[R-390] line filter for EAC R390A

[2002tii]

Dick wrote:

>Are you saying that grounding through the third wire of the line
>cord is not sufficient ? Maybe that's why the thing kept popping
>the GFI.

No, the third wire of the line cord is connected to the radio 
chassis, so connecting the third wire to a proper ground makes the 
leakage current flow down the third wire to ground rather than 
waiting for you to make the connection and get a shock.

However, as others have said, GFI outlets sense the imbalance between 
the hot and neutral current flowing between the radio and the mains 
supply and trip if there is any significant ground current (i.e., 
current flowing "into" the hot wire but not flowing "out" the neutral 
wire) -- so the leakage current down the third wire causes an 
imbalance (current flowing "into" the hot wire and "out" of the third 
wire) and the GFI trips.

The best solution (IMO) is to remove the radio's line filter -- this 
solves both the shock risk and the GFI problem.  You can either do 
without it, or replace it with a more modern line filter (such as the 
IEC-rated types suggested by others).  If you are really a stickler 
for looks, you can build the innards of a modern filter into the old 
filter housing.

Another solution is to plug the radio into a non-GFI outlet, making 
sure the chassis is securely grounded, either through the third wire 
of the line cord or otherwise.  However, be aware that the "ground" 
terminal of outlets in older homes may not really be a good earth ground.

As long as we're on the subject of grounding, note that a really good 
earth ground -- say, a 12 foot length of 1" copper pipe driven into 
the ground and connected to the radio chassis by no more than 20 feet 
of # 10 copper wire (or, better yet, 2" copper ground strap) often 
improves reception (by providing a counterpoise to an unbalanced 
antenna) and reduces the impact of local electrical noise.

Best regards,

Don