New Rigol dho804 oscillocope

I use  the power adaptor provided in the accessories box and I connect it to the AC power source (220 V, 50 Hz ).

Definitely.
You can try to repair an used instrument which you bought on E-Bay for example.
I did this myself, last time it was an Agilent 53132A frequency counter which I bought from China. The instrument comes, but after power up, the panel was dead. I opened it and I found that the flat cable between panel and main board was unconnected. I reconnect the cable and the instrument started without any problem. But it was a used instrument, without the warranty.
In your case, you have a new instrument under warranty, so go and require the exchange or money back. 500 USD is not a small sum. 

dougw Jan Cumps  Andrew J PavelKCZ anniel747 

 I thank you all for taking the time to give me valuable advice and if I find a solution I will share it with you.

That's actually low-cost. It costs a bit more than that in Europe. You could have bought it from an official Rigol distributor from (say) Europe, and got it shipped to you, I suspect for about $600-$650 including shipping, if you were OK to pay import duty on it when it arrived to you.

I know that doesn't help now, but for future test equipment purchases above (say) a couple of hundred $, it might be safer to pay the extra amount to buy from an official distributor. But even with a distributor, you'd still likely have to swallow any shipping charges if things go wrong and you need a warranty repair. 

Yes, this device is under warranty in China for three years, but it does not have a warranty in Egypt.

I must admit that I do not know how the customer protection laws works in Egypt, but I am almost sure that if you will contact the China vendor and ask for exchange or money back, they will arrange for equipment exchange.

The Rigol service just sent me the mail and said that "please try the following solutions:

• Press the power button and quickly press the BACK button on the front panel multiple times. This may reset any incorrect settings.
• Alternatively, place the latest firmware on a FAT32 USB drive, power on the device, and follow the on-screen prompts to upgrade the firmware.
• If these steps do not resolve the issue, please contact our support for further assistance by 'reply all' via this email.' But I don't know what is he meant by back button

I have a Rigol DHO924S and it comes with the same Liteon PA-1650-58 supply.

It works.

It is quite slow to boot up - maybe a minute or so.

MK

michaelkellett  Ok, thank you. Do you know which the Back button in the front panel that Rigol service mean

It's not clear in the 924s manual but I think they might mean this key:

MK

This one

Do you know how to ubdate scope firmware, I download the file from Rigol site "" rel="noopener noreferrer nofollow" target="_blank" data-e14adj="t">supportint.rigol.com/.../software-firmware-download.html"

This one

Do you know how to ubdate scope firmware, I download the file from Rigol site "" rel="noopener noreferrer nofollow" target="_blank" data-e14adj="t">supportint.rigol.com/.../software-firmware-download.html"

It looks to me as if the scope must be working to update the firmware - you put the new code on a USB stick, plug into the scope and open the file. Which means you need to have it working well enough to work the disk management functions.

There is a .pdf file (which may have cold boot instructions) at the link you gave me but it won't let me look at it (no password) but you might be able to look.

There are some more ideas here:

www.eevblog.com/.../

MK