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.
Saturday, September 8th, 2018 AT 11:22 PM