Mark Levinson equipment setup

First plug in the 390S, then the 380s, then turn on your 336 with all components linked. You will turn on your system by using the 390s first either the remote or unit will do this, when activated all others should come out of standby. Put all components back to standby on the 380S.
I've had this system myself, and this was Madrigals directions. Make sure you let the 390s cycle up before plugging in the 380s.

Assuming you've properly enabled the link functions on your 390s, the only trick to this is to make sure you have your CAT5 cable plugged into the 390's master/slave out port and into the 380's slave port. The 390 MUST be the master in the chain or nothing will work.

If you have your cable plugged in correctly, and if you are using standard category 5 patch cables (pin-to-pin, straight thru), you should have no problems. I say should, because everyone I know usually runs into some problem with this when they set their system up.

When I had reached my wit's end, Madrigal suggested that after I had enabled the link functions on the 390s and attached the com cables, to power off the 390 and unplug the 380. Then power up the 390 and plug in the 380 (in that order). The resulting cold-boot is supposed to re-establish communication. As it turned out, my problem was a bad patch cable to the power amp, but you might want to try this if nothing else works.

Also, if the power amp doesn't powerup automatically when you turn the preamp on, I found out that I had to put the amp into on mode manually (by pressing the button) with the preamp on the first time. THEN when I powered the preamp off, the amp switched off as well.

Are you sure you have the correct link cables?
Source to preamp is different from preamp to amp. (And for monoblocks, yet another type of cable is needed from mono to mono).

After I got the correct cables, I never had a problem linking my components, even when all of them were already powered up before I connected the links.

I've had similar problems with my 380s, 36 and 37. It takes me a few tries of plugging in and unplugging the connectors and powering up. I have not been able to find the logic in what sequence works. I diligently took notes one time after a power outage, and once I got it running I tried that sequence again--it didn't work. I have not been able to find anything in the manuals about powering up to get the communications to work properly, the manuals almost imply that it's a completely automated procedure. Have you by any chance contacted Madrigal? I would be interested in knowing what they had to say.