Anyone familiar with ultrasonic generators?

[soldersplatter]

Anyone familiar with ultrasonic generators? I'm hoping someone here knows which components typically fail inside the generator.

These 20kHz generators are rather basic Chinese units (see pictures) used for welding nonwoven plastic (basically thin plastic fabric). I have a good/working unit and a bad/failing unit so in theory I should be able to compare good versus bad components. Both sets of converters and horns are fine since the good generator can drive both sets.

Any constructive input is appreciated.

Also, if there's a better forum to ask this question please let me know


FYI - I'm no electronics expert: I have previously monkeyed with picBasic and 16f88 chips but that's about it.

 

[soldersplatter]

For future reference I will answer my own problem:

The problem was/is located on the board circled in green below. Swapping a board from a working generator allowed me to locate the problem. Board is essentially rows of transistors (C4237) and resistors. Now time to find the bad transistor.








- - - Updated - - -

For future reference I will answer my own problem:

The problem was/is located on the board circled in green below. Swapping a board from a working generator allowed me to locate the problem. Board is essentially rows of transistors (C4237) and resistors. Now time to find the bad transistor.

 

[woutnme]

HI sorry for delay, im ultrasonic manufacturer in spain, that u found broken its the half H bridge, if your machine have over current for come moments can occur it burn.
all chinense machines look like yours, are very home made, if in a futher u need some help dont henitate contact with me.
Bye
Good luck