PrimaLuna USA ProLogue Five - Manual (Page 10)

10
Troubleshooting
Some tips:
• 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 9.
• No output. Power LED is on and tubes do light up normally.
Plate fuse may be out. Replace fuse as per instructions on page 9.
If the new fuse goes out immediately after replacement, contact us for further assistance.
• Noise coming from one channel.
Noisy tube. First swap the 12AX7 tubes left to right. If noise follows tube swap, than you have
found the problem tube. If noise does not follow, swap the 12AU7 tubes left to right.
• Hum coming from one channel.
Possible bad output tube. Swap the KT-88 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 KT-88 tubes left to right.
• Noise/distortion coming from both channels.
Tubes may be in need of replacement. Read page 8 for tube basics and replacement options.
If you try these possible solutions and problems persist, contact us or your local distributor for further
investigation.
PrimaLuna ® ProLogue Five