12v ac dc converter

That AC-DC adaptor should work. It supplies 500mA and the detector only needs a max of 425mA. Hence either the AC-DC adaptor is faulty or you have + & - interchanged or your detector draws more current on switch-on. (I assume the detector still works in a car?) If you can't figure out which of the above, maybe try a larger 1A output rectifier (ac-dc adaptor).

Yeah - this site blocks eBay links. Just supply the item number - but a title/description is a handy confirmation!! Maybe you have an old computer supply hanging around... that has AMPle 12V capacity... But that #230345927313 is a cute plugpack. Yes - it should work. It's 1A is more than double the detector's "max average" consumption. And I should think it will handle the inrush current.... But if the inrush (power up) demand is higher than what that unit can supply... Have you tried using a capacitor on the output of the 500mA unit? (EG - PSU on with capacitor BEFORE connecting the detector.) That should solve inrush problems.... providing the inrush for the charging of the cap doesn't blow the PSU.... The cap should be at least 16V rated - preferably 25V. As big as possible for inrush ride-thru, but.... As small as possible to not overburden the PSU upon initial charge up.... Probably around 470uF? But I reckon whatever you have - whether 10uF or 10,000uF - give it a try. A big cap might blow the PSU if it isn't self limiting, but if it's useless anyway.... (or cheap enough to replace).

WOW! If I found 5A units like that - and that cheap - I wouldn't have bought my $10 PC supplies. (I use them for 12V watertank and sump pumps using the 2 level-limit switches in a simple SPST latching relay configuration.) But yeah - 5A should definitely do it LOL! I'm curious as to why the other did not work - faulty PSU or connection; sensitive PSU; or undocumented inrush current? But I'll leave that for the cats.... it'll be one of the above; big deal.... For that price and its nice beefy over-rating, I think you got your best solution!