Repair needed - Cash reward for success

I have a small analog circuit board that we believe
has one or more defective components. If anyone
Locates and replaces the defective part, my boss
will pay the repair person $ 200 if his machine
works again !
He’ll pay for parts regardless.
My name is Tom, and i can be reached at

Here is where the board is stored
at maker space. Please return the board to
that location if you test it. And if you remove
the board from maker space please contact
me first :grinning:

Does Vector allow personal storage in their committee area?

What is it supposed to do, and what is it not doing now? What makes you think it’s broken, and what would working look like?


It’s an Alludium Q-36 explosive space modulator.


Or the origins of SkyNet. Better make sure theres no wifi on that thing

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out of a Mac??

I took a quick look at this module. I am not interested in trying to repair this circuit board. I am only posting this information in case someone else would like to take up this challenge for one of our fellow makers.

The Manufacturer’s name is Magtonic, a maker of exercise equipment. It look like a simple power supply that controls a DC motor. It requires 110 VAC on the input, has 2 output terminals labeled M- and M+, most likely for the external DC motor. Then there is also a small 3 pin connector, most likely for external controls. There is an empty fuse holder, no fuse. There is no noticeable component damage that I could see. It does not look like any repairs have been made, only some component glue was scratched off to see the part number of the circuit board, SR-8050. It is a single sided circuit board and a schematic could easily be traced out to assist with the repairs.

All of the IC and transistor numbers are clearly visible:

  1. LM339, Analog Comparator IC
  2. LM358, Analog OP Amp
  3. L0548(?), Opto-Coupler
  4. 7812, 12 Volt Regulator
  5. IRF640, Power FET on the heatsink
  6. Plus a variety of small transistors, diodes, etc.

The circuitry looks rather simple. OK folks, here is your initial technical information. Now it is up to someone else to take the reins and make a little quick cash.


I’m no expert, but that seems like a potential fault.


This is the board

Dibs on fixing the fuse for $200


Go ahead, that board blew all 5 we put in
there, maybe you put them in better, or
we put them in backwards ? Yeah. Maybe.

Thanks lot’s !!! You’re a real champ !!
I have limited posting ability.

well ESmith, we thought letting it blow a 6th one, was starting to feel ridiculous, how many fuses do you like to feed it before deciding there’s a bad component on the board ? We thought 6 was enuf but, maybe 7 was the charm ? Probably missed our chance…

Key information was withheld from initial description.


What size fuse was put in it? What does this board go to? What machine? What size motor does it power etc?

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I have a fuse we can try.

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But seriously has anyone checked the MOSFETs

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Does the maker space have one of those Multifunction Transistor Tester?

ELab has a Peak Design Ltd DCA75 semiconductor tester/curve tracer.
See tool wiki fro link to manual -

Going on memory here - think part to be tested has to be removed from ckt before testing.

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I am unable to see how that is relevant to
testing “in circuit” individual components.
Our view is that if all those components
are operating “within specs” the board will
return to doing what it used to do.

But, here you go…
it has three pins that receive input from a
“control board” that allows selection among
7 speeds ( most likely PWM…) and,
the selection of a "run time … although,
the timer circuit is on that control panel board.

The motor is a Y6TA9B, 90v DC, 7A,
3600 RPM… it is installed into a “Power
Vibe” model “Power Pro 20136” made in
Belgium 13 years ago. It’s use is to treat
failing lymph system in primarily those
who have problems with age, diabetes,
or obesity.

Fuse was 5a. But we prefer that no one
powers the board which may create
unnecessary risk since the most obvious
issue is repeated fuse failure. We feel the
fuse is protecting more fragile parts from
overload and continuing to repeat the
fuse-failure process could pass thru
enough spikes to damage the parts the
fuse is intended to protect …

I hope that answer was adequate :blush:


When does the fuse blow? immediately or when attempting to drive the device?