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cheap ultrasonic cleaner

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Seabeowner:
Ash, took that onboard. It was marked as "Quality Guaranteed, CE / FCC / ROHS" with copies of certifications on their site. (genuine??) China made, but distributed from UK. They asked me to inspect the main board for them before I finally returned it and it actually looked very neat and good quality.

AshimotoK0:

--- Quote from: Seabeowner on November 06, 2016, 04:57:41 PM ---Ash, took that onboard. It was marked as "Quality Guaranteed, CE / FCC / ROHS" with copies of certifications on their site. (genuine??) China made, but distributed from UK. They asked me to inspect the main board for them before I finally returned it and it actually looked very neat and good quality.

--- End quote ---

OK sounds good then . TBH the transistors/IGBT's etc that drive the ultrasonic transducers lead a hard life switching a capacitive load at high powers/frequencies and even the UK made ones have a tendency to go 'pop'. Plus manufacturers are now building in obsolescence by integrating the drive electronics within the microcontroller. If the microcontroller goes defective it's pre-programmed and they won't give you the code to reprogramme a new one or even sell a pre-programmed one. So BEWARE paying a lot for a modern 'Ultrawave' one or other 'high end' types.

K2-K6:
I've nothing like the electronics knowledge of Ash but along a similar vein of low cost manufactures of machinery I've recently worked on a Chinese made chainsaw for somebody.

Speaking to somebody who runs a garden machine repair company, they told me that they won't even offer to work on machines manufactured like this.
So had a good look at it as it was stubbornly a non runner and at first appearance it looks OK and quite well designed. This is really the core of the problem as the design is a straight rip off of a genuine Stihl machine, so they had nothing to do with this part of the process. Even the plastics used are made to mimic the colour and layout of the Stihl.

Getting further into it,  the original problem seems to have been the flywheel had never been properly tightened so that during initial use it had been running loose on its taper and rattled the woodruff key almost to nothing. Had to tap (panel beat, peen) the keyway back into shape or the crank was scrap. The jet circuits it the carb had blocked as it hadn't been used recently, so cleaned it all out and set it up to its manual which stated a start point for the idle jet was one and a quarter turns out but would not start. Eventually get to about one eighth of a turn to get it going but any linearity of the screw is absolutely minute with almost breathing on it to give you a run or stop setting. Looks like the taper on the needle valve and seat are just too course to give any sensible response.

The upshot of it is that it does go and work as a chainsaw but looks more impressive than it functions.

In addition, the plastic casings are clamped by torx screws that you can't really tighten as no ferrules are fitted to prevent the plastic being squashed even on high load casings like the pull start / recoil unit. The metal on important fixings is only just sufficient to withstand the load required to keep parts in place and the clutch drive for the chain is made with such a poor tolerance (if at all having any checks applied during manufacture) that it will not run concentrically, making the chain tension vary wildly.

The instructions claim compliance with euro laws etc and I know the price point is very different from quality brands but really its not going to function for long as a chainsaw from what I can see.
Bit of a rant really but I think it illustrates for me how nicking a good design from someone who has spent the cash on R&D and long term testing, then produced it with substandard materials and methods can end up with something not really fit for purpose, however it's dressed up.

Rozabikes Tim:
Think I just bougt the same model of chainsaw. First pull, the cord return mechanism packed in!! Now sorted and does what a chainsaw does but just fear its a handgrenade waiting to explode. Knew i was buying cheap but just thought as it wouldn't get much use, it would be ok.

When you look at the piss poor design of the cord recoil, you think - what more cost would it be to design it properly from the outset? Such a simple function that's been about for years.

You pays your money etc...

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