Technical support

Fault Finding Guide

Work through a few focused questions to identify the likely cause and find the relevant technical guidance.

Choose the closest answerPower supply DC failing

200 Series Audio All phones Low hum on speech Power supply DC failing

Recommended guidance200 Series

What to check

Remove the 12v AC fuse from the power supply and if the hum continues it would suggest the DC regulation circuit may be failing.

Replace power supply PCB

Note there are other causes of hum on the speech so check all causes before assuming this is the problem.

ID13533