[RFI] Oven RFI help needed

Jim Brown jim at audiosystemsgroup.com
Wed Apr 22 22:03:28 EDT 2020

On 4/22/2020 4:19 PM, David Eckhardt wrote:
> Find the wiring harness (likely a ribbon cable) that services the touch
> panel and install multiple ferrites to that cable, all cables to that
> module.  No promise, but clearly, you've isolated the problem module.

This assumes that the susceptibility is that internal wiring.  That's 
possible, but my money is on common mode on external wiring -- it's the 
best HF RX antenna, the cause is often failure to terminate the green 
wire properly inside the equipment, and it's the easiest to fix without 
making it a science project (and voiding warranties).

And remember -- what the power and EMC world calls common mode ignores 
the green wire, which passes through conventional power line filters, 
and is usually where the noise current is! If a conventional filter 
helps, it's usually because it's internal and properly bonds the green 
wire to the shielding enclosure, NOT because of it's design as a filter.

73, Jim K9YC

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