Jerry Roubos

1986 corvette
I have been working on my Bose audio system all day.
Fuses are ok,
Turn radio on antenna gos up and station appears.
No sound or popping at any of the speakers.
Turn radio off and time appears.
No voltage at speakers with radio on.
I figured it must be the amp relay so I bought a new one previous to taking the whole car appart.
I plug the new amp relay in, turn on the radio and the radio fuse blows immediately. I take the amp relay out and everythind is as it was at the beginning, plug the amp relay in and the fuse blows again.
I took volyage readings at the amp relay plug with the radio on.
The results were orange #1 +12v
Pink #2 +12v
Black #3 ground
Pink/black #4 No voltage
Does this indicate a bed speaker amp?

Jerry Roubos

Bought another amp relay today and tryed that, still blows the radio fuse.
Pulled the radio back out and checked all connections, every thing is hooked back up correctly.
Checked voltages at the connector that the amp relay plugs into,
everything checks out as the shop manual says.
Pulled both rear speakers visualy checked, cannot check the voltages because of the fuse blowing when the relay is pluged in.
Does anyone have any advice beside scrap the bose system? I am trying to f=keep the car 1986 stock.

Jerry Roubos

I am thinking that maybe I should disconnect all the speakers and then plug the amp relay in and see if the fuse blows. I dread taking the doors apart, I beleive that is really difficult.
Now I don't know if any of the speaker amps are any good, if I had one good one I could start pluging them one at a time untill the fuse blows.
My current theory is that one of the amps has a direct short.
Can any one tell me if there is a method to bench test the speaker amps?

ZR-71

My '91 has the speakers in the door sill and when I checked my '89 the speakers are in the door panels. Pulling the door panels isn't fun but it's not the hardest thing to do. Try replacing the water pump

Jerry Roubos

Hope I don't have to replace the water pump, sounds awful.
I wonder if they could have made a more complicated audio system?
I was trained during the vetnam war to be a aviation radio tech and worked on F4 radios. These Corvette radio systems are a lot mor difficult to work on.

ZR-71

Man I'd love to just look inside the cockpit of one of those F4's
And thanks for your service back then

mikeb

How does the water pump affect the speaker amps?

ZR-71

Just comparing repair difficulties

mikeb

I know

The first read had me like,
Re-read it and, Ooooooooh, must be difficult.

fredd1

If you're bench testing the amps a good place to start (after a visual check of shorted traces and burned components) would be the caps, especially any electrolytics. To test a cap for a short, you will need to un-solder one end and use a VOM. Good luck.

Dans 85

Hi Jerry,

You either have a shorted amp or the wiring leading to them. I'd unplug the rears and try a new fuse. If it pops unplug the fronts, if not blown try plugging one of the rears back in at a time. If everything is unplugged and the fuse persists to blow you have a short in the car's wiring.

Regards,

ProjectC4

Yes, try unplugging the speakers until the short goes away, rears first since its easy. I bench tested my amps with a lawn tractor 12v battery and an iPod as signal source using radio shack alligator clips. Had all the amps rebuilt by Dr. Don's in Florida, 80 or 90 dollars each. One had to go back twice but he stood behind it. Lifetime warrantee.

AirForceOne!

Good luck! I scrapped mine!

Jerry Roubos

Step one was done todat. Both rear speaked assys diconnected. Still blows fuse.
Tomorrow I will take the right door apart, hope thats it, with myluck t will be the last one. I just hope that it's not a short in a wire.

Phat98

Nah...as an old USAF Avionics troop, I can assure you there are no tubes or tuning drives in a C4. Old F4s, yes.

Jerry Roubos

Very true how things change.

1993C4LT1

AGENT 86

You might find these useful

http://www.carstereohelp.com/stereor...etteFspk89.htm

http://www.corvettejunction.com/frontamp.html

Jerry Roubos

All of the speaker amps are now disconnected.
Fuse still blows when the radio is turned on.
Turn ignition on and the time displays ok, then when the radio is turned on the fuse pops immediately.
With the fuse replaced and the radio off the amp relay checks out correctly per the shop manual I have also tryed a different new amp relay the fuse still blows.
I removed the radio, took a multimeter and checked all the wires between the radio plugs and the speaker amps. I did not find any opens or shorts.
I am concluding that I may have a short in the radio.

I have often read the name Dr. Don on this site, how do I get in touch with him? He seems to be highly regarded.

AGENT 86

Are you sure your relay is the correct one ?
The radio fuse only powers the primary(coil) side of relay, the clk/ctsy fuse is on the secondary side, to power amps.
Is there a schematic on relay ?