The Stovebolt Site Forums The Shop Area The Electrical Bay Fried the new radio

Well folks, I'm not sure what I did and I suspect I still have a hidden problem somewhere, so am looking for some good advice. I re-wired my '53 a month or so ago. Have had some strange problems. I followed the wiring instructions to a 't'. Converted to 12 volts. Bought a new AM/FM/Cassette radio that mounts in the dash hole from Classic Parts of America. Followed their instructions to a 't' as well and I've done my share of installing radios, so I know pretty much how to do it. However, the battery has gone dead a few times while sitting with the negative terminal disconnected. I'm at the point where I'm working to fire this truck up after 6+ years ot restoration. So, yesterday while working to get it to TDC for distributor installation, I found the battery dead once again. I put the charger on it and turned it on. Heard a crackle and looked inside the cab. Smoke was coming from the tape deck portion of the radio. I'm guessing it is toast and I haven't a clue why this happened. I need someone with some electrical expertise to tell me why the radio would get fried and also what would be causing the battery to drain power while the negative terminal is disconnected. I don;t know where to start diagnosing the problem. Any help would be much appreciated. Sure made short work of a $200 radio. I know it worked, too, as I had it on after I installed it and listened to some tunes while the battery was up.

I forgot to mention that the in-line fuses in the radio wiring are still intact and didn;t even blow.

I can think of no way the battery would discharge due to a external electricl drain while having only the positive post connected. I would suspect the battery.

I wonder if it is possible that the battery, the charger, or both have the polarity reversed. I have mistakenly hooked up a battery charger backwards before and charged a battery in the reverse polarity. This is easy to do with a charger that has color coded alligator clips that come off easily, comibned with a stone dead battery. This practice could lead to a battery not holding a charge, or you could just have a bad battery, even if it is new and charged correctly. The smoked tape player may be co-incidental, but I would double check polarity, and/or suspect the battery. A battery that goes dead with only one terminal connected, must be bad or have an internal short.

Rick:
Is it possible you didn't actually fry the radio, but maybe there was/is a short next to or behind the radio giving the appearance that the radio was smoking. I've also had batteries that just don't hold a charge, especially those that are not used for a few years.

One way the battery can discharge with the negative cable disconnected is for the battery hold-down to touch the negative terninal if it also is loose. This happened recently to someone on this forum. His actually touched both battery terminals.

It's possible the battery charger can put out too high a voltage if it isn't well connected to a battery, such as might happen if you just pushed the negative battery cable on without tightening it.

I believe your battery is bad & the charger voltage ran away with out the proper load.