I'm an electronic technician so I have a little experienece with power supplies, etc, but electronic keyboards is NOT my strong point. My A-33 appears to be destroying power supplies as soon as I plug them in. No smoke, smell etc, they just stop putting out 9V DC (center tap)when measured w/my meter. Any ideas, particular what resistance should I be seeing at Rolands' input with the A-33's power switch on and off. No power supply plugged in during measurements, of course. Thanks! Tom Adams

If your Yamaha PSR-2000 keyboard is turning on and the blue backlight is displayed on the screen, but none of the function keys are lit up and not responding, there may be a few different causes.

1. Check if the power supply is working properly and is providing enough power to the keyboard. If the power supply is faulty, it may not be providing enough power to the keyboard.
2. Make sure that the keyboard's internal battery is charged. If the battery is low, the keyboard may not function properly.
3. Check if the internal fuse of the keyboard is not blown, which is a common problem on electronic devices.
4. If none of the above steps work, the problem may be with the control board or the display, and the machine may need to be serviced by a professional technician.

I would recommend checking the user manual or contacting the Yamaha technical support for further assistance, as they may have specific troubleshooting steps or solutions for your model.

You can repair any keyboard problems by taking it apart. Find the plastic mats with the exposed electrical contacts and look for food dirt, sugar syrups etc. Using a little water and a toothbrush clean and rinse the food covered areas and pat dry. Leave it to dry for an hour. Try putting it back together and see if it works. If not.... then take the offending letters and look for where the carbon paint touches those contacts and either repaint with carbon paint (available from a quality electronic supply) or just use crazy glue gel and glue little foil pieces to each carbon painted spot that is acting up. This works for remote controls too.

Voltages sometime increase/decrease during power outages. This mainly afftects the power supply of a lot of electronics equipment.
1. Check the fuse.
2. Check primary components like; Bridge rectifier, filter cap, switching components etc.
3. Check secondary (cold) side once you isolate the primary side to be ok.
Please consult a professional technician if you are not skilled in electronics repairing.

All the best
Rjn

Hello
There is somethin wrong with either its EHT section or power supply section. Your description gives me very little to say a strong opinion. In both cases, it is very dangerous to handle the components at these sections. If you haven't got enough experience in handling high voltage electronic sections, never attempt to do anything with this TV. Normally EHT arcing is more common to this type RCA sets. In my opinion, get it repaired by any experienced service technician. OK.

Power cord is not the the faulty parts alone why your unit didn't power on.
It is quite technical if youre not a technician. It is most likely you have a faulty power supply.
I've advice you to send it to repair shop or look for a qualified technician to check the low voltage power supply (regulator I.C., H-out transistor fusible resistor,dry joints,etc...).

But first check the warranty of your unit if it is already void.If not avail it, the manufacturer will fix it for free and/or little charge only...

Please rate my help,

Thanks for using fixya...

This could be ay number of things, but assuming that the power supply is fine (the cord isn't broken on either end or down the length of the cord) then it'll probably be a loose connection in the keyboard.
With CTK models if you unscrew the back (not the metal plate) you can open it up, have a look where the connections are going from the power supply socket and re-solder to the board etc if nessesary. Also if you have some strong glue then glueing the adapter in place on the PCB as well as the headphone socket would be a good idea as these connections are used quite a lot and the parts do come loose.

It is either the backlight inverter is not getting the 24vdc from the power supply or the inverter board is bad. Look for bad components, short circuits, dark brown heat spots, fuses.
If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

http://s807.photobucket.com/home/budm/allalbums

http://en.wikipedia.org/wiki/Capacitor_plague

Parts: www.shopjimmy.com

mother board has fried. jump on ebay to find another board and replace it.

Considering you are an electronics technician, you will know this is a loaded question. Your best bet is to swap the power supply with another one (if you have access to another pc) Most modern PC power supplies are the same now, although as they go back in age, there are some differences.. Anyway, best to swap power supplies with a known good one and see if the symptoms change. If it works, then yes, faultfind the power supply.

As you will know, it will be a switched mode supply, therefore dangerous to test in open circuit state.. Be carefull! - As a technician, you will know that you can check some obvious test points, for example the diode bridge and somewhere near the output, where you might expect correct DV volts. A 'CRO' might be handy here as well, but a digital Volt/Ohm meter is OK too.

Try these sites for help:

http://www.daileyint.com/hmdpc/manual.htm

http://www.repairfaq.org/sam/smpsfaq.htm

Remember: Beware of dangerous voltages in switched mode power supplies. They can bite! It may be better to replace the unit.

There are a number of issues that could cause this, the most likely culprit is the power supply, when I say power supply I mean the internal power supply, 
This means that you have already obtained a good "known to work" AC to DC power supply, and tested it on your keyboard to see if that is the problem. 
If you have completed this step, then your next step is to test your unit with batteries only, if the keyboard works, then you know your problem, is internal to the keyboard. 
There are two issues to check, before proceeding please read the following note.
 (a note here for those who have no experience working with internal electronics)
If you have no experience working with internal electronics I would not recommend, opening your keyboard. 
Two reasons, one, will void warranty if it still is under warranty. 
secondly, you could accidently cause more damage to the unit. 
Now if you are still reading, and feeling confident, you know that as a child you have dissembled many many electronic devices, just to see how they work. 
If you do decide to open the box, disconnect the power supply to the unit including any batteries. 
open the box and locate the power on button, clean using a Dielectric cleaning agent, can be obtained at most electronic specialty stores. 
clean the power button, may work but doubtful, usually the switch itself is usually bad, there is a way to test the switch, however, that is beyond the scope of this answer, if you are following this you will most likely have the knowledge to do this. 
The second and more challenging issue will be the internal power supply to the keyboard, or the interface that connects to your ac to dc converter. 
This can be much more trickier, and I wont go into it here. 
If you test your power switch determine that it is good then you should consider getting the unit serviced by a technician. 
If you examine the boards, (electronic circuit boards,) and notice burned, connections, (darker than other circuits) then most likely it will not be worth trying to fix. 
Hope this helps somewhat, if nothing else, take this print out to your local service dealer, and that will help in getting your keyboard repaired, 
Delete this part, before taking this to your dealer, 
Most electronic products can be easily fixed with a power switch, or power supply, however, many dealers will not tell you this and give you an estimate of fixing the unit that far exceeds the actual cost of repair, 
an example, in a local TV repair shop, a friend brought in a wide screen Plasma HD TV, quoted repair, $654.00  problem, 
power supply, actual cost, $75.00 my friend ordered the part online and with the help of a friend installed the new power supply returning his unit to full functionality. 
So beware,