96 Es300 Radio Problem

[hokiefan]

New to the forum, but I've been searching and haven't found an answer to my problem yet....any help is appreciated.

Originally, the 6-disc trunk changer in my 96 es300 went out. I bought a replacement off of ebay and the one that came in did not work and worse yet, shorted out my head unit. I cracked open the head unit on the recommendation of Pioneersubuy and fixed replaced the 6.3A fuses on the circuit board and that fixed the problem for a while....then it blew the fuses again. I kept replacing the fuses each time this happened (4 times) until one day, when trying to repair, I noticed I had used a higher rated fuse by mistake....I know, ooops. Anyway, now I have bought another Headunit on ebay and tried plugging it in, but all I get is a green illuminated screen.....no LCD display.....no radio function. At this point, I would be happy to just get my radio function back (I can live without CDs). The replacement head unit I bought off of ebay is out of a 95es300.....I've been reading that some radios need codes to unlock, but I'm not sure how I would tell if a code would be needed to unlock it....and I'm not sure if I had the code, how I would enter it for the radio to acknowledge it? Bottom line is I have no radio function now.....although I do have two radios (one which I got off of ebay and was assured works and another with an excess power input problem which has bypassed the 2 6.3A fuses). I even tried to replace the back end of my old 96 radio with the back end of the 95 model purchased off of ebay.....no luck.....same result as when I just plugged in the ebay model the first time.....illuminated screen.....no digits or radio function. Can anyone help? Thanks.