to make out more if having its foil side straight on, and about the same size and with minimal lighting reflections.
    If I remember right you were initially coasting right on along until you blew/zap/banged up some of the boards foil paths and that both the marked up RED and YELLOW boxed areas are now non functioning.

    The RED portion is responsible for activating a DC motor driven linear screw actuator that lifts the leg support portion of the unit up or else, lowers it down.

    The YELLOW portion is responsible for the elecro-mechanics activation for the back support position.

    Lets look at the YELLOW BOXED . . . .back up/down associated portion of the photo:

    CN10 routes in a raw AC supply voltage in the order of ~ 12VAC, when loaded down and it passes to the left to the Full Wave Bridge of 4 discrete power diodes and they produce ~ 12VDC when properly loaded down, and since I see no filtering capacitors placed nearby, that resultant pulsating DC might work if a bit of motor hum is permissible.
    The DC power flow from the FWB anodes (-)and cathodes (+) is designated with the +- DIAMONDS, over to the two relays.
    Far left on the block diagram enclosure, are two relay driver transistors being actuated by the control electronics to properly activate the relays associated switching actions so that the DCpower polarity at their associated CN3 power output connector can be polarity flipped in accordance whether the motor run direction for its linear actuator needs to lift or lower the back rest.

    The same action is produced by the boxed in RED area, except it is dealing with 12 VDC power output at CN4 of proper polarity to run the associated Leg Up Down motor of its linear actuator in the proper direction.

    Since you can make all 3 BLUE relays make-a go clicka-clicka, but not the BLACK one you need to be sure you get your GROUNDING lead of your meter correct by connecting it to one of the common tied together emitter connections of the 4 relay driver transistors.
    Then you meter the DC collector voltage of the relay driver transistor located at the side of the BLUE "B "relay" taking and logging down readings with the relay activated and then non activated.( That gives the voltage swing parameters of a good working relay)
    Move to the BLACK " A" relay driver transistor just above and try for the same activation procedure, but as you said no clickee-clickee . . . .but we want to see what its unactivated voltage on its collector is, and it then MAY exhibit some degree of voltage when TRYING to activate itself.
    Therefore, we want to see if it is replicating or trying to replicate the differential voltage reading swings of the "good " BLUE relay just tested.
    One possibility is the relay coil, as Sir dork . . . . .I believe . . . . had marked up / by circling the FUZZY coil spec and it appears to be a 24V coil vice the others 12V coils.
    Now SINCE you can easily read them, see if the sides of the BLUE ones show 12VDC coils while you confirm that the BLACK one has a 24VDC coil.
    Usually a 24V one can marginally activate on 12V, but you would want a match with the other units coil wise.

    The other MAJOR ingredient in the mix, is that you want to confirm that 12VAC is coming in to CN10 and CN11.

    Also you want to ohm out the unplugged connectors to CN4 and CN3 down to the motors and confirm continuity of a motor being on each end.
    Better yet if you have a 12VDC powered portable electric drill *** steal its power pack and use clip leads to run the motors to confirm that they are not locked down by water induced corrosion of their screw drives.
    (*** Or the 12 V battery off yer Harley or from Mamma's Mercedes )

    Walking on down that board, at its center, I am seeing an optisolator fed switch mode power supply with its power output.
    Just below that supply is a replicate but additionally kicking out 12VDC @0.5 amp at a central 5 pin connector.
    Then at the very bottom of the board, I am seeing 4 driver transistors to 4 opti-isolators to feed further over to some Triacs for a heaters temperature control, a pumps control, an AC motor and possibly some control valves .
    All of those functions, I think that you said were operational.

    Sooooo . . . . . . . . its just the motor driven linear actuators that are now lacking functionality.



    ah . . .Mon ami . . .le Techno - Referencing:

    [​IMG]





    Thasssit . . . . . . talk to me . . .and I will additionally show you how to properly repair the units botched up power foil busses, IF its other repairs, end up being are successful.

    Pee Ess . . .You certainly getting mo' bettah at your soldering expertise and particularly . . .flux clean up !

    73's de Edd

    .
     
    Last edited: Dec 28, 2015
  14. Jonawald

    Jonawald

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    Dec 16, 2015
    Will do.
     
    Last edited: Dec 28, 2015
  15. Jonawald

    Jonawald

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    Dec 16, 2015
    Taking the measurements after the relays reminded me of why I went in there to take out diodes in the first place. Take a look at the readings. Black arrow is - probe red arrow is + probe.

    Also, I still cannot get relay A to click despite putting back the original blue. I swapped relay B with A to check if A would click in that position. It does. I pulled, inspected and verified everything in the red oval. I still cannot get that relay to click like the others do. A couple of things to chew on.

    Light is good right now so I was able to take some pictures without flash. I will use these for reference and try to make an overlay so that the foil can be seen. PC280047 copy.jpg
     
  16. dorke

    dorke

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    Jun 20, 2015
    In order to know if the "on-off relay commands" arriving to the board,
    all you need to test are the following simple DMM VDC tests(4 in total):
    In the pic:
    black is the DMM - (GND)
    Reds are DMM + : "1" is for the good clicking relay, "2" is for the "Bad", not-clicking relay.

    When a relay is in "no-click state" VDC should be max 0.7V.
    When a relay is in "click state" VDC should be min 2.0V.
    Please do the measurments and let us know the results.

    Realy-test.jpg
     
    Last edited: Dec 28, 2015
  17. dorke

    dorke

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    Jun 20, 2015
    "Taking the measurements after the relays reminded me of why I went in there to take out diodes in the first place. Take a look at the readings. Black arrow is - probe red arrow is + probe. "

    That measurment should be done as in the pic below.
    Note that in order to get a correct voltage reading you need to activate " BACK" or "LEG" (direction up-down is not importanat).
    and it should be there even with that "unclicking relay activated".
    You already know it is high-voltage,so take care while measuring.
    If you do the same measurment on CN13 up/down would cahnge the readings polarity.
    When you try the measurment on CN14 the "unclicking realy" should give a diffrent reading (LEG-down),while the LEG-UP should give a good reading.


    MOTOR VOLTAGE.jpg
     
    Last edited: Dec 28, 2015
  18. Jonawald

    Jonawald

    196
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    Dec 16, 2015
    0 VDC. No voltage change when I push the leg/back up or down button. Remote makes its cheeping sound as if it was moving the parts, but no voltage change.
     
  19. dorke

    dorke

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    Jun 20, 2015
    Your post is not clear.
    Are you getting 0v only at the bad un-clicking realy?
    If so,what do you get at the good one?(2 readings).
     
  20. dorke

    dorke

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    Jun 20, 2015
    Let's do an ohm continuity test.
    0 ohms, if there is continuity .
    Do the test in DMM ohm range(buzzer if there is one ).

    Between same color points (one on IC controller,the other on resistor):
    Green is a "good relay channel" ,pin #9
    Red is the "Bad relay channel", pin #10
    Do it like the pic shows(on the components legs).
    cable connected between the 2 boards.
    No power!
    what do you get?

    Click-ohm 2 boards.JPG
     
    Last edited: Dec 29, 2015
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