Amazon.com: Digipartspower AC Adapter Charger for Casio Piano Keyboard CTK-500 CTK-501 MA-170 Power : Electronics
Casio Ctk-501 Grey | Reverb
K-MAINS AC Adapter Charger Replacement for Casio CTK-500 CTK-501 CTK-540 CTK-450 Power Cord Charger - Walmart.com
Casio CTK-501 Repair - iFixit
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Amazon.com: MaxLLTo 9V Power Supply Cord Charger, 6 FT Extra Long Replacement AC Adapter for Casio Keyboard CTK-500, CTK-501, CTK-510, CTK-511, CTK-515, CTK-518, CTK-519, CTK-520, CTK-520L, CTK-530 : Musical Instruments