|Colin Heseltine||16/03/2020 20:06:21|
|607 forum posts|
Added these comments to another thread but seen no responses so moved by problem to its own thread.
My Ultrasonic cleaner has died. It powers on okay, heats up okay, appears to start on the timer and switches off again after appropriate time but I do not get the ZiZiZi noise it used to emit. No bubbles or cleaning.
Taken the bottom of to check for problems and can see no issues. Checked all 6 fuses are okay, can see no melted or blown bits, all wires connected and good. It is model with 4 transducers.
See picture below of board.
Does anyone have any ideas of where or what I can test.
1094 forum posts
Colin, the short answer is no I don't -- wish I did because I have one with the same problem but electricity / electronics are not my forte. I did ask a pal who is pretty good on this stuff but he drew a blank, my guess and it is a guess its the transducer[s] or probably what drives them ???
Hope fully someone with the necessary knowledge will be along and I will watch the thread with interest
|I.M. OUTAHERE||16/03/2020 22:47:45|
|1468 forum posts|
My first port of call would be the two relays on the right hand board , it is possible that these control the power to the heater and circuit for the transducers and would be switched via the timer and start switch on the front panel .
Please don’t go poking around in there with the power connected - ☠️
|34 forum posts|
Further to -:
It may not be the relay themselves I've known relays to give problems at their soldered pins, two scenarios here, one bad soldering and the relay causing 'shock waves' loosening the soldering around the pins.
As pointed out be very careful, it's not the main potential but the charge on the capacitors - switch-mode power supplies, aka. 'switchers', rectifies the mains to dc, so we have 240 x 1.42 = 340V DC appx. on the smoothing capacitors - they can stay charges, short them out before touching WITH THE UNIT UNPLUGGED, I either use a 470 Ohm 1Watt resistor or a small 240V lamp bulb, out of a fridge say.
An inspection of the relays will do no harm.... but there are time when you need a test meter and times when it needs to be powered up with the PCB accessible from underneath.
Its the volt that jolts and the mills that kill.... a mill is 0.001 of an amp - you only need a couple or so across 'ticker'
303 forum posts
on the industrial ones I work on its usually the frequency generator that fails, as you say everything else appears to be working - however on domestic ones I have no idea what or where the generator would be located
|not done it yet||19/03/2020 16:45:15|
|6284 forum posts|
In addition to Sparks’ warning, only poke around one handed. Keep the other hand in your pocket. DC would give you a rather nasty jolt but hopefully not along one arm, across your chest and to earth through the other arm. So less likely to stop your ticker.
A continuous DC shock often causes whatever one might be holding to ‘stick in your grip’ because the muscles will contract, thus not letting you release the grip.
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