I'm trying to figure out why my new solid state regulator puts a voltage out to the field of the alternator when it senses the hot wire of the radio. This causes the alternator to get hot and puts a drain on the battery.
I recently installed a new ext regulator because the old relay type was putting 16 to 17 volts into the sytem at 3000rpm's. The next day my battery was dead. This all occured right after I installed a new radio that needs battery power to keep the clock and presets active. If I disconnect the yellow radio wire from the batt term of the fuse block for the radio...the voltage to the alternator goes to zero and everthing is fine. I've replaced the regulator and got the same results. I'm thinking that maybe these new voltage regulators won't work in my car????? This all occurs with the key off. Everything is fine when running the engine. Also bought a new battery and alternator since I needed them anyway. Any suggestions or comments would be appreciated.

I recently installed a new radio along with a new solid state voltage regulator and have no problems!.....You need to go over and check your radio wiring, it's shorting out somewhere!.....There are 2 power sources that the radio needs, a constant power and a switched power which works off the ignition switch.

I think you're correct in that it's in the radio wiring. I used the original yellow wire from the AM radio for the ign. power wire, and the original black wire for the ground. I ran the constant power wire to the batt term on the fuse block. What's happening is when the radio is hooked up it somehow makes it seem as though the key is turned to the ign position which inturn puts voltage to the alternator. I went through the charging circuit and everything works fine until I hook up this radio. It's a Retro-Sound and I really like it if I can figure out how to make things right. What radio did you use?

What radio did you use?


I have the Custom Autosound Concours, USA-230, AM-FM stereo.:thumbsup:

Nice radio. A little more investigation today totally baffeled me. I disconnected the radio entirely and went about checking things again when I discovered that when the key buzzer goes off, 12 volts appears on the field of the alternator. I started checking out the horn relay which I believe is original and it was full of rust. I replaced that today, but have the same results. With the key in and the buzzer going..12 volts to the alt. Key in acc position..12 volts to the alt. Key in the on position..12 volts to the alt. So, I think I have a problem somewhere in the wiring or the ignition switch. Rigth now, I wired the radio directly to the batt term. and ign term. of the fuse block and everthing is fine, but I can't play the radio in the Acc. position. I can live with that for now until I have more time to dive into this with both feet. Thanks for listening.

Steve