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I have a Technics SA-GX470. It displays the last selected input and then overload turn power off. The owner admitted running the volume pretty high and it would go into overload and after power off and on it would clear and he apparently did this a lot. I suspect the overload relay or the Audio power module. I need the schematic at this point. A service manual costs over half what I feel it is worth at this point. Any help would be appreciated.

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  • Ronald Williamson Nov 18, 2008

    Found PDF copies of the Manual all over the net. Found a couple close to this Unit but not close enough at this point. PDF copies when it comes to the schematics are hard to read sometimes. I finally called Panasonic and they had the actual Service Manual in Stock for $6 and $3.45 shipping. This is cheapest route right by getting the right manual to make sure if all the power supplies are OK before investing in the expensive Driver Modules. If I was in Hong Kong I could pick up one for $10 but I am not there and here in the states they are $50-70 depending on who you order from. They are made by several companies but most are discontinued or on back order. Panasonic does have them and the proper ones for Technics Units. The owner says to junk it but I figure for the price of the manual I can still tinker. I am retired and like challenges. Will keep posting.

  • Ronald Williamson Nov 20, 2008

    Well, I have gotten the original manual from Panasonic for $6, shipping $3. I believe the problem is the RSN3306 Power Module for the front speakers. It a little expensive and the owner does not want to spend the money. I am going to look around locally to see if a shop here has one. I can buy a working unit for $50 but the part runs about $60 from Panasonic. If it was about $20 to $30 I would buy the module. Other wise these prices cause a lot of electronics to hit the dumps. That's what happens to many TV's unless they can get a sap like me to fix it for nothing. With economy like it is and stores with warehouse full of Flat Screen TV's the prices are dropping. I was at Bestbuy today talking to a sales person and he said sales on big ticket stuff was miserable.. They are very worried. Checked your 401K lately. They are not only taking what they have given but what you gave too. I will keep you informed.

  • Ronald Williamson Nov 30, 2008

    Concerning SA-GX470 Technics. I got the original service manual and have determined the main power out module is bad. Due to cost owner says to junk it. Anyway if someone has a inexpensive source for these Hybrids, let me know. I also would like to know why Panasonic has to make their so complicated.

  • Anonymous Apr 28, 2009

    I can't find an owner's manual anywhere. Don't need schematics, just want to know how to use it. Not worth paying for though. Oh well

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I have not solved it yet. I did find a similar schematic of another model. I have gone over the entire board checking connections first. What I see is the minus 14 volt regular running very hot. The voltage is OK but there is something drawing a lot of current. The plus side is cool. I am in the process of looking at all the loads on it but believe it may be the main power module. This unit has two modules with the main one for the left and right speakers and another that is for the center and surround speakers. It is cool and guess the the main one may be bad. Panasonic is the only source for this one and that is doubtful. The prices I have found is around $60 and a little expensive to buy and just try. I am going to make sure it is the problem before I recommend they spend that much up front. Technics is a low end Panasonic product and I have found this to be a very troublesome unit as well as others. It's design is complicated as all Panasonic products are. I worked on this unit several years ago and the same problem went away. I suspect one of the output transistors in the module has gone rendering the whole thing bad. Whatever happened to a simple transistor replacement. I will keep you informed.

Posted on Nov 15, 2008

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