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  1. dorke

    help designing simple 4022 circuit

    Yep, Most of all that annoying guy Murphy: "always right"/"I told you so" etc. He sticks his nose in every damn business ,as if it was is own...o_O Seriously, everything ,but everything ,obeys the 4 overwhelming Maxwell's Equations. Absolutely the 4 pillars of our trade:)
  2. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Jona, Can you please repeat what is the current time fault(I can't find it above...). Actually all the S8050 needs checking. I think the upper (2 tr +2 relays) are for Leg and the bottom ones are for back.
  3. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Did you change that relay? It looks like a 24V relay,and I think the "original" blue ones are probably 12V. Is this so? can you check the voltage on the relay coil to gnd? The S8050 NPN transistor near it(marked blue in the pic) needs testing, you can test it in-circuit and compare with the 3...
  4. dorke

    Help! Repairing water damaged PCB from Massage chair.

    What is the value and voltage of the cap? In general ,you can test caps in circuit . It is very important to discharge them properly. please,don't try that yet !
  5. dorke

    LM317 question.

    You can do better by using a multi-trim pot. in the place of R2. Actually split R2 to a fixed part ,and 10-20% or so pot. to allow for the output voltage setting. In this case you can use 5% fixed resistors.
  6. dorke

    help designing simple 4022 circuit

    If you want to save space you can also : 1.Use a sip 8 common cathode diode array 2.Use a common cathode (or separate) Led bar graph array or 1mm Leds ,in any case look for 2ma ones.
  7. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Good Pictures. We need to find out exactly how those chair elements are connected to the PCBs. Can you please try to put it all in a "diagram" . By CS in the previous post I meant the component side of the PCB you soldered and caused the problem you have now (post #41). Knowing them may help...
  8. dorke

    Standard equipment for beginners

    The thing every beginner needs most is Electronics Education I can recommend the book Make:Electronics by Platt 2nd Ed. 2015 there are "free" PDFs on the web... I would recommend not staring at the soldering method. Instead start with a breadborad At the minimum you would need a DMM start...
  9. dorke

    transistor pairing? or not?

    You are leading already...:)
  10. dorke

    Technics CH990E CD Player does not open

    The "power straps" are propriety to each manufacture. You may find something that is compatible from Technics, best thing would be the same model(used). It is possible to repair this, but unless you do it yourself it isn't economical. Care to try? If so,Show a photo of "The plastic mechanism...
  11. dorke

    transistor pairing? or not?

    I can Salsa,can you...:p Waiting for Santa are we? Here I'll convert it for you ...;)
  12. dorke

    transistor pairing? or not?

    steve, Please define "a god result" in numbers.
  13. dorke

    transistor pairing? or not?

    Bob, A scam? why do you say that?
  14. dorke

    Help! Repairing water damaged PCB from Massage chair.

    Yes the other side of the board (CS- Component Side). A service manual will be very helpful. Have a good one:)
  15. dorke

    dirty waveform

    It looks bad enough. a comparator could clean it. but it would be better to clean it at the source. You haven't answered the basic question: what is creating this signal? Have you got the schematics of it? or a photo?
  16. dorke

    Help! Repairing water damaged PCB from Massage chair.

    MG chemi is making good products(unless it is a Chinese fake). I guess you didn't use it properly. The way I do it is wet the iron tip with a little solder and sometimes add flux to the wick if needed. Look at this (mute ) video for how to. So, were do we stand with the boards? You didn't...
  17. dorke

    dirty waveform

    Yes,could be.
  18. dorke

    transistor pairing? or not?

    swagguy, Your previous questions speak otherwise...;) You don't have enough knowledge for this . You may build it,but you don't understand how it works (not only in the finest details). Buying 1000 Tr. and trying to match them? That is a low level hobbyist attitude, miles away from the Pro one...
  19. dorke

    dirty waveform

    Steve,it isn't classical ringing as the final low voltage is at or below the minimum of the "ring" . Also look at this from post 13. Not clear at all.
  20. dorke

    Help! Repairing water damaged PCB from Massage chair.

    What components are on the other side? Can you show on a pic,and what is written on them. On this pic below (from post #40) , bottom right you wrote "ALL work". Is this before or after the above soldering incident? If it is after ,then most probably the Controller IC is fine...;)
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