Newbie: Playback ok, but recording with an echo

[Shmeinak]

Hi, I hope I can explain my problem and get an answer as I have been 'audacity disabled' for close to a month now.

I used audacity until recently by plugging in my tape recorder (into the line-in) and playing the tape while hitting the record button on audacity.
Whenever I used to do that both the top and bottom 'lines' that show the sound input would show wave forms. A few weeks ago suddenly only the top line is showing a wave form. When I play the tape without recording the sound comes through the computer fine, but as soon as I hit the record button it gets an echo, and still no wave form on the bottom line.
I am set for stereo, and have unchecked overdub.
The information on the left side of the audio tracks says:
Stereo, 44100Hz
32-bit float
both mute and solo are not hilighted
Both the -/+ and the L/r are in the center.

I am not sure what other information to give so that someone can help me.

Thank you in advance from a desperate newbie.

[kozikowski]

I suppose it's possible you damaged your sound cable or the connections.

You did not change the computer, right?

Start Audacity fresh and go into record. Leave the tape machine off. Behind the computer, unplug the audio cable and plug it back in firmly several times. Stop Audacity.

Control-F to see the whole track. Do you see clicking and disturbances on both tracks -- both blue waves? If you do, then the problem is the cable or the tape machine. If you don't, then the computer may be doing something wrong. We are intentionally creating very minor damage to make sure the system is working OK.

It's an odd but valid servicing tool.

Koz

[Shmeinak]

There are some markings on both tracks, but the upper one has much much more than the lower one.
The one thing that I did between the last time it worked and now that it doesn't, is that I installed 'silverfast ai'. initially silverfast didn't work and the instructions from them said that I should disconnect any printers or scanners I had then install silverfast in case there was a conflict.... PS my MFC faxes from my computer now, but does not print even though it says it is online.

I just tried uninstalling audacity, turning off my computer, then reinstalling it with the same problem.

The part that really confuses me is that it plays clearly until I hit the record button - that is when it gives the echo and only the top track shows a waveform.

Thanks again for your help