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Jeremy112
Joined: 28 Sep 2006
Posts: 2645
Location: Fond du Lac, WI
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 Link Posted: Sat Feb 14, 2015 1:27 am Post subject: Sony SAVA SA-VA55 IR Transmitter LEDs flickering/sound cuts |
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I've got a Sony SA-VA55 System in that has a seemingly simple issue. The rear speaker IR transmitter LEDs are half functioning. I took the cover off the transmitter, there are 5 rows of 4 IR LEDs, 2 of the rows aren't lit at all, 2 are, and one flickers in and out at random.
When the flickering row is not flickering and lit, the rear speakers work, when its flickering or not lit the rears get no signal at all.
Now it looks like most of the LEDs are a deep amber color, 3 or 4 of them still look clear yet. Would the LEDs be burned out? or is there something on the transmitter board that's going out?
Replacing the transmitter isn't an option since I've not found one yet. For the record the transmitter model is EMT-VA55.
If it is the LEDs, are there special IR LEDs? These ones I can see red light emitting from, not a lot, but just enough to notice they are on or not.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Link Posted: Sat Feb 14, 2015 3:31 am Post subject: |
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Jeremy112
Joined: 28 Sep 2006
Posts: 2645
Location: Fond du Lac, WI
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| Link Posted: Sat Feb 14, 2015 5:04 am Post subject: |
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Its the IR LEDs, I checked everything, the LED diodes that were bad are where voltage stopped passing through, easy enough to find, and I figured it was the LEDs since they look pretty used up. don't suppose you could point me to the right type of replacement LED since the part number in that schematic turned up nothing.
Thanks for providing that schematic, it helped a lot 
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macgyver655
Joined: 22 Aug 2007
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| Link Posted: Sat Feb 14, 2015 5:34 am Post subject: |
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You should be able to test each LED with your DMM on diode scale. They will read like a diode. Test each one because if 1 goes open the other in that series will not work. And because when you see how much they cost you will only want to consider replacing the bad ones.
But if you find any blown short then the series should of still worked so make sure those switching transistors are ok and all resistors.
The part number on the sheet is correct but that first letter that looks like a B is actually a D. There is a line there for whatever reason that makes it look like a B until you zoom in.
If you only have a couple bad LEDs you may be able to get 1 or 2 more rows working and the speakers may then work. You already know they work with 2 rows out. So if you can get 3 or 4 rows working you might be ok.
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Jeremy112
Joined: 28 Sep 2006
Posts: 2645
Location: Fond du Lac, WI
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| Link Posted: Sat Feb 14, 2015 5:39 am Post subject: |
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| macgyver655 wrote: | You should be able to test each LED with your DMM on diode scale. They will read like a diode. Test each one because if 1 goes open the other in that series will not work. And because when you see how much they cost you will only want to consider replacing the bad ones.
But if you find any blown short then the series should of still worked so make sure those switching transistors are ok and all resistors.
The part number on the sheet is correct but that first letter that looks like a B is actually a D. There is a line there for whatever reason that makes it look like a B until you zoom in.
If you only have a couple bad LEDs you may be able to get 1 or 2 more rows working and the speakers may then work. You already know they work with 2 rows out. So if you can get 3 or 4 rows working you might be ok. |
Yeah, I was able to pull the other 2 bad LEDs out and jump where they were, the rest all work, the other 2 rows must have went fairly early, they are quite bright. The system is working like it should though, I can walk in front of the transmitter without the signal dropping at all, so that's good.
I tried both B and D and I couldn't find an actual part or website that sells them. If I could find them I would probably order a few to have on hand because this is a friends system and they have no plans to get rid of it. Since some of the other LEDs that were still working are pretty dim I just want to be prepared if it happens again. Eventually if I keep jumping where the bad ones are, there wont be enough left to work anyway 
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macgyver655
Joined: 22 Aug 2007
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macgyver655
Joined: 22 Aug 2007
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| Link Posted: Sat Feb 14, 2015 3:42 pm Post subject: |
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| Jeremy112 wrote: | | Eventually if I keep jumping where the bad ones are, there wont be enough left to work anyway |
Also remember, every spot you jump then puts more voltage on the remaining leds in that series. This will cause premature failure.
You would be better off having 1 less row and the remaining rows have all working leds.
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