Jump to content
We Need Your Help! ×

IGNORED

Schematic for Hitachi KM-1520ZD needed


philbar73

Recommended Posts

Generally output stages that aren't transformer isolated use an electrolytic capacitor to do the isolation. I have never seen a car radio that used a transformer, all I have seen use an electrolytic capacitor. Is the impedance of the power amplifier on the connection that would go to the radio very low, like below 8 ohms?

KM-1520 Car Radio Hitachi Ltd.; Tokyo, build 1973, 4 picture

Edited by Mikes Z car
Link to comment
Share on other sites

The output (speaker leads) measure .9 ohms. The only thing I can think of is I'm testing a winding on a transformer. If it was a capacitor I would think that I would see the reading changing. It solid at .9 ohms in either direction. The white and black lead is tied to ground, the case of the radio.

When I connect the radio to the amp there is no output. If I lift the ground wire and just connect the white lead from the radio it works. I'm an electrical engineer and would like to understand what I'm dealing with. The power amp has a speaker level input but it seams the - input on the power amp will not work when grounded. I put a small audio transformer between the radio and the power amp to isolate the ground and it acts the same. I don't understand what's going on.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.