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  1. dorke

    Help! Repairing water damaged PCB from Massage chair.

    "An OHM test between the res points and ground shows 0 ohms. No connection between them." O.K that means the red points are shorted to GND ! Now remove the cable between the boards , and repeat the test on each board separately (in ohm test,not diode). What do you get?
  2. dorke

    Help! Repairing water damaged PCB from Massage chair.

    "If that is still a bad idea. I was mislead." Yes it is a bad idea,especially so when the board is powered. You see, an ohmmeter created voltage will conflict with the board voltage. Ohmmeter test should always be done with no power! What about the 12V?is there any voltage there? Is there...
  3. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Jonatan , I'm speechless ...o_O Why would you use an ohmmeter to make the relays click? What kind of ohmmeter is it ,your DMM?an analog one? Please don't use the ohmmeter again in future measurements! It is diverting the understanding of what you do and what is going on. I was under the...
  4. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Please show what do you mean ,I can't understand Where do you put the "resistor in" ,what value is the resistor you put? Here is the pic from #86.
  5. dorke

    Help! Repairing water damaged PCB from Massage chair.

    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...
  6. dorke

    Help! Repairing water damaged PCB from Massage chair.

    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).
  7. dorke

    Help! Repairing water damaged PCB from Massage chair.

    "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...
  8. dorke

    Help! Repairing water damaged PCB from Massage chair.

    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...
  9. dorke

    Help! Repairing water damaged PCB from Massage chair.

    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...
  10. dorke

    help designing simple 4022 circuit

    post #7
  11. dorke

    help designing simple 4022 circuit

    You are assuming VCC of 5V. But the CD4000 series can operate between 3-18V ,so the diode drop can be cannceld out entierly(say at vcc=5.7v or about). BTW,The last schematics is the one the OP chose to implement.
  12. dorke

    help designing simple 4022 circuit

    They say there were 20 orginal ones, like Hop said above Heaviside re-formulated them. The 4 Maxwell equations are complicated enough as they are...for me at least.;) and I thought I understood them long ago...:(
  13. dorke

    Help! Repairing water damaged PCB from Massage chair.

    I took a look at the controller board. It looks like the "12V" comes from the unregulated part of the PS on it. Can you please confirm. The 2 Electrolytes are replacments you did? What is writen on the Blue relays?
  14. dorke

    Help! Repairing water damaged PCB from Massage chair.

    First thing is the 16.8V is obviosly wrong,need to check the 12V regulator(3 pins) on the control board. What are the regulator voltages relative to GND? If B-E is 16.8V the transistor is bad and probably C-B shorted,you can verify this with an ohm test(no power). But first check the voltage on...
  15. dorke

    transistor pairing? or not?

    No,not an "audiophile". I see your point,and it is a well established one. There is merit in the design of very low distortion,pricing is another issue all toghter...
  16. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Have you got deoxit? It can help with connectors cleaning etc. Bed time for me,talk to you tomorrow. Take care
  17. dorke

    help designing simple 4022 circuit

    Hop, When you ask an Electronics Engineering student: what is the most difficult course you took ? the answer will most probably be "electromagnetic fields"... When dealing with "lumped circuits" we are lucky enough to use the basic circuit theory tools. "my experience over the past...
  18. dorke

    dirty waveform

    Well, It doesn't look like regular ringing to me. The "times of reflections don't compute": they should have been much faster in the nSeC range,not as it shows. It looks more complicated look at the pic. The signal low level is strange(op,is this what you expect 3-24v Swing?) The right ring is...
  19. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Your soldering is much better,are you still using the 1mm solder? It will be much better with a 0.6mm one. I did notice a slightly lifted pad on the connector. The Solder paste looks from another era. It could be very acidic,use it for now and clean the residues very well after. As for the...
  20. dorke

    IR Switch Trigger in Specific Setup

    What ever happened to the art button? As simple as it gets,or not...;)
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