Problem with sound car decoders

I have several locos & sound cars with Tsunami decoders that I have been using for quite a while.

This last time I tried to use them I had a problem I had never had before, & which I have been unable to correct.
I hope someone on here can help me figure it out.

The problem....
The horn/whistle function will not work properly.
When I push the function key, I either get nothing at all or a very short weak blast.
The bell will sound on all of them, but the whistle/horn will not work properly.
The function is working properly on all my other sound decoders...Digitrax, QSI,TCS,Paragon 2, all work fine.

I have read everything I can think of and racked my small brain trying to figure out what has happened since the last time I ran trains (just before Christmas)

Can anyone shed any light on this. I am stumped!!

Thanks in advance for any help anyone can give me.

 

have you cleaned the wheels and checked that all the contact points are good?

 

Actually I have been trying the horns while the locos/sound cars are setting still on the track.

 

Please let us know about the speakers you are using. Also try resetting it to default factory settings.

 

2 or 3 different speakers. Some are the OEM Athearn (in the Big Boys & the Challengers) Some are in sound cars. All do the same thing.

Again, only the horn/whistle function seems to be affected. All other sounds seem to work fine.