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Ultrasonic bath

Discussion in 'Electronic Repair' started by Yianni, Aug 13, 2008.

  1. Yianni

    Yianni Guest

    Hi,
    I have a small ultrasonic cleaner. It's frequency is 40kHz, and I want to
    increase it to about 50%. I expect about 15W output. Which parts I should
    change? I suspect the two blue capacitors, but I'm not sure. My knowledge in
    electronics is low.

    Some details: The ic is the 555, for on/off and timer purposes, including
    the relay and the small trnasistor. The above left part (in reference to
    Photo 017.jpg) is the AC input, and the upper part the AC-->DC. The
    transformer drives the transducer. The low part is the oscillator (two
    transistors, some resistors 1 and 1/2W, a few capacitors and two diodes).
    The torroidal transformer I don't know what it does.

    Does anyone know which parts to change? I don't know to change the
    transformer if it needed. I will try with the same transformer. Output
    wattage is not significant.

    http://www.inkline.gr/temp/Photo 017.jpg
    http://www.inkline.gr/temp/Photo 015.jpg
    http://www.inkline.gr/temp/Photo 018.jpg
    http://www.inkline.gr/temp/Photo 007.jpg


    Thank you
     
  2. PeterD

    PeterD Guest

    'it' being frequency? If so, I doubt it: the transducer is resonate
    and would have to be replaced.

    'it' being power? If so, I doubt it: the transucer is only going to be
    able to handle a certain amount of power before failing.
     
  3. Yianni

    Yianni Guest

    I don't think the transducer is so high resonant. At least the specific one.
    On the other hand, I would like to try. Do you know which parts to change?
     
  4. Yianni

    Yianni Guest

    Just to say what I meant. The specific transducer is inexpencive one, most
    like a "buzzer" than a conventional transducer. I have seen some other
    ultrasonic baths involving just a buzzer!!
    I don't care for the power, even if it reduced at 10%.
     
  5. To be a bit more diplomatic :), the OP did supply photos of the PCB.

    But, someone would have to take a fair amount of time to try to figure
    out which parts control frequency from looking at it. "Blue caps"
    don't mean anything - one has to trace the circuit to determine what
    the components do.

    If the OP would do that and post a schematic, or even a partial
    schematic, then someone should be able to help.

    --
    sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
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  6. PeterD

    PeterD Guest

    Your first three words are correct. The remainder of the statement is
    not. It is very resonant.
     
  7. PeterD

    PeterD Guest

    Horse... Dead... Beating... Stop!
     
  8. Yianni

    Yianni Guest

    Thank you for your reply.
    You are right. I tried to find the schematic on internet with no luck. If I
    try to trace the schematic it will take much time, because I don't have much
    knowledge in electronics, none in oscillators. For me, it will take two
    days... I'm sure, you know, someone without knowledge may needs 20 or 50
    times more time and effort to find what he wants.
    If you could guide me to trace a very small part, I will.
    The model is the CD-2800, CODYSON (China) is the manufacturer.
    The only info I found on internet are the following. I don't know Russian, I
    tried to register but it has a quiz of 15 questions:
    http://www.mcrf.ru/forum/showthread.php?p=123710
    http://www.mcrf.ru/forum/showpost.php?p=128953&postcount=228
    Registration --> http://www.mcrf.ru/forum/register.php

    p.s. If the above forum has the schematic, may it worth to find it first.

    --
    Yianni

    (Remove the number nine from my email address to send me email)
     
  9. Franc Zabkar

    Franc Zabkar Guest

    Is there is a patent reference on the label? If so, then you can
    sometimes find a how-it-works explanation at ...

    http://www.uspto.gov/patft/index.html
    http://www.freepatentsonline.com/search.html

    Here are some examples:

    OSCILLATOR CIRCUIT FOR AN ULTRASONIC CLEANER
    http://www.freepatentsonline.com/3584244.html

    http://www.freepatentsonline.com/5109174.html
    http://www.freepatentsonline.com/5534741.html
    http://www.freepatentsonline.com/3937236.html

    If you read the text of the various inventions, it appears that they
    all use a 40kHz piezoelectric transducer driven by a two-transistor
    oscillator. One patent states that "the oscillation frequency is
    dependent mainly upon the characteristics of the piezo element". I
    think what you are trying to do is akin to changing the natural
    oscillation frequency of a quartz crystal by playing around with
    external components, ie it makes no sense.

    - Franc Zabkar
     
  10. Yeah, I despise those sites..... Although in all fairness, some have
    useful information or downloads.

    Whether they have a schematic? Could be, but it could just be someone
    else asking....

