Total posts : 45366
Sounds like you are on the right track with troubleshooting this. It is very possible that if you are using the speaker or phone output from the laptop that you are over driving the transmitter. If it works, the attenuation cord would be a nice and simple fix.
I recall mistakenly plugging into my portable CD player’s headphone jack instead of the line jack when I was trying to dub some audio and the result was pretty miserable.
Let us know how this turns out.