Powers on shows a display and lets you set a duration. When I press Start I can hear a relay click and the timer counts down but it never really starts. Not sure if it's fixable or worth it but figured I'd post. Maybe someone has experience with these.
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Cheap ultrasonic cleaner doesn’t work anymore
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Re: Cheap ultrasonic cleaner doesn't work anymore
Originally posted by R_J View PostPull the board and look at the other side, there is likely an outout transistor that could be bad, or mybe just a poor connection.
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Re: Cheap ultrasonic cleaner doesn't work anymore
The output should be high frequency ac (42khz). Also Have a look at the piezo transducer (mounted to bowl) and see if it is cracked or broken
It is a switching power supply, U1 likely drives the two fets that drive the transformer, and the secondary of the transformer drives the piezoLast edited by R_J; 03-04-2020, 05:22 PM.
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Re: Cheap ultrasonic cleaner doesn't work anymore
Check the voltage across C10, it should be at least 150vdc), then use C10 - as ground and check the voltage on the 10k/2w resistor lead (next to C12). If you have voltage on C10 and not the resistor next to C12, check the solder connections on the relay, or the relay contacts could be bad.
Do you have VCC on the ic? or across C14?Last edited by R_J; 03-05-2020, 06:22 PM.
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Re: Cheap ultrasonic cleaner doesn't work anymore
Originally posted by R_J View PostCheck the voltage across C10, it should be at least 150vdc), then use C10 - as ground and check the voltage on the 10k/2w resistor lead (next to C12). If you have voltage on C10 and not the resistor next to C12, check the solder connections on the relay, or the relay contacts could be bad.
Do you have VCC on the ic? or across C14?
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Re: Cheap ultrasonic cleaner doesn't work anymore
Originally posted by R_J View PostCheck the voltage across C10, it should be at least 150vdc), then use C10 - as ground and check the voltage on the 10k/2w resistor lead (next to C12). If you have voltage on C10 and not the resistor next to C12, check the solder connections on the relay, or the relay contacts could be bad.
Do you have VCC on the ic? or across C14?
Same readings on R3 next to c12
C14 and Vcc of u1 = 13vdc when “start” pressed
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Re: Cheap ultrasonic cleaner doesn't work anymore
That all seems correct, you have 316v for the the fets, and 13vdc VCC for the ic, You could check the voltage between U1 pin 4 (common) and 5 (VS) should be quite high around 150vdc. If its 0 or 316v the ic could be bad.
Then I would check that the transformer is not open. I took a guess as to how it should be configured.(see picture)
The actual output circuit is very simple, U1 has High and low outputs to drive the two fets at 42khz, the two fets switch the 316vdc to output a 42khz signal to the piezo. The transformer provides a small sample of that signal to the CT pin of the U1 If that signal is missing the IC wil shut down.
If you have the ic's datasheet, you will see 4 internal fets, you should be able to check that they are not shorted D~S
IE: from pin 7 to pin 6 and pin 7 to pin 8 should be open.Last edited by R_J; 03-06-2020, 10:05 AM.
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Re: Cheap ultrasonic cleaner doesn't work anymore
It looks like the transformer is just there to provide feedback to the ic. If you have a scope (and isolation xfmr) to check the ic outputs, the circuit is very simple so if the fets are ok, the transformer seems ok, you have the voltages, HV for the output fets and VCC for the ic, maybe check that C16 (across the output to the piezo) is not shorted, it does'nt leave much.
I would try a new icLast edited by R_J; 03-07-2020, 10:31 AM.
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Re: Cheap ultrasonic cleaner doesn't work anymore
Originally posted by R_J View PostIt looks like the transformer is just there to provide feedback to the ic. If you have a scope (and isolation xfmr) to check the ic outputs, the circuit is very simple so if the fets are ok, the transformer seems ok, you have the voltages, HV for the output fets and VCC for the ic, I would try a new icLast edited by caphair; 03-07-2020, 10:32 AM.
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Re: Cheap ultrasonic cleaner doesn't work anymore
Originally posted by caphair View PostThe transformer isn’t stepping up the voltages at all? I don’t have a scope unfortunately. Should I just try another ic? This one is labeled IR2153 and I found replacements but it’s labeled IR2153S. Think it’ll be a suitable replacement?
The IR2153S is just an improved version of the icLast edited by R_J; 03-07-2020, 11:52 AM.
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