    There's probably a pair of power transistors or MOSFETs that's a power
    oscillator. If you trace around that area, it could help. But
    no guarantees. But assuming it is resonant, that may be part of
    what determines the frequency.

    --
    sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
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  11. Well, he could go lower by adding mass to it. Higher? Chip off a piece? :)

    --
    sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
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  12. Ken G.

    Ken G. Guest

    What are you ``ultrasonicing`` ? With todays good cleaning products i
    use my ultrasonic way less these days
     
  13. Franc Zabkar

    Franc Zabkar Guest

    In all honesty, I was going to suggest something along those lines,
    assuming it is at all feasible. Years ago I had a problem with a 25MHz
    crystal that had begun to oscillate at a higher frequency (not an
    overtone). I suspect that either a piece had chipped off as a result
    of an accident, or maybe a dag that was present during the trimming
    process finally fell off in normal usage.

    Alternatively, the OP might try procuring a ready-made replacement:
    http://www.annon-piezo.com/product/PZT-Transducer-cleaner.htm

    For example, the ANN-2560 is rated at 59kHz and 25W.

    - Franc Zabkar
     
  14. Dave W

    Dave W Guest


    WHY do you want to increase the frequency?

    Dave W
     
  15. We don't even know what he wants to do with it. Maybe for
    somniluminescence or cold fusion! :)

    --
    sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  16. Yianni

    Yianni Guest



    The higher the frequency the less cleaning power. But... in higher
    frequencies, the cleaning power it reaches to smaller cavities, etc (for
    parts with holes, etc). I want to do a test for specific parts.
     
  17. Franc Zabkar

    Franc Zabkar Guest

    I don't know if this will be relevant to a 40kHz transducer being
    driven at 60kHz (if that's possible), but the 59kHz transducer in the
    following product range has a rated power of 25W whereas the 40kHz
    transducer with the same impedance is rated for 40W.

    http://www.annon-piezo.com/product/PZT-Transducer-cleaner.htm

    BTW, on closer examination of the circuit, it appears to me that the
    LM555 is switching a relay which in turn switches rectified but
    unfiltered mains voltage to the oscillator. I suspect that the piezo
    element determines the frequency of oscillation, and this oscillation
    appears to be amplitude modulated by the 120Hz/100Hz mains.

    - Franc Zabkar
     
  18. Yianni

    Yianni Guest

    Thank you for your time.

    I don't know, I suspect not because is an inexpensive chinese model.

    I took a look on them. It seems that none resembles the design of mine
    ultrasonic.

    The transducer is not as these you referred to the other post. These
    transducers are the "professional" transducers. This in the specific
    ultrasonic cleaner is more like a buzzer than a conventional transducer.
    It's diametre is twice than a conventional buzzer. Of course there is a
    small possibility to resonate to a specific frequency, but I think not. The
    reason for that, is that another model has just a NORMAL buzzer same as this
    for beeps. Of course both ultrasonic cleaners -I mentioned- are inexpensive
    chinese models with low power. A "normal" ultrasonic cleaner I have had, in
    15 seconds it cleaned the same as these cheap cleaners in 5 minutes.

    This is the "big" buzzer http://www.inkline.gr/temp/Photo 021.jpg . Epoxy
    glue (black) is used to fit on the metal tank. The glue and the metal tank
    should decrease much the resonate frequency. (Another fact for possible not
    resonance).
    The green area is not the oscillator
    http://www.inkline.gr/temp/Photo 019.jpg .
     
  19. Yianni

    Yianni Guest

    BTW, on closer examination of the circuit, it appears to me that the
    Yes, the 555 is switching the relay (on/off).

    I don't know what exactly this design is, but it seems you are right. The
    transformer has three pins. Two of them drive the transducer, and the other
    one is connected to the mains power. Parallel to the driving coil there is a
    capacitor.
    In the first I thought a simpler design. Now, I think the schematic is
    needed.
     
  20. Franc Zabkar

    Franc Zabkar Guest

    This URL claims that the design is patented, hence my question:
    http://www.codyson.net/cd-2800.html

    There is sometimes a patent number on the rating sticker.
    The power spec for your cleaner is 35W @ 110V and 50W @ 220V. That
    How about these "buzzer" shaped transducers:
    http://www.annon-piezo.com/product/PZT-ultrasonic-cleaner.htm

    They all have a well defined resonant frequency.
    I also wondered about that. I don't have an answer, though.
    Yes I am aware of that.

    - Franc Zabkar
     
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