2621217005 for a Denon DRA-1025RA receiver
I am guessing the system IC is the microprocessor. Normally that is what it is.
Most microprocessors do not have the complete part number on the IC. A letter or two will be missing from the beginning and also from the end of the number on the IC. Many times technicians will be able to figure out what those missing numbers/letters should be, just from experience dealing with IC's like this. Many have common letters at the beginning like "UPD" or "UPC" for example.
That would be unfortunate if so. It is really hard to find old microprocessors, and they rarely make subs for them.
To be certain that the system IC is indeed the part that will fix the unit, can you tell me how you came to that conclusion.
I am about as close as you can come to being considered an expert on troubleshooting the microprocessor and I may be able to help you ensure that it is the part you really need. I have seen on many occasions when a technician replaces the micro and the unit still has the same problem. And I am talking about well trained technicians, not some dummy. It has happened to me on several occasions. The micro is a very hard component to troubleshoot with certainty. It could have a supply voltage missing, a shorted cap connected to it, an open resistor or a resistor that is just out of tolerance connected to it.
Is this IC a surface mount IC, or do the pins go thru the board?
Surface mount IC's are very difficult to replace, without excellent soldering skills you can damage the IC or leave solder bridges and without a high powered magnifier you can't see them.
since this is an old unit, it probably has an IC with the pins thru the board. In a dual inline package. Meaning that the IC is long and rectanglular with pins on both the long sides. Those are easy enough to replace with just decent soldering skills.
Many times with older equipment the micro can have the solder reflowed and it will fix the unit. After so many years, the solder will start to change in it's chemical make-up a little and not conduct very good. It gets heat stressed and you can tell because it will look a little "grainey" and not be nice and shiny.
All micros have a crystal that clocks the cycles of the micro, and you would need a O-scope to check it. Two of the 3 pins of the crystal go to the micro and have a sine wave at the proper frequency. You can also check the voltage on those pins and most measure at about 2.5 volts plus or minus a little. Ref #'s for a crystal start with an "X" like "X201" for example.
Since you must have the service manual for this unit (you have the Denon part number), you can check the schematic and find the crystal and see the frequency there.
I would like to tell you how to handle those emails, but I have never been an asker of questions and I am new here, so I don't really know the right answers on that issue. But I can say that you should only reject the solutions that you are sure are of no help to you. And when you decide to wrap things up on FixYa you should give a "FixYa" rating to the person who gave you the information that solved your problem, or if your problem can not be solved , the person who best helped you make that decison that the unit can not be repaired. Otherwise, Fixya will not give any of the "experts" the couple of dollars they are all trying to make for answering your question. You really should reject answers that just don't make sense to you.
In your case, you are getting some valid answers to where you can find that part, if available, and if you get the same answers from many different people, you should reward the first person who gave you that answer. But do not give a rating to anybody until you are sure you have finished using FixYa for this particular question. It is OK not to reject any answers, just make sure when you are finished, you give somebody credit for solving your problem, whether it results in you finding your part, or finding out you can not get it anywhere. I have yet to get credit for any of my answers on the premium solutions even though I have given people the correct answer, they just did not like the answer. But it doesn't change the fact that I was right about the problem they had. Sometimes the correct answer is not always something the person asking the question can use to fix the problem they are having. Mostly when it means they must take the unit to a repair center because the problem is not something that can be fixed by them. This is not to say that you can not fix this problem, I assume that you have some knowledge of electronics since you were able to get the correct part number that would only be listed in a service manual.
Give me a few hours and I will let you know if that part is available anywhere, in the mean time, lets make sure it really is the part you need. it may be something you will need to find on ebay or something from another one of these same unit's with a different problem.
I work with another Tech who has a saying "it's never the micro" and if you replace the micro and it doesn't fix it he says "at least you know what it isn't"
He is right more times than not.
Jun 25, 2008 |
Audio & Video Receivers