Hi, We were recently given an old roland kr4500 but it has a right speaker sound problem; It is highly saturated and has to be deactivated otherwise piano is unusable. I changed ALL electrolyte capacitors from both main board and power supply board--> same issue . Also changed the stk4142 stereo amp and no change. I'm still waiting to receive 2 other IC C4570HA that reside on power board but have the feeling it won't change either. NOTE that in demo mode , speaker is working perfectly , saturation comes only when I generate sound from keys.Also , when headphones are plugged in, the right output is still saturated. I will look at buying an oscilloscope to run some further tests but any advise would be welcome. Other issues with the piano : -The pitch is not working but I will replace the potentiometer ( already had to change the volume for same reason.) The boards are in good condition, no obvious problem found but anyway have been cleaned up.The keys have been unmounted and cleaned OK.
SOURCE: My Roland Rd-500 has no sound....the factory demo
You either did not get the ribbon cable seated OR got it upside down.
If this cable is the flat ribbon with exposed solder plated points of contact, OFTEN those connectors have a latch to release by GENTLY moving tabs on eaither side in the direction of pulling the cable out. This lock MUST be moved out slightly to allow the cable to seat properly. The solder plated contacts will be FULLY into the connector when seated properly.
These cables ALSO can be inserted backwards and NO connection will be made.
Sounds like a blown motherboard to me. It needs to go to the shop.
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