Casio CTK 800 spare key

Question moved from Cars and Trucks to a Casio Keyboard one.
Easy enough if you can find the part.

https://www.google.com/search?q=casio+wk-1250+parts+diagram

casio WK1250 Parts and Accessories - PacParts

https://www.pacparts.com > model > model_id=WK1250
Mfg / Model No, Description, PDF, Year. casio WK1250, Musical Instrument: Electronic Keyboard, 1998. The following parts are available for the model listed ...

Casio WK-1250 Repair Parts and Accessories - Syntaur

https://syntaur.com > keyboard > keyboard=2080
Casio WK-1250. Released in 1998. The WK-1250 is a 73-note consumer keyboard with built-in speakers. Synth. All photos are copyrighted by Syntaur, ...

Casio Keyboard Junkyard: Welcome

https://casiokeyboardjunkyard.com Used accessories, parts and stuff for Casio Keyboards ... CASIO WK-1200, WK-1250, WK-1300, WK-1350 models are basically the same and use the same parts.

Casio Repair Parts - Keyboard Kountry

https://www.keyboardkountry.com > keyboard-parts
Casio Repair Parts ; Yamaha Brand Key Lube (Small). $3.80 ; Casio CTK-560L Ma1M Light Boards. $9.95 ; Replacement Keys for Casio CTK-491 and Others. $10.95.
Missing: 1250 ‎' Must include: 1250 ..

A Casio Keyboard Service Centre is the best idea.

Casio Ctk-900 Service Manual - CTK900 - HelpOwl.com

https://www.helpowl.com > Casio > CTK900 > Research
Casio Ctk-900 Service Manual - CTK900 ... Get support for Casio CTK900 ... Our system has returned the following pages from the Casio CTK900 data we have on ...

Manual Casio CTK-900 (page 1 of 108) (English) - Libble.eu

https://www.libble.eu > ... > Casio > CTK-900
View and download the Manual of Casio CTK-900 Keyboard (page 1 of 108) (English). ... authorized CASIO Service Provider. AC Adaptor

Question moved to Casio Keyboards.

Take it in for service. Sounds like it needs a new switch or control board.

https://www.google.com/search?q=Casio+CTK+4400

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CTK-573 is the closest.

https://www.manualslib.com/manual/268824/Casio-Ctk-573.html?page=10#manual

or Contact Casio Support as they skim past your model.

https://world.casio.com/manual/emi/

There is a 4 minute video here, as well as sales info

https://www.google.com/search?safe=off&rlz=1C1QJDB_enCA643CA644&sxsrf=ALeKk01dcFCTEp0bmZKf-_Hkm-coJ2n4zw%3A1611763599264&ei=j48RYPbRD8iEwbkPy_K0sAk&q=casio+ctk+574+61

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Is it broken to pieces or just came off.
I would open up try glue to pieces together and then swap the repaired key F4 with say the (less used) F6 key.

hi iam bying on casio key board modal no;cti 810in how playin tamil song witch no?witch retham?

When wiring around circuit board cracks, one must use adequate sized wires and keep the leads short. Also you MAY have a microscopic crack in yet another conductor that flexes when you play the keyboard and freezes it. Use a high intensity LED light from the topside to "candle" the board and look for cracks. Look for cracking of the board material that may have tiny cracks in the circuit traces.

First make sure a keyboard "split" option is not set.

Probably you are going to have to clean the key contacts. They are likely conductive rubber "pills" that are pressed onto a circuit board that has interleaved fingers. Clean both the black pills and the circuit board using ONLY 99% isoprophyl alcohol and Q-Tips.

There is a chance that the jack that the power supply plugs into is broken loose or has bad solder joints to the circuit board. I am hoping that you purchased a direct replacement for the power supply.

That doesn't sound good. It sounds as if the processor is locking up and that might only be fixed by replacing the main board. Sometimes this happens if a unit gets fried by static electricity.

But before giving up, I would open up the unit and check for loose cables and connectors internally. If there are chips (IC's) that are socketed on circuit boards, push them down firmly. Things may start working again.