Marantz 2500 Volume Control - Help!

I had the same symptom, and it turned out to be in my Power Amp (Marantz 140, ca. 1977). Yup, at low volumes, after the system ran for maybe 30 minutes, the right channel would start to drop out; working the preamp's volume control would put it right for maybe 20 minutes. Naturally I thought it was the preamp--tried pot cleaner, no difference. Finally I tried another (new) preamp--and the same thing happened. I even tried a third preamp (for other reasons) and still experienced the symptom. Lately I haven't noticed the symptom, possibly because I keep the power amp turned on all the time.

Puckie , Upon rereading your original letter I decided tdo the obvious , ya know , the things I learned about 25 years ago in high school and college . Jack LaLane is right " Use it or lose it !!" The intermittent loss was caused by the seldom used filter switch for frequency rolloff , namely the 9KHz . On my 1969 Fisher I Worked all switches and buttons before a listening session to get the cleanest sound I could . Well , a wife and children later I must be getting a little less fanatic about my music . Time to rekindle the audio fire , it's not too late . Once again thank you , you are an inspiration . May GOD richly bless you .FBI

Thank you Puckie , will do , very informative ! FBI

Sounds like you need to flush the pots (potentiometers). This might be a little tricky; some Marantz receivers don't have much access to them. Try taking both top cover and bottom cover off. You need to get some sort of cleaning spray, preferrably silicone based, to do the job. Also if it has a long plastic tube, the better. You need to spray the liquid into the pot itself (of course with the power turned off). Once this is done, twist the knob back and forth a few times. Do this for all pots and switches. Then enjoy your Marantz for another 10 years or so. Occasionally pot contact switches go bad but this is very rare on a Marantz. Let me know how it worked.