I didn't know the 440 had a power light. My 1100 power light is burned out also. But I do have the 1100 service manual. I'll check what you said when I get a chance.
Edit: I don't think the 440 has a power light the way the 1100 does.
Huh, I thought they all had the green light.
I had the 300 system back in the late 80's (till it was lifted-thank good for renters insurance!!), and they all had green power lights.
Sure let me know, I think the Alps is sealed, but can taker a closer look.
The 440 is probably the best sounding proton tuner.
Proton did make a dual mono preamp, hard to find and expensive, but it's supposedly a set up from the 1100-which is a very good sounding unit, especially given the used market price.
I have it driving a H/K PA2400, and as mentioned very natural sounding-not tube, not S.S., just sound great, and very quiet.
I was using a PT2300, also very good sounding, but has a tendency to sound bright at times-not needed with ESS AMT3's and Great Heils!.