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Ultrasonic blows its fuse


#1

Hi folks,

Are there any ultrasonics experts in the orchidean panoply? My unit,
old and well used (perhaps “ill-used” might be more fitting) is most
often called upon to clean the dirt from mineral specimens. On several
occasions in the past I’ve left the unit running overnight without any
apparent ill effect.

Then, after some weeks of not being used, when I turned it on it blew
its fuse. I put in a new fuse: same result. That led to a visit to the
local corner electronics guy. He diagnosed a shorted-out “regulator
transistor” and put in a new one - a somewhat costly repair. Back at
home again it worked for about an hour and then once more blew the
fuse. And so back to the electronics guy. The transistor was still in
order, so he put in a slower acting fuse. This seems to have protected
the fuse at the expense of the component, for after a renewed hour of
use there was no more agitation of the water in the tank, although the
fuse was still intact. And again back to electronics guy, who said
that indeed it was the transistor that had blown again. Everything
else, he said, seemed to be in order.

The obvious question is, what might cause this transistor to
consistently short out? Do older ultrasonic units do this as a matter
of course? Do the stainless steel tanks perhaps develop invisible
leaks with age, dripping water onto the electronic circuitry?

Any informed speculations or long distance diagnoses will be greatly
welcomed.

Cheers & thanks Hans Durstling Moncton, Canada


#2

Howdy. As a matter of fact tanks can develop microscopic cracks that
leak water only when the ultrasonic is running and it can definitely
short out the board. Age and misuse is generally the cause of metal
fatigue under and around the transducer or the drain tube. We see this
from time to time and it causes a lot of grey hair here too as we
repair ultrasonics for a living. Is your unit just gone to the big tank
in the sky? Pretty hard to tell via e-mail, however it sounds like a
cracked transducer shorted out from the bottom due to leaks from the
tank. that will blow transistors and other components along with
diodes and resistors when no other visible damage is noted. If you are
not emotionally attached to the machine, make a planter out of it and
check with us for a nice rebuilt unit. (nasty self promotion
unashamedly offered) :slight_smile:

Mike Fritz & Dale Deviney
Lone Star Technical Services
The ultrasonic repair guys
If you don’t need us tiday, we’ll be here tomorrow.
www.ultrasonicrepair.com


#3

Hi Hans, First of all your corner electronic guy wouldn’t know much
about ultrasonics. It’s one thing to test components without power to
them. Electronic components can test good without power to the
circuit but may in fact be bad when the power is on.

Depending on the make of the sonic it may have one or more
transistors. If it has more than one usually if one is bad they all
need to be replaced. In addition some makes have other parts that
need to be replaced. This needs to be done because the parts may be
bad(leak) or they were not adequate to begin with. So a new different
part would be needed. Also other additional parts may be needed to
get the unit in proper working order.

All transducers loose capacitance over time and depending on how old
your unit is it may need the circuit adjusted so the action is at the
proper level.

All of these things are beyond the scope of knowledge a corner
electronics guy would know. Because ultrasonics are more of a
specialty type of electronic machine. It’s like comparing a general
practioner in medicine to a brain surgeon.

I’m sure he charged a pretty penny for the repair and hopefully he
gave you your money back when he failed to properly repair the unit.

Next, your question about tanks developing holes. Yes they do develop
pin holes. Once the holes have developed the tank will need to be
replaced. This is usually the most costly repair on a sonic. This is
so because the tank, transducers and heater all need to be replaced.
None of these parts are salvageable.

It also sounds to me like the electronics guy didn’t test his work.
If he had he would have found he couldn’t make the unit run for long
and never would have charged you to begin with. A good repair shop
will test the equipment.

We will NOT send a repaired ultrasonic out without ONE full day of
testing. This includes running the unit for about 3-5 hours shutting
it off and allowing it to cool completely then running it for another
3-5 hours. If it works like it is suppose to we will send it back and
if not we keep it and work on it more to get the unit right.

So no matter how desperate a customer is for the unit if they want a
guarantee on our work they have to wait this amount of time. If for
some reason we have an unusual problem and are having a hard time
finding it we offer to send a unit they can use in the mean time.

Because we have so much experience repairing equipment we don’t
usually have many problems getting the units back quickly. However,
an intermittent connection can cause us to be slow in repairing the
unit. An intermittent problem is always the hardest to find and fix.

If you don’t have a repair center that fixes ultrasonics regularly in
Canada you can send it to us and we will give you a free estimate and
we guarantee our work. So if you did have a problem with the unit
after the repair and in the warranty period we would pay to have the
unit brought back to us and fix it at no charge.

If you have any more questions please don’t hesitate to contact us.

We are MPG Repair; 407 south 5th St.; Livingston, MT 59047. Email is
@Ken_Kotoski1

Ken Kotoski
MPG Repair
Members of MJSA and Polygon.
Polygon ID 83941
Authorized Ney Repair Center.
We Repair The Tools Jewelers Use! TM
Copyright MPG Repair 2001


#4

It sound like the transducer that causes the take to oscillate is
causing a over current condition. All those years of use sometimes
cause internal bonded parts to dry out and delaminate ever so
slightly. When this happens the current draw may go up and cause a fuse
to go or other parts to give up their lunch! You just might have to
E-bay it and get a newer unit. Good Luck, but I still think the
"engine" that causes the unit to vibrate/oscillate is going or has
gone.

John Markowski III
Jemcubed Designs LLC.
www.jemcubed.com