PLEASE!! Still need help with an SAE Two A-14

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- rockinnomo
  
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posted
16 years ago

Fri, Apr 11, 2008 6:26 PM

I posted this a while back and am still needing help so here it is again. PLEASE E mail me directly snipped-for-privacy@verizon.net

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 snipped-for-privacy@verizon.net. Harvey

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- clifto
  
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posted
16 years ago

Fri, Apr 11, 2008 8:14 PM

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

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- Rheilly Phoull
  
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posted
16 years ago

Fri, Apr 11, 2008 11:09 PM

Phil has given you good advice.

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Cheers ............. Rheilly

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- Arfa Daily
  
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posted
16 years ago

Fri, Apr 11, 2008 11:53 PM

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