Fender CYBER-TWIN HEAD, Service Manual, Page: 4 / 44

CYBER-TWIN HEAD
Step by Step
Fender Cyber-Twin Troubleshooting Guide for Hardware Problems
NO AUDIO
Setup: Follow the instructions as stated under notes 8, on the Cyber-Twin Head Main Schematics
(0057498000 Sheet 1).
1. Turn on the Power to the Cyber-Twin.
2. Does the Jewel LED come on?
1.1 If the Jewel LED does not come on, but there is Audio, check the Jewel LED.
1.2 If the Jewel LED does not come on and there is no Audio, check the Power Supplies.
2 Does the VFD ( V acuum F lourescent D isplay) come on?
2.1 If the VFD does not come on, but there is Audio, check the VFD.
2.2 If the VFD does not come on and there is no Audio, check the Power Supplies.
2.2.1 If the Power Supplies are OK then check the Ribbon cables.
2.2.2 If the Ribbon cables are OK, swap the Host board.
3 If both the Jewel LED and the VFD come on, but there is no Audio, then check the speaker
connections. Remove any rear panel audio connections (Headphones, FX etc).
4 If the Speakers are OK and there is no Audio, then check the Power Supplies.
5 If the Power Supplies are OK, check for Audio on Effects Send.
5.1 If there is no Audio on Effects Send.
5.1.1 Check for Audio on U7 Pin1 on the Main PCB.
5.1.2 If there is Audio on U7, then swap the Analog I/O PCB.
5.1.3 If there is no Audio on U7, then check for Audio on P1B Pin 7 & 8 on the Host PCB.
5.1.4 If there is no Audio on P1B Pin 7 & 8, then troubleshoot the Pre-amp section on the
Main PCB.
5.1.5 If there is Audio on P1B Pin 7 & 8, then check for Audio on P1B Pin 1 & 2 on the
Host PCB.
5.1.6 If there is no Audio on P1B Pin 1 & 2, then swap the Host PCB.
5.1.7 If there is Audio on P1B Pin 1 & 2, then troubleshoot the Distortion section on the
Main PCB.
5.2 If there is Audio on Effects Send.
5.2.1 Check for Audio on P3B Pin 7 & 8 on the Analog PCB.
5.2.2 If there is no Audio on P3B Pin 7 & 8, then swap the Analog I/O PCB.
5.2.3 If there is Audio on P3B Pin 7 & 8, then check for Audio on P2B Pin 1 & 3 on the
Host PCB.
5.2.4 If there is no Audio on P2B Pin 1 & 3, then swap the Host PCB.
5.2.5 If there is Audio on P2B Pin 1 & 3, then troubleshoot the Power Amp section on the
Main PCB.