I own a 1992, Acura Legend. The car came with an antenna broken off but the radio still worked, it just took a few minutes to turn on. Then when it started getting cold outside the radio completely stopped working. I have now gotten a new after market antenna installed and that is all installed properly. But for some reason the radio still will not play. sometimes when i turn the radio on the display wont turn on properly and the letters will be all mixed around. Do I need to just buy a new head unit?

yes get a new headunit. while your at it put a system, then a ground kit, and then and then you can get a new exhaust and then a new intake and then a new engine, and then NOS.

i don't understand why you have purchased after market antena as they are not alway of good quality.I would suggest you to buy a new head unit.