Chris, ours went the same way. I called Lowrance intending to buy a new 'un, explained the situation, sob story etc. They said that they ran a service exchange program which got you a LCG 4000 for about 100 quid. The lcg 4000 is quite a bit smaller than the 3000 & I had to make up a bezel to cover the old fixing holes. The 3000 has a reputation for being flaky, beware if you buy a secondhand one.
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: See rule#5