My son yanked on the sustain pedal cable and broke some of the solder pads on the Back Panel Board - Assembly 121080. I am an Electrical Engineer in the pro-audio business and have serviced and repaired all types of audio equipment for many years. So I removed the sub-assembly and touched up the solder pads for the connector.
It was quite a bit later that I got around to re-installing the board. I connected J301, J302, J603 and J602. J602 goes to the power switch and J603 looks like it sends high voltage into the main unit - probably to the power amplifiers among other places. I plugged in the Molex connector to J603, oriented to the left (as looking down from the top of the component side of the board with the finished side of the connector plate facing you). This puts the Molex on the first 4 pins of J603 labeled "120V" as opposed to "240 volts" at the other end. J63 has a total of 7 pins - I plugged the mating Molex into pins 1 thru 4.
I plugged in the power cord and turned on the power switch - there was an immediate big flash ! I immediately removed power and inspected the board. The heavy trace from the 110v hot pin of the IEC power connector to pin 1 of J602 is burned off the board. Also, there are several ground traces - ground to pin 1 of J309 (battery assembly), pin 1 of J301 (engine), ground side of C4, trace from JMPR 9 to JMPR 5, and JMPR 5 to pin 4 of U1.
Obviously, I got something wrong and a large amount of current flowed through the ground plane. I have no idea if additional damage was done to electronics inside the piano. I am hoping the traces blew before anything else was damaged. Fuses F1 and F2 did not blow. Note that nothing happened when the power cord was plugged in - the damage happened only after the power switch was turned on.
So I am in need of some assistance ! The board is marked Assembly 121080, FAB 331080, REVD. I searched the Kurzweil web site for a home instruments service center in Orlando, Florida but none were listed. What I am requesting is :
1 - A service center in the Orlando Florida area that can come to my home and replace the Assembly, and check for additional damage.
2 - A service manual that shows schematic detail of Assembly 121080 and the proper connection of J602 and J603. As far as I can tell, I connected them in the correct order and polarity, but obviously I did not. Perhaps J603 needs to be offset on the row of 7 pins on the board ? J602 is for the power switch. The Molex harness has the same quantity of contacts as the mating PC board connector (4) and is keyed for polarity so I don't think that's the one I messed up.
3 - Price and availability of a replacement Assembly 121080. I can rebuild the damaged traces but I suspect there may be component damage.
4 - To speak to or correspond with a service technician who can review precisely what happened, and tell me what I plugged in wrong. I don't want to repair this board or order a new one and plug it in the same way again !! Also, a best guess on whether additional damage was done to electronics inside the main unit.
PLEASE HELP !!
Thanks !
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