Delco radio not working
06-06-2015, 08:42 AM
#1
Burning Brakes
Thread Starter
Delco radio not working
I bought a low mileage 1972 with an after market radio installed. I also have the original amfm mono radio which I want to install. I was told the after market install caused no damage, but I had to replace the speaker connectors, the power connector and the amp was also gone so I bought a clean used one; correct single ds501. All re-wiring was done properly with solder and heat shrink. I have power to the unit and the light works, but no sound; not even a buzz or static. Speakers are the original 10 ohm. Even tried another (1971) radio with the same result. Yes the radio case was grounded. Both radios were sitting for a number of years, but are not beat up, rusty and are very clean. Could the amp be bad? Am I missing something?
06-06-2015, 08:51 AM
#2
Team Owner
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Test the 501. It's the final audio output for the radio.
06-06-2015, 09:14 AM
#3
Burning Brakes
Thread Starter
This is what I found so far...If you're not an EE or electrical tech with bench experience and/or access to a transistor checker, you can probably phone around to local radio/TV shops to find someone who can test the 'suspect' DS-501 for you (along with your replacement). I think I'd start by verifying the integrity of the existing speaker drive xsistor before going on what might be a wild goose chase for a replacement....
How do I test it? I also found the blue is the collector, green is base and yellow is emitter.
How do I test it? I also found the blue is the collector, green is base and yellow is emitter.
06-06-2015, 05:18 PM
#4
Instructor
Want to start with a more simple test? Since the chance of a C3 DS-501 being totally bad is rare to never, you can take a flash light battery and put it across the individual (left and right side) green and black speaker leads. Disconnect the radio first not that you would hurt it. Each time you connect it you will hear a thump sound. No, you won't hurt the speakers. No thump - it's open.
Or use an ohm meter which will read approx 8 dc ohms (with the radio disconnected). No continuity - it's open.
Original 4X6 C3 speakers are absolutely notorious for developing open voice coil leads on the surface of the cone under the black liquid tape material.
Good hunting!
Or use an ohm meter which will read approx 8 dc ohms (with the radio disconnected). No continuity - it's open.
Original 4X6 C3 speakers are absolutely notorious for developing open voice coil leads on the surface of the cone under the black liquid tape material.
Good hunting!
06-06-2015, 06:23 PM
#5
Burning Brakes
Thread Starter
Thank you Jerry. Tested both speakers with a D battery; no thump and no reading with the ohm meter.
Want to start with a more simple test? Since the chance of a C3 DS-501 being totally bad is rare to never, you can take a flash light battery and put it across the individual (left and right side) green and black speaker leads. Disconnect the radio first not that you would hurt it. Each time you connect it you will hear a thump sound. No, you won't hurt the speakers. No thump - it's open.
Or use an ohm meter which will read approx 8 dc ohms (with the radio disconnected). No continuity - it's open.
Original 4X6 C3 speakers are absolutely notorious for developing open voice coil leads on the surface of the cone under the black liquid tape material.
Good hunting!
Or use an ohm meter which will read approx 8 dc ohms (with the radio disconnected). No continuity - it's open.
Original 4X6 C3 speakers are absolutely notorious for developing open voice coil leads on the surface of the cone under the black liquid tape material.
Good hunting!