cd changer - baffled

Hey all,

I installed an old Sony CDX-U300RF 10 disc changer in my 94 Toyota just yesterday and everything went smoothly and it was functioning perfectly.  This morning however the display stays blank all the time, the changer console does still receive power as it responds to eject commands but when the disc caddy is put back in it doesn't scan the cds anymore.  I checked the wiring to the head unit and the power still gets there (pretty basic, just the pwr, gnd, mem), i checked the Unilink cable and no problem there, I checked the display unit and still no problem in the wires there.  I've tried resetting the unit and that does give a bit of motor activity from the console but still doesn't play.  The display always stays blank now, doesn't even display the time.  Inside the head unit nothing seems burnt, no excessive heat.  I've found a diode near the antenna connections that seems burnt by testing with a multimeter; bypassing that gives a bit of a signal on the radio (it's RF of course) but notthing more. 

Sorry for the length of the message, but i really have no more ideas. Anyone?

thanks for any ideas 

So the changer will let you eject the magazine if you press the eject button directly on the changer, but you can't do anything from the changer's display?  And the display itself is blank?

I saw a problem like this before and it ended up being a damaged/defective display unit.  Swapped it out for another one and it worked right away.

I checked the manual for this and there's a power select switch on the modulator and apparently you have to have it set to "on" or else the unit won't turn on by itself.  If you have it set to "off" you have to push the power button on the display to turn everything on.  I doubt this will help you at all but I just thought I'd mention it anyways just in case.

The reset switch you pressed was located on the display unit, right?  Sometimes there's also one on the changer itself but according to the sony manual, when the display stops responding you're supposed to press the display's reset button.

Here's a link to the manual in case you don't have it

That's right.  The eject on the changer works and the reset on the display also.  Those are the only two things that do anything. 

What i found weird was that it worked fine yesterday and now is dead.

I guess I'll try to get it tested.

Thanks a lot for the info and the manual ,i wasn't able to find it before.