Mark Levinson No. 36 DAC,,,NEED HELP

First off are you getting any lights at all when it's in standby or powered?

Before we start at the dangerous end (power supply), to gauge your skills, do you own a volt meter (DMM) and know how to use it on mains, without frying yourself.

Cheers George

NO CODE" is displayed upon power-up.

Sorry misunderstood, have you asked ML (Harman) what this "No Code" means
Email: csupport@harman.com
as you just about asked on every other forum I noticed.

Cheers George

You didn't give enough information. Is it displaying the code with a  transport? I would try another transport. If the code is displayed without a transport plugged in, then you have to give Harmon or Pyramid Audio a call if the owner's manual does not indicate what that code means. 

Good thinking  gs5556, could just be a bad transport sync. Try different  transports hooked up.

Cheers George

gs5556
when it  power-up just show  "NO CODE" on the screen, and all the button not working. 
someone said it is locked.

It maybe locked if you don't have a good transport attached? 
Cheers George

how to unlock it?

You still haven't responded to the question we both asked, have you got a known good transport hooked up to it??

 As it may lock if you haven't.

Cheers George

I used to have one.

A (defective) transport without a signal will not show "No Code".

I've never seen that error in all the years of owning one.