pa21
Troubleshooting
Some tips:
• No output. Power is on, but power LED is off and tubes do not light up.
AC cable makes bad connection in IEC connector. Please check.
• No output. Power is on, but power LED is off and tubes do not light up.
Mains fuse is out. Replace fuse as per instructions on page 5.
• No output. Power is on, but power LED is off and tubes do not light up.
Mains fuse is not out. Thermal protection may have switched off power transformer. If so, the power ampli-
fier will switch on again after internal temperature of power transformer returns to normal. Overheating
might be caused by higher environment temperature than normal or heavy use.
• No output. Power LED is on and tubes do light up normally.
Check preamp, input and output wiring; if all seems to be OK check power amplifier.
• Hum or noise coming from one channel.
Noisy tube. First swap the 6SN7 tubes left to right. If noise follows tube swap, then you have found the
problem tubeset. Now swap one by one from left to right. If noise follows, you have found the problematic
tube.
• Hum coming from one channel.
Possible bad output tube. Swap the output tubes in pairs from right to left. If hum follows the swap, swap
the far left and far right tubes. If the hum returns to the original problem channel, you have found the
problem tube. If not, swap the inside output tubes left to right.
• Noise/distortion coming from both channels.
Tubes may be in need of replacement. Read page 6 for tube basics and replacement options.
If you try these possible solutions and problems persist, contact us or your local distributor for further
investigation.
Mystère
