Fisher 400CX-2 Stereo Extension pot cleaning

kkib

Member
Hi everybody,

The Stereo Extension pot on my Fisher 400CX-2 is acting strange. The left channel is leaking into the right channel. I tried cleaning it with Deoxit but that didn't seem to work. I am considering to open and try to clean it and I was hoping to hear from someone who has done this before to see how difficult this job is. If I mess it up is there a source where I can find a replacement? Thank you for any help.
 
Hi everybody,

The Stereo Extension pot on my Fisher 400CX-2 is acting strange. The left channel is leaking into the right channel.

I think you mean "Stereo Dimension?"

As I understand it, that pot is designed to "blend" left and right channels. Or separate them if required. So, I'm not so sure what you're hearing is out of the ordinary. If set to "Normal" the control will permit the sound to be reproduced as recorded.

In case you don't have it, I've clipped the section of the manual describing the function of the control:

Stereo Dimension.JPG
 
And with the Control Full Clockwise (Stereo) the pot/switch is effectively out of circuit. Or it's supposed to be. I put it to FULL Stereo and leave it there on my X-202 and X-101-B.
 
Different kind of circuit, Larry. On the 400CX-2, it is an active Stereo Dimension control, so that normal stereo results from a centered control. From there:

1. A counter clockwise rotation begins to blend the two channels as the passive Stereo Dimension controls do on your amplifiers. But --

2. A clockwise rotation actually works to spread the two channels further apart (expand them) than the way they were originally recorded, by inserting each channel's common mode signal in an out of phase fashion into the other channel. Kinda neat with a very few recordings, weird with most, and just doesn't even work with mono signals, since it effectively shorts out the signal in both channels.

Dave
 
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