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LK-230 Keyboard Power Issue

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Keyboard will not power-up/play with the AC adapter. The adapter voltage reads 9v. The voltage where the adapter jack is soldered to the printed circuit board also reads 9 volts verifying the jack is good. It will power-up/play with batteries. Any suggestions?

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When you measured the voltage where the adapter jack solders to the circuit board, did you measure with the keyboard powered on or off?.  If you measured with the keyboard powered off, all you did was make a no-load test of the power adapter.  If it is bad, its output voltage could be dropping drastically when it is placed under a load.  You need to make that measurement with the keyboard powered on and the adapter under full load, and no batteries in the battery compartment, so that you don't mistake battery voltage for adapter voltage.  I apologize if these things seem overly basic to you.  I am not trying to insult your intelligence or your experience.  It's just that these are all I can think of, at this point, that could give you the results you are getting

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Since it is a new recommended ac adapter, I never considered checking it's voltage under load. Thanks for the suggestion.  I'll take the key board cover off and check it. Looking ahead. If the voltage is good. Is the key board junk or repairable?

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When you remove the cover to make that measurement, make sure you pull any batteries first.  As you check the adapter's voltage, verify its polarity as well.  Accessories sometimes get mislabeled or put into the wrong boxes - which brings up a possbile problem.  There could be a blown fuse (or diode being used as a fuse) that is part of the adapter jack circuit.  It would have to be in the adapter's current path, but not in the battery's current path.  If the adapter checks out OK, this or a bad circuit board foil in the adapter's current path is most likely the problem.

 

As long as the board will run on batteries, I am not sure I would junk it.  At least, with batteries, you can get some use out of it, plus there is always the possibility of wiring the adapter's output directly to the battery compartment leads.  If you were to do this, you would never want to have batteries in the compartment with the adapter connected to a power source, or the batteries would most likely overheat and explode.  The adapter jack has a built-in switch that prevents this, but a direct wired connection would not.

 

The LK-230 was a nice board for its intended use, but it was a low priced board, so you would want to be very cautious of any repair costs, which could quickly be into the price range of a new board or a used board in good shape.

 

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The adapter input voltage with the power switch on measured 9 volts. So as you indicated something in the adapter circuit is bad. Oh well, less expensive AA batteries will have to be the best fix. Thanks for your help.

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Since it is a new recommended ac adapter, I never considered checking it's voltage under load. Thanks for the suggestion.  I'll take the key board cover off and check it. Looking ahead. If the voltage is good. Is the key board junk or repairable?

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