Hi Folks,
Talk about diving in at the deep end... I'm the wrong sort of engineer (materials, and now IT sysadmin) so last time I did electronics was in 1st year circa 1988...
however, I have nothing to lose...
I have the following Ultrasonic cleaner purchased about a decade ago (~$425 from JayCar)
https://www.jaycar.com.au/ultrasonic-cleaner-commercial/p/YH5410
it stopped working recently, so it got disassembled. looks like several of the resistors are kaput, but most of the rest of the components (capacitors, transformers etc look OK - no obvious burnout or damage).
Cause of the failure is probably overheating/overload because forced damped load with uncontrolled variable load (I put something too heavy in) or excess moisture (I spilled some water once too often).
I'm content to replace the broken bits and see how it goes... however... I'm having trouble identifying the capacity of the burned out resistors...
Photos - raw board.
I've had a go at working out the circuit...
The broken resistors are R3 and R13.
White IC is a switch (http://pdf1.alldatasheet.com/datasheet-pdf/view/5044/MOTOROLA/MOC3083.html)
R13 is part of the power conditioning circuit
R3 is part of the oscillator circuit. That's the one that is bugging me...
It's old and damaged and it's hard to read the colours, but I think it's orange black gold (gold) - making it 3 ohms.
that's low... mind you, R18 & R19 are 0.22 ohms
There is a second board that connects to the L & N connectors in the middle of the board that basically repeats the circuit. R3 on that one is also destroyed, as is R18 & R19.
So, before I go out and buy some replacement parts, do those numbers - 0.22 ohms and 3 ohms - make sense? DO I believe my guess work?
Talk about diving in at the deep end... I'm the wrong sort of engineer (materials, and now IT sysadmin) so last time I did electronics was in 1st year circa 1988...
however, I have nothing to lose...
I have the following Ultrasonic cleaner purchased about a decade ago (~$425 from JayCar)
https://www.jaycar.com.au/ultrasonic-cleaner-commercial/p/YH5410
it stopped working recently, so it got disassembled. looks like several of the resistors are kaput, but most of the rest of the components (capacitors, transformers etc look OK - no obvious burnout or damage).
Cause of the failure is probably overheating/overload because forced damped load with uncontrolled variable load (I put something too heavy in) or excess moisture (I spilled some water once too often).
I'm content to replace the broken bits and see how it goes... however... I'm having trouble identifying the capacity of the burned out resistors...
Photos - raw board.
I've had a go at working out the circuit...
The broken resistors are R3 and R13.
White IC is a switch (http://pdf1.alldatasheet.com/datasheet-pdf/view/5044/MOTOROLA/MOC3083.html)
R13 is part of the power conditioning circuit
R3 is part of the oscillator circuit. That's the one that is bugging me...
It's old and damaged and it's hard to read the colours, but I think it's orange black gold (gold) - making it 3 ohms.
that's low... mind you, R18 & R19 are 0.22 ohms
There is a second board that connects to the L & N connectors in the middle of the board that basically repeats the circuit. R3 on that one is also destroyed, as is R18 & R19.
So, before I go out and buy some replacement parts, do those numbers - 0.22 ohms and 3 ohms - make sense? DO I believe my guess work?