Well, for one, we'd not be able to tell you what's wrong. That takes time on the bench doing various tests. No way to tell you if it's a minor component or a major "chip". We don't service them any more because they have been out of production for so long that the unit's specific components are no longer available.

The replacement for the R129DP receiver is the R149DP. Here's the stock number and MSRP:

FUTL0911 R149DP PCM 72MHZ W/O CRYSTAL US$224.99

These parts can be ordered through any hobby retailer who sells Futaba systems and accessories. It's discounted a lot by various sellers. Check your favorite retailer for pricing.