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New member Username: MusicroverRosville, Ca Post Number: 7 Registered: Aug-06 | Hello, I am in need of an owners manual for a Sansui AU 717. Thank you. |
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New member Username: DevelaraTennesse, Ny Us Post Number: 2 Registered: Dec-06 | check classicsansui.com u may find one. dev |
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Silver Member Username: Arande2400dB could probably d..., 4000 isnt ev... 100,000dB FU... Post Number: 290 Registered: Dec-06 | He may be right... |
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Silver Member Username: Arande2400dB could probably d..., 4000 isnt ev... 100,000dB FU... Post Number: 292 Registered: Dec-06 | It's true...^^ |
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New member Username: HowlanPost Number: 1 Registered: Jan-07 | Hello All, I'm new and hope to get some help from anyone.here is what happen:I hook up AU-717 and other 150 WPC digital amp by speaker selector box(Monster Cable made)try to compare their performance by switching,it works fine if turn one off before turn another on. But disaster happen when forgot to turn first one off then both on at same time.digital amp remain okay but AU-717 is dead. I open the cover and found 4 each 7A /125V fuses are blown! Replace them with 7A/250V and blown again (4 fuses).I wonder the shortage happen on protector circuit or output transistors?where should I start with? Please help. Howlan |
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Bronze Member Username: DevelaraPost Number: 12 Registered: Dec-06 | hi howlan its very sad that u have blow a very good amp , any ways .......i think the problem is in the power section , there is a power board just before transformers check that out , hope u will find some good technician to service the equipment. dev. |
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Bronze Member Username: DevelaraPost Number: 13 Registered: Dec-06 | hi howlan its very sad that u have blow a very good amp , any ways .......i think the problem is in the power section , there is a power board just before transformers check that out , hope u will find some good technician to service the equipment. dev. |
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New member Username: HowlanPost Number: 2 Registered: Jan-07 | hi dev, thank you so much for giving me the clue.I have schematics on hand,hope I might be able to repair it under your supervision. howlan |
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Gold Member Username: NuckPost Number: 5669 Registered: Dec-04 | Howard, all of your output devices are blown. That may be all, but possibly the drivers are toast as well. Hit the electronics wholesaler nearest you. And don't do that again(I know you won't). |
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New member Username: HowlanPost Number: 3 Registered: Jan-07 | Hello Nuck,When you said driver refer to which parts? I will never do it again.But I'm just wonder the fuses should provide sufficient protection to the circuits or components.why took only half second will cause this much damages? |
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Gold Member Username: NuckPost Number: 5682 Registered: Dec-04 | H, the damage happens quick like a bunny. |
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Bronze Member Username: LeonskiPost Number: 21 Registered: Jan-07 | Sounds like the output devices are shorted. They are the ones bolted to the heatsink. In any event, take a smell. No kidding. When stuff fries, the smoke gets let out and it doesn't seem to work right, ever again. If you've ever fried some electronics, you know that odor. Did anything happen to the other amp? |
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New member Username: HowlanPost Number: 4 Registered: Jan-07 | Hi leo, I did try to smell but no luck.nothing happen to the other Amp.could have better ckt protection |
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New member Username: HowlanPost Number: 5 Registered: Jan-07 | Hello Dev, leo and nuck, I checked the power transistor(pull out from socket)2SA747 by ohm meter,they are not short and shows different ohmage on different pin. Turn power on with both channel power board unplug,no fuse blown!that narrows the problem to both channel's power board.good news at least. Howlan |
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Gold Member Username: NuckPost Number: 5790 Registered: Dec-04 | Howlan, please check the devices again, with your meter on diode check. If they all ring out the same, they could all be good OR bad. I will reach and say that you should ring on just one combination of the 3 available in each polarity. |
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New member Username: HowlanPost Number: 6 Registered: Jan-07 | Hi Nuck, diode checked are good, but don't know how to check zener diode. And found TR13(2SB537) emiter are short to collector(ground) on both channel board. Is this BINGO? thanks for your help. |
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Gold Member Username: NuckPost Number: 5792 Registered: Dec-04 | Maybe. Was the board fully disconnected(isolated) for the TR13 check? |
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New member Username: HowlanPost Number: 7 Registered: Jan-07 | Yes, desolder TR 13 and pull out from the board. |
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Gold Member Username: NuckPost Number: 5793 Registered: Dec-04 | howlan, is the TR a PNP or NPN configuration? It may be powered or switched under load. I cannot troubleshoot from here without a meter. Try this easy to use sight to determine the device. http://www.101science.com/transistor.htm |
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New member Username: HowlanPost Number: 8 Registered: Jan-07 | It's PNP |
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New member Username: HowlanPost Number: 9 Registered: Jan-07 | Nuck,this is a great website,wish have known this earlier. I went to the store 20 miles from home and bought 2 ea substitute of 2SB537, but they sold me NTE292!should be NTE153 instead.No wonder 4 fuses still blown after I replace NTE292 on it.but this time it hold for about 10 seconds before blown and NTE292 doesn't show shortage between E and B. I don't quite understand what does "switch under load" means? Thanks |
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Gold Member Username: NuckPost Number: 5799 Registered: Dec-04 | Depending on the function of the transistor, it will switch for different reasons. The E to B connection may be normally closed and switched on power up, or not. It may be switched at another time. Isolating the board will remove the earth from the board, so as to measure componants without the ground reference. As well, your testing seems to be going well, good for you! |
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New member Username: HowlanPost Number: 10 Registered: Jan-07 | Hi Nuck, My AU717 finaly alive! replaced TR12 and TR13 on both channels, cost me $19.69 now is working like a champ. Thanks a lot for your help. Howlan |