Yes Ken as almost always is right... forgive me Ken I say almost cause I sure know sometimes I am wrong.
If your cabinet has an isolation transformer, it is still not a bad idea, just not needed as the monitor has a switch mode power supply which offers the protection of an isolation transformer on all components after the transsformer.
But if you are troubleshooting areas before that like the bridge rectifier,,, then you should definitely use an Isolation transformer.
Always feel free to e-mail me in regards to questions on our monitors.
thanks
Rick
Rick@niemandisplays.com