Sony AV receiver sometimes only right channel working... - Page 1
Forum section: electronics / repair

author: darkyputz
author_rank: Newbie
timestamp: July 16, 2015, 01:28:47 am
content: Hello friends of the short circuit...I have a sony av receiver that works pretty well...but since a while, the left channel likes to mute out...Turning it louder or hitting against the receiver is solving the problem soemtimes for the rest of the day or just a fewseconds before it starts again...Any Idea what taht could be or how to find the bad part?Thx in advance...

author: KG7AMV
author_rank: Frequent Contributor
timestamp: July 16, 2015, 01:46:41 am
content: Bad Solder Connection?

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: July 16, 2015, 02:00:20 am
content: Hi,I recall the same issue with a Sony AV amp, but cannot recall the model number. Had a similar problem with a Kenwood that I still use. Both were down to dry joints.If you haven't looked at an issue like this before (apologies if this is an insult...)- use a plastic prod to press around the PCB (s) whilst the unit is on and working. Have a good look with a STRONG magnifying lens; best to remove the whole PCB for this- daylight is best because of the reflections from the solder joints. It takes longer than you would imagine to check all joints on a PCB so patience is the thing. Obviously if you have a scope then a stereo amp repair is a doddle- find where the signal disappears on one channel but not the other. Don't forget to check any speaker protection relays, and the output and input switching. A damp finger introducing hum can be an easy technique, but make sure that the mains only goes to the transformer primary. Some amps have 50V-0-50V PSUs so can bite.BT

author: tec5c
author_rank: Frequent Contributor
timestamp: July 16, 2015, 09:03:09 am
content: +1 for dry joints.Some Sony models have a panel on the bottom that allows for ease of access to work on, though I can't recall which models these are. Otherwise, gain access to the bottom of the main board and start inspecting the solder joints of the output transistors and associated circuitry.

author: radioFlash
author_rank: Regular Contributor
timestamp: July 17, 2015, 12:24:27 am
content: I had a Sony receiver from the mid 90's with intermittent power issues. It turned out to be a broken solder joint around the power transformer. In my model, the transformer was soldered to the PCB, so a little movement, and you had broken joints. I found it by tapping around with a non-conductive stick.

author: darkyputz
author_rank: Newbie
timestamp: July 18, 2015, 01:47:35 pm
content: Broken joint sounds promissing...cause when i turn volume up to max or tab the device sound returns...Which could also be a capazitator i think, but i will inspect my jammy for joints...firstThx so far...If any one has additional ideas...I am open to all

author: David_AVD
author_rank: Super Contributor
timestamp: July 18, 2015, 11:27:35 pm
content: First thing to check with intermittent issues like that is cracked solder joints.Older gear can also suffer from oxidisation on the connector pins, so cleaning each half with a small squirt of contact cleaner can help.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 28, 2015, 03:29:20 am
content: would be nice to know the model ? i have repaired quite a lot in the past.Bad solder, cold joint where very common .... take your time to check evrything.