SOURCE: my roland kc-60 has a
Does the hum exist with no cable plugged in? If so, take in for service. If there is no hum with cable out, then try new cable and/or musical instrument be it guitar or keyboard as the problem is likely in those.
SOURCE: i have a roland kc 150 65w amp that begins humming
First thing is to determine if sound is from the speaker or possibly the cabinet. If from the cabinet it is likely the power transformer is vibrating the chassis. This sometimes can be cured by adjusting the mounting bolts.
If the sound is from the speaker, then an electronic "cure" is needed. Please note that a very quiet hum is normal but if you can hear it 5 foot away, that is un-normal.
The hum would probably be due to failing component in the power supply. Unles you are adept at electronic repair, best to take it in for servicing.
SOURCE: My Roland kc 550 will not power on.
Hello,
if it does not power up, then it means its having a power problem. it might have worked fine in the past, but that's electronics for you. Power surge, irregular power supply, excess power supply, etc can affect the unit thereby not making it to power on.
This unit must have a power supply board in it where power enters from the mains. A capacitor, fuse, diode, etc may have been defective on the power board and maybe that's why its not making the unit turn on. There might also be some disconnection or something, inside the unit which is not making it to power on.
To actually find out what's wrong, you need to disassemble the unit with a screw driver and check what's wrong. You will be needing a meter in order to test the components on the power board, once you detect any bad component, you can make necessary replacement at any electronics accessories store withing our vicinity. This is the only way by which you can detect the problem.
Of course, testing the power board with a meter will require someone that has the ability. So it you can't, then you might be needing the help of a repairman or you can call a friend that has the ability to help you out.
I wish you the best of luck.
Take care........
Sounds like you have a poor or open ground if the loud noise is 50 or 60 Hertz. If you have the loud noise when the keyboard not connected then the open ground is in the amp. Often times it is only a cold or bad solder connection which you can touch up with a solder iron and some rosin core solder. If the noise disappears when the keyboard is not connected then I would look at the patch cord first and the connectors second. If you have a second amp you can test to cord and keyboard to verify the problem is the keyboard. If you have to touch up the solder connections, unplug and open up the unit. Make sure all connectors or seated and none of them are loose. Use a grounded three prong solder iron and 60/40 rosin core solder. Heat up connections on the connector and add a small bit of solder to each connection. Next heat up the solder connections on the circuit board and quickly add some solder. Caution, do not apply to much heat on the circuit board or the copper trace will lift off the board so you need to use as little heat as possible just to start the solder to flow then let it cool.
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