No Power to Radio

Bonneville1962

Hello All----just bought a secondhand Radio/CD in almost new condition for my Caravan--the wiring was already there so i wired it to the ISO connector {carefully} switched Radio on & it lit up for about a tenth of a second then went out i checked
for blown fuses but were all ok---i switched power on & off a few times more & the same thing happened---hope someone can help---Ray.