280z Hitachi Radio

[NC280z]

Hi everyone,

 

I'm (still) troubleshooting the stock radio in my '75 Z, and could use some input. My radio powers on, and the speaker (which is new) emits some sound, but it's barely audible. I took the multimeter to my radio, and found that the antenna is receiving voltage (which is causing interference, and thus the low speaker output). I've got a wiring diagram for a '76, but the wiring colors on the diagram don't match my radio's.

 

Here's the wiring and continuity of my radio, hopefully you all can help figure out what's messed up. I've got 6 wires, white, white/black, blue, black, red/blue, green/white. The power antenna is removed. White (power for speaker) has continuity with the antenna ground, and with the speaker's negative (white/black) wire, and with the ground wire. I know that black is ground, and blue is power, but what are the green and red for? Also, what should have continuity?

 

I'd like to keep the stock radio, so any help is greatly appreciated. Thanks in advance to all!

[datzenmike]

Barely audible means low volume. Even static should be loud if the radio is working properly. The antenna won't cause low volume.

 

Try another speaker.

Try reversing the speaker leads.

Radio is well grounded?