Home |
Search |
Today's Posts |
|
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. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
SAE Two amplifier model A-14...no audio output. Help?
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
Posted to sci.electronics.repair
|
|||
|
|||
SAE Two amplifier model A-14...no audio output. Help?
On 3ÔÂ27ÈÕ, ÉÏÎç4ʱ01·Ö, rockinnomo wrote:
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 Do you want access to China's massive pool of electronic manufacturers... but lack the time to contact suppliers, negotiate contracts, arrange shipping or monitor product quality? Don't worry - Let seriouswholesale deal with all that for you. *Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD / Audio, and Computer Accessories now by visiting the online wholesale catalog at seriouswholesale. com You'll have peace of mind thanks to the seriouswholesale Quality Control, 12-month Warranty on all products, and easy secure payment by credit card through Paypal. Selling on eBay or your own online store? Send products direct from our warehouse to your customers using our unique drop-shipping service. You can profit by selling hundreds of different products, without holding any of your own inventory! Any questions you have will be answered by the seriouswholesale English-speaking customer support team... Their aim is to make your China electronics importing business easier to run than ever before. Welcome to http://www.seriouswholesale.com. seriouswholesale - Buy from the source, profit without the hassle. - 12 Months Warranty - No minimum order restrictions - Drop-shipping with no additional fee - Pay by safely by PayPal seriouswholesale Wholesale Co., Ltd.: Chinas original and best online electronics wholesaler & drop-shipper: seriouswholesale. com |
#3
Posted to sci.electronics.repair
|
|||
|
|||
SAE Two amplifier model A-14...no audio output. Help?
"greenpjs" wrote in message ... On Wed, 26 Mar 2008 13:01:29 -0700 (PDT), rockinnomo wrote: 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 I had one of those years ago that did the exact same thing. The first time, it was the relay itself. The contacts were corroded. I replaced the relay which fixed the problem for a few months. Then whatever drives the relay went out. I ended up just bypassing the relay with intentional solder bridges and using it like that for another few years. The only thing the relay does is avoid a minor "thump" on power-up so it isn't really needed if the amp is operating normally otherwise. ...Pat I'm sorry, but that is absolutely *not* the most important reason for the relay. Whilst there is a delay in activating it to avoid the switch on thump that would otherwise ensue as a result of the output stage supply rails stabilzing, its much more important function is to disconnect the speakers from the output stages in the event of a fault developing which causes there to be a DC offset at the midpoint. If this is allowed to find its way to the output terminals, the result will likely be a destroyed speaker cabinet. So, whilst bridging the (non active) relay will cure a lack of output, assuming that it is not failing to close because its control circuit *is* actually detecting a fault, you will have lost any future insurance against speaker damage, if an output fault should occur ... Arfa |
#4
Posted to sci.electronics.repair
|
|||
|
|||
SAE Two amplifier model A-14...no audio output. Help?
rockinnomo wrote:
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 Hello Harvey, While I don't know this amp in specific, see if it uses the TA7317 protection IC. It's a great IC and was used by many manufacturers. I've seen the electrolytic capacitors around the IC cause problems, as well has high value (150K or 220K as I recall) resistors go off value. The IC itself rarely fails. I would not suggest bypassing the relay. Regards, Tim Schwartz Bristol Electronics |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Marantz Audio Amplifier Model 1030 , Noise problem (audio inside) . | Electronics Repair | |||
Pioneer car CD player model:DEH-46DH need audio output IC # | Electronics Repair | |||
Bose 7 channel car amp model:143158 no audio output | Electronics Repair | |||
Tivoli Audio Model One - output amplifier or diagram | Electronics Repair | |||
Vintage R12R Ampeg - guitar amplifier - lack of audio output gain - need help | Electronics Repair |