Reply to "What is this about?"

I came across this warning in a QS-3000 user guide (1999): "Early Z-750's packed in yellow boxes produce damaging voltage spikes and overvoltages, and are not recom-mended. Later Z-750's packed in red boxes deliver a lower voltage and are safe to use. To determine which Z-750 you have, attach a PowerGuard [discussed in a recent topic] to the transformer and turn up the power. If the red light on PowerGuard stays on steadily, you have the early Z-750 that is not recommended. Damage to QSI sound systems and reverse units from these early transformers is not covered under any QSI warranty."