Radio not working after battery change

Check your owners manual. It may require a security code input after losing power.

You never stated if it was a factory radio or not so I mentioned the security code. All you can do is verify all the fuses are good. If they are good, then the problem is internal to the radio and then looking at an aftermarket replacement would be the best idea.

The radio broke down a long time ago, but the problem will not show up until memory power is removed as in replacing the battery. If you have the cassette model 56038518 or the CD model that ends with "67", these are built by Chrysler with a microprocessor built by North American Philips, (NAP), the same people who build the really crappy Magnavox and Philips tvs. All microprocessors in all electronic equipment have a "reset" circuit that sets the millions of transistors to their starting point, (on or off), rather than letting them start from some jumbled random state. That reset circuit only operates for a few milliseconds when power is first applied. After that, its job is done and it will not operate again until the next time the radio is unplugged, the battery is disconnected or run dead, or the interior lights fuse is replaced. That fuse is the memory circuit for the radio. Once the radio is up and running, that reset circuit can fail and you will never know it.

The most common problem is the three yellow leds in the tone controls blink about once per second and you hear a thump in the speakers at the same time. There is a list of about a dozen other things that go wrong, all related to the microprocessor. Some radios go out for five seconds after moving the volume control. On some the sound will quit when you move a tone control and will not come back until you turn the radio off and back on. Sometimes the stations will not change when you try to tune to a new one. This mostly affects the radios with the three lighted tone controls but there are some models with two non-lighted tone controls that are also affected.

A lot of mechanics are falsely accused of damaging these radios because the problem shows up right after they performed any service that requires the battery to be disconnected.

There are two models built by Mitsubishi that are direct replacements and are real high quality. They look the same, mount the same, have the same lighted tone controls, and will run the same remote cd changer if you have one. The cassette model has one extra button for "scan". These radios weigh about three times more than the Chrysler-built models. They were only used for one year in only a few car models so they are kind of hard to find. They are in demand by used car dealers to replace non-working radios in their cars. I have some of all three, the cassette model, CD model, and the combo units.

Caradiodoc

You missed the point of my entire story, or I did not explain it well enough. The reset circuit is not a safety or anti-theft circuit as we are used to talking about. All microprocessors, whether in a laptop, a microwave oven, or a cell phone have millions of transistors in them. When power is applied, it is anyone's guess which ones will turn on or off and turn others on or off. With all of them in random states, there is no way the unit could work properly. Every transistor has to be set to its starting point as designed, then it starts to do stuff from there. The purpose of the reset circuit is to turn on just those transistors that must be on, and to insure those that must be off are indeed off. That entire process takes just a few microseconds, then that reset circuit will not operate again until the next time power is applied. Reset circuits are built into the microprocessor as part of those millions of transistors. There will be a dedicated reset circuit outside the microprocessor, but that is just to tell it it is time to power up and do its thing.

The key fact is you need and must have a working reset circuit. It is not something that can be bypassed, and you would not want to as that would render the unit not able to work.

As a related side note, there was a radio model that used transistors for this job that were rated at only 10 milliamps, which is way too small for this job, but since the whole ordeal is over so quickly, there was not nearly enough time for those transistors to overheat. They could hold up to the task, and the engineers knew that. That is, until some bad solder connections developed inside the radio. The radio continued to play fine, without any symptoms, but every time the car went over a bump, it caused those connections to work just long enough for the reset circuit to activate again and again, over and over. Each time a little more heat was generated in the transistors until they could not take it any more, and they exploded. When the ignition switch was turned off, then back on later, the reset circuit was dead, and so was the radio. That repair involved replacing two transistors, but it was difficult to find replacements so puny. Any transistor that is rated for more current will work. I used some rated for a full one amp that cost about twenty cents each.

The point of that sad story is imagine if that part of the reset circuit is inside the microprocessor IC. That is a sealed block of epoxy with everything inside. You know if there are millions of transistors in a one-inch square part, there is no one alive with good enough eyesight to peel it apart, find the defective part, and replace it. The microprocessor is junk. In fact, I marvel that with hundreds of millions of products sold, more of them do not break down. Anything with a digital display has at least one microprocessor in it. New flat-screen TV's will have four or five dozen of them, and they are surprisingly reliable. There can be dozens of computers on even 1990's model cars, and each of them has multiple microprocessors in them. In my lines of work, (TV/VCR repair, and car repair), all I see over and over every day are things that are broken. I do not get to see the other ninety nine percent that are working fine, so it is that one percent that makes me nervous about owning a four year-old truck.

To get back to your radio, the repair involves replacing the microprocessor IC. I have the hot-air soldering station for doing that, but even if I were to buy the part and install it, software has to be "burned in" specific to that model. With the wrong software, it could try to run a CD player when it is in a radio with a cassette player. The equipment for doing that is very expensive, it would be obsolete in short order, and I could never do enough repairs to cover the cost. The far better alternative is to just find the Mitsubishi-built radio that replaces yours. It looks the same, but with one extra push button, it runs the same four-disc CD changer, it mounts the same, and all the other controls are the same. The only other difference is it weighs about three times as much as your old one. To my knowledge, that cassette model was only used in 1999 Neon's. For a number of years when a cassette radio brought ten buck on eBay if you were lucky, these were going for over $70.00 because all the used car lots in the country were looking for them for their trade-in cars. Today they should be easier to find at salvage yards because the cars the radios went into are in the yards now.

I actually sold one of these replacements a few months ago. It was the last one on my display board that I take to an old car show swap meet. I might have a few left if I look hard enough, but you should be able to find something at a local salvage yard. There was the cassette version, a CD version, and a few years later there was a CD/cassette combo available. Look for the same two plugs, one black and one gray, and if you have the four-disc CD changer, the radio must have the same 8-pin round black plug for that cable.

In the earlier years the radios had face plates with square corners. Those would work in your van but they will not mount properly. You need one with the rounded corners. Those mount with one screw in each corner. 1999 to 2003 was the period when they were switching over, and both versions were used in different car models. If you get too new, as in around 2002 radios, those use a different single connector. Those will not work without making an adapter harness. That is way too much work when all you need is the right radio that just plugs in.

I used to have all these radio model numbers memorized. If you cannot find the right radio, let me know and I will find the number you need. Do not accept one with the same model number you have now because you will just have the same problem in the future. I am really surprised yours lasted this long. They all broke down a long time ago, and a lot of mechanics got unfairly accused of causing the problem when they had to disconnect the battery to do some other repair work on the car.

All Mitsubishi-built radios have a "Supplier # 28046" on the model number sticker. That is the ones you want to look for. I am embarrassed to admit after all these years I cannot remember the supplier number for Chrysler-built radios. They also had some built by Alpine with Supplier number 26777. Those are good ones to stay away from. Alpine will not allow any repair centers to sell parts or service manuals for their OEM radios.