I've had an RM-VL600 for years and have been quite happy with it. The other day all the buttons in the rightmost column of buttons (power, CBL, AMP, 3, 6, 9, etc. through to the pause and system control D buttons at the bottom) stopped working altogether, so I figured it was time for a new one.

I bought an RMVLZ620 since that seems to be the current model. And aside from the annoying additional buttons required to learn commands, it seems to be working well (I programmed it for my Samsung TV, FIOS STB, Sony DVD changer, Sony VCR, Roku box, and even my LG air conditioner). But there is ONE particular command I just can't seem to get the 620 to learn.

It's the command to select the "DVD" input on my decade-old Harman Kardon receiver.

My Sony 600 learned this command without any trouble (and I'm still able to program it into my partially disabled 600 as long as I use a device select button other than the dead CBL and AMP buttons). And the 620 seems to learn all the other buttons I've tried to program from the HK remote.

But I cannot for the life of me get the 620 to learn this particular command. I've tried "teaching" the 620 the DVD input command from both the original HK remote and from the 600, but it just doesn't seem to learn it.

Any suggestions? I suppose I could go back to the default Harman Kardon button setup for the 620, which included the DVD input on one of the number keys, but I find it hard to remember (I wanted to redo it so that buttons 1-4 were Video 1 through Video 4 and 5 was DVD, which I find easier to remember).

Are there simply some IR sequences that the 600 could learn but the 620 can't?