The following from avweb.com:

By Mary Grady
Newswriter, Editor [avweb.com]

Garmin issued a service alert on Wednesday warning users of some of its
brand-new GNS 430 and GNS 430A units not to use them for IFR operations. It was
the company's second service alert this month to include those units. The
panel-mounted units have a problem that could cause the unit to trip the
aircraft circuit breaker, rendering the unit inoperative, Garmin said. Only
units manufactured between Feb. 23, 2005, and March 21, 2005, are affected. If
you have an affected GNS 430 unit, contact your local Garmin authorized service
center immediately, and they will make arrangements to modify or replace the
unit, Garmin said. The GNS 430 is a WAAS-upgradeable IFR GPS, Com, VOR, LOC, and
glideslope with color moving map all in one unit. The 430A version has a 16-watt
instead of 10-watt radio.