ummmm r2r picking up radio signals?!

[BOJAX]

hey,

right now I have my deck set to 2 channels (it is a 4 channel deck) but I am listening to the rear channels and i am picking up radio signals! They disappear when i switch to 4ch.
What on Earth is going on?

is there a way to toally eliminate it?

 

[arjoll]

right now I have my deck set to 2 channels (it is a 4 channel deck) but I am listening to the rear channels and i am picking up radio signals! They disappear when i switch to 4ch.
What on Earth is going on?

Sounds like you're getting RF leakage, the fact that it disappears when you switch to 4 channels makes it sound like something is 'floating' rather than being earthed/grounded (either directly or by a resistor).

Try cleaning all the switches, especially the one that you're using to switch between 2 and 4 channels. For any other fixes you'd probably need the schematic. In areas of high RF putting ferrite beads on the input/output leads may help. How close are you to the nearest AM broadcaster? (if you can hear a programme its AM, if its just a buzz its FM)

 

[BOJAX]

it's definaltly AM broadcasts.
in fact , they seem to be around the AM 680 area
what should i clean the switches with?
both stations are downtown
we do have some radio towers nearby but i dunno if those are for the particular stations i am hearing
all the downtown stations use the CN tower (i am in toronto)

 

[arjoll]

it's definaltly AM broadcasts. in fact , they seem to be around the AM 680 area what should i clean the switches with?
both stations are downtown we do have some radio towers nearby but i dunno if those are for the particular stations i am hearing all the downtown stations use the CN tower (i am in toronto)

Surprisingly enough I'm not really familiar with the towers in your area

There are fancy solutions to clean switches with - if you check https://homerecording.com/bbs/showthread.php?t=131837 there's info on an Akai restoration project that cjacek had with info on cleaning. I just used CRC CO contact cleaner in an eyedropper when fixing up my GX265D but I don't believe that this is recommended practice.