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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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I posted this a while back and am still needing help so here it is
again. PLEASE E mail me directly My electronics tech is having trouble fixing an SAE Two amplifier model A-14. It has no audio output. If he shorts across a relay the audio works fine. He has a good service manual but can't track down what the problem is. Does anyone know what the problem may be specifically? It was repaired for the same problem by another tech and the repair didn't last long. I do know that 4 ohm speakers are a no- no. He's testing with headphones. Sure would appreciate some help here. Please eMail me at . Harvey |
#2
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rockinnomo wrote:
I posted this a while back and am still needing help so here it is again. PLEASE E mail me directly Hell, no. This is a discussion newsgroup, not your personal slave crew. -- "Theoretically, there is nothing that can stop the government from taxing 100% of income so long as the people get benefits from the government commensurate with their income which is taxed." -- Barack Obama |
#3
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![]() "rockinnomo" wrote in message ... I posted this a while back and am still needing help so here it is again. PLEASE E mail me directly My electronics tech is having trouble fixing an SAE Two amplifier model A-14. It has no audio output. If he shorts across a relay the audio works fine. He has a good service manual but can't track down what the problem is. Does anyone know what the problem may be specifically? It was repaired for the same problem by another tech and the repair didn't last long. I do know that 4 ohm speakers are a no- no. He's testing with headphones. Sure would appreciate some help here. Please eMail me at . Harvey Phil has given you good advice. -- Cheers ............. Rheilly |
#4
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![]() "rockinnomo" wrote in message ... I posted this a while back and am still needing help so here it is again. PLEASE E mail me directly My electronics tech is having trouble fixing an SAE Two amplifier model A-14. It has no audio output. If he shorts across a relay the audio works fine. He has a good service manual but can't track down what the problem is. Does anyone know what the problem may be specifically? It was repaired for the same problem by another tech and the repair didn't last long. I do know that 4 ohm speakers are a no- no. He's testing with headphones. Sure would appreciate some help here. Please eMail me at . Harvey If there is no obvious problem, such as DC offset, that is causing the protect relay driver circuit to fail to drop in, and the amp is otherwise producing good audio, then this must actually be a very simple problem, that should not be any problem for an experienced engineer, armed with a full service manual, to track down. If your service tech is unable to do this, then I would have to suggest that he is not the right person to be looking at it. Assuming that it uses a TA7317 as the protect IC, then common problems are the timing cap for the switch-on delay, and the high(ish) value resistor that charges said cap. There is also usually a quite high value resistor between the relay coil, and the drive pin of the IC, and don't forget the relay coil itself. Rarely, the IC might be faulty. If your tech does not understand the inner workings of the 7317, he should download a spec sheet for it, where all will be revealed ... Arfa |
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