Yamaha portable keyboard won't turn on

SOURCE: yamaha htr-5830

I own this receiver, and 18db is damn loud. Granted - your room might be significantly larger than mine with your speakers spread much further apart, or your speakers might be much less efficient than mine (this means that they want more power than the receiver can dish out - I have whatever speakers came with the "YAMAHA Home Theater in a Box" [the model that came with the HTR-5830]), but I'm pretty sure that the receiver doesn't get any louder (or at least not much). My suggestion is to turn down the volume to about -20db and work up from there after the movie has started. It might be easier to test the volume using music. The negative sign is deceiving - I rarely bring mine up to 0db. Also check the resistance - there's a red switch on the back of the receiver that switches between 6 and 8 ohms - make sure that it matches your speakers' resistance. If turning down the volume doesn't work, then post the problem again. Hope This Helps.

SOURCE: yamaha receiver model rx-v550

it is your protection circuit working, preventing the unit from any further damage to circuitry. you can check first your speaker cabling for any short connections, possibly red/black terminal wires got entangled. if all ok then try removing all speakers then turn on the amp. if still does the same thing turning off then you have a problem with the amp output stage, shorted power output transistrs/driver probably. if the unit turns on normal without the speakers then you must have one or both of your speakers busted. by the way this amp is multi channel, after removing ALL the speakers connected, and does not turn off anymore, put the speakers back one by one and observe if the unit with turn off and on which set of speakers. otherwise if still trips even without the speakers, it is your amplifier that is deffeective, any of the five channels, main, rear,center. let me know result so i can guide you on how you can get it repaired and what will be the extent of damage in case.

reden

SOURCE: Instruction manual for a Yamaha PSR 195 keyboard.

Try going to http://www.yamaha.co.jp/manual/english/index.php. There, you can try to find your owners manual for free.

SOURCE: Yamaha RX-V995 receiver turns on & then powers off 2 seconds late

I suggest you run self diag.  press [FM/AM] key + [Input mode] key and press the [power/standby] switch.

ps prt = power supply problem
dc prt = shorted output or leakly cap in channel
tmp prt means to hot on heatsink

you'll likely have to measure the resistances of the output FETs to find a short, 

SOURCE: Yamaha PSR-510 Keyboard

There is no need for a manual. It is so easy to operate because it is designed for easy opeating. If you need a manual to operate the PSR-510 then you really won't be able to operate it even after studying the manual. But here it is just in case you can by some miracle!
http://www2.yamaha.co.jp/manual/pdf/emi/english/port/PSR510E.pdf