ESU LS decoder makes tick-a-tick-a-tick-a sounds.

[Trnsrus]

I installed 58925 decoders onto a pair of Atlas N scale U36B/U36Bs and loaded the matching OEM sound project from the ESU website. During test running and speed matching using Decoder Pro, the decoders performed properly. Shortly thereafter, one loco stopped producing horn, bell and prime mover sounds and instead played a soft, rapid tick-a-tick-a-tick-a sound. I exchanged the decoder with that of the other locomotive and the problem followed the decoder. Both locos played sound properly when using the "good" decoder. Reloading the sound project did not fix the problem. Is there anything else I could try before sending the decoder to ESU?

[peteski]

I installed 58925 decoders onto a pair of Atlas N scale U36B/U36Bs and loaded the matching OEM sound project from the ESU website. During test running and speed matching using Decoder Pro, the decoders performed properly. Shortly thereafter, one loco stopped producing horn, bell and prime mover sounds and instead played a soft, rapid tick-a-tick-a-tick-a sound. I exchanged the decoder with that of the other locomotive and the problem followed the decoder. Both locos played sound properly when using the "good" decoder. Reloading the sound project did not fix the problem. Is there anything else I could try before sending the decoder to ESU?

If the motor and light function properly then it sounds (pun intended) like the audio section of the decoder has failed.  Probably the power amplifier. Any chance the speaker leads were shorted or connected to either rail pickup accidentally?  You did all the troubleshooting already.  Probably time to contact ESU.