Cary Audio Design CAD 211 FE - Manual (Page 13)

TROUBLESHOOTING GUIDE
SYMPTOM CAUSE REMEDY
Hum or “Buzzing” in
speakers
Ground loop
300B tube with high plate
current too high
Intermittent or poor connection
of interconnect
Install 2-pin adapter
on AC cord to float the ground
Check bias of 845’s. If high,
readjust to proper bias setting
of 100 mA
Replace bad interconnect cable
“Popping” or “Spitting”
noise
Noisy tube
Check bias of output tubes
If noise is in one channel
through the speaker, swap one
section of tubes at a time until
the noise swaps channels.
Replace the noisy tube.
If high or fluctuating rapidly,
replace output tube
AC fuse blows Line voltage surge Replace fuse
Tube fuse blows Shorted tube (300B &
845 have separate fuses.)
Replace tube
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