I need a power transformer for roland sde -3000

Is the transformer you are using the original? or are you using one that you picked up. If it is not the original, you have to make sure that the voltage and ground on the plug matches what the unit needs. Some adapters reverse the + and - on the tip and sleeve on the plug.

I see that´s a pretty expensive power supply.

option 1: buy an equivalent power supply and adapt the cord.
IN: AC 120V 60Hz 12W
OUT: DC +10 V 500mA
DC -10 V 150mA

option 2: Build a new power supply by a kit
something like this:
http://electronics-lab.com/projects/power/011/DUAL%20VOLTAGE%20POWER%20SUPPLY.JPG

Change the 7812 and 7912 by 7810 and 7910. you will get the 10V needed.

option 3: you can try to repair the power supply. check if there is no broken wires or a blown thermal fuse in the transformer.

Are you using the correct AC adapter? An aftermarket unit will do this if the power is insufficient, or the polarity is wrong (- / +). If you're using an aftermarket unit, it may not be providing the right amount of Amps and Voltage to the unit; causing the display to blink. You can try this cord to help: http://www.powerpayless.com/ac-power-adapter-for-roland-r-8-r8-drum-machine.html

The internals run on +/-15 Volts and +5 volts. While schematics show the audio and digital circuits they fail to show the power supply. I suspect the supply uses regulators such as the 7815 family so one would want around 18 to 20 volts DC of each polarity.A transformer would likely be about a 28 to 30 VAC centertapped. HOWEVER transformers rarely fail. There should be fuses to protect the transformer. Some Behringer equipment uses a switching supply. Common failures in those is the switching transistor. When testing these units, it is useful to place a 25 watt incandescent lamp in series with the power cord to save fuses and act as a resetable fuse that will send a limited current into the unit for testing.

Here's a link to the Owner's Manual
for a service manual, you're probably going to have to contact Roland directly, since they don't even list the fp-8 on their website. Service manuals for their other products only run about five bucks for a hard copy, i believe. I'm sure you can get to the right place through here: http://www.rolandus.com/corporate/contact_us/

If you are on 220 there, just get a 220 to 110 TRANSFORMER type step down. You don't need a very big one, then you can use the supplied convertor. DO NOT use one that is intended for hair dryers type appliances.

The only simple way that I could think of is for you to purchase a STEP DOWN TRANSFORMER rated at 500 watt, 110 volts, 60cycle. The transformer inside that amplifier have four output 12v and 15v DC.2amps It will be hard to get the transformer for that! Hope that might help you! taah!

Unit has wide range power supply will operate on 100 volts to 240 volts without any change other than possible plug adapter to mate with each countries receptacle standard.

There is a jumper (JP1 or J1). If you cut that jumper, the mixer will operate for 220V. This power supply is the same with the ones used in desktop computers. I did that to my mixer bought from US made for 110v. I replaced that jumper with a switch (from a desktop power supply), I made a whole and I fixed the switch on the pack panel of the mixer. So now, I can switch it manually for 110v or 220v. It's working perfectly. I tested it for long time and no problems. Good luck.
PS. I called the Behringer technical support in the US and they weren't able to teach me that. So I figured it out myself after a big research. See the pictures about my project. :)

Ok guys. Just got mine XP50 fixed with the "No Display" problem. The LCD screen was blank without text and only shown orange color. The problem is one of the capacitors on the main board was dead. I have replaced all 3 caps on the main board and the problem is solved and if you are a little handy on soldering, you can do it yourself. The 3 caps you should replace are:

- C901 (I used 16V 330MicroF)
- C65 (I used 5V 4.7 MicroF)
- C 902 (I used 16V 330 MicroF)