Sony Receiver


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Old 04-01-04, 06:05 PM
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Sony Receiver

Hi all,
I have a complete sony home stero system and love it. Unfortunitely this will be the third time the receiver has broken. I hope you can help me figure out the problem. It is a model STR-D650Z. When I turn it on, protection begins flashing on the display. I toke into Bestbuy to have them diagnois and they told me it was a I/O Amp and would cost approx 160.00. This was going to be their thrid time repairing this unit and point blank dont trust them anymore. Long story short, does anyone have any suggestions? If so, I consider myself to be decent at soldering and would like to give this a try myself. Does anyone know what they might be talking about when they say an I/O Amp? Thanks in advance for any help in this matter.

Brian

Note: I did look for previous posts about this issue but I am sure I understood what was discusses. If possible, couls I sent someone a pic to help out?
 

Last edited by bculli05; 04-01-04 at 06:24 PM.
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Old 04-01-04, 09:50 PM
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doesn't best buy stand behind there work? there should a three month warranty on parts and labor. the I/O amp is new to me, it could be the final stage of your amplifier, or the pre-amp stage, or could bs. they can't fix it so they give mubo-jumbo to go to another shop for repair. I/O in computer terms is simply input/output devices connected to the computer. I don't know if this applies to your application, could be, amplifiers may be that sophisticted these days.
by all means don't try this repair yourself, you may make matters worse, and invalidate any warranties you have. Instead take it to an autherized sony repair shop, and also bring your speakers in, if the fault is in the speakers. for now that's all i can think of. good luck,snuffs
 
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Old 04-02-04, 04:23 AM
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age?

How old is this receiver?
Extended warranty?
What other problems did you have with it?
What are the symptoms?

If there isn't a Sony authorized shop nearby, you might try a small electronics repair shop to get a second opinion. But, if the repair is indeed going to be $160 or so, upgrade to a new receiver such as Onkyo.
 
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Old 04-02-04, 04:58 PM
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Unhappy Ideas???

Thanks for the replys unfortunitly the warr. is up (this also includes the extended warr.) Not to impressed with sony anymore. The next step is throwing it away so I'm not about to spend a another 160.00. The symtoms are, I turn it on, CD or what ever selection was on last comes on for about 2 seconds then begins flashing Protection. The receiver was purchased in 1999 so it is getting older. The receiver was used up until the night before. I went to turn it on the next morning and it began flashing protection. The links below sound very similar but I am not sure what how to check the final amp and other repair attempts. Could I send in a pic or someone explain what they are suggesting to do in teh attached links?


http://forum.doityourself.com/showth...t=sony+protect

http://forum.doityourself.com/search...by=&sortorder=
 
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Old 04-02-04, 05:45 PM
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Pics up to 10k can be attached to posts. If you need to post one larger than that, if you can host it, you can use a the vBcode to insert it in your post. Or, if you do not have a place to host it online, PM me for my e-mail address and I'll host it temporarily for you.
 
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Old 04-03-04, 04:04 PM
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A protection error is caused by shorted speaker terminals. Your amp is trying to drive a short which results in too much current being drawn.
this is an opion from another forum. i think it maybe a short from any channel output you have. did you say you found a 61 pin ic, mounted on vertical fins? this ic drives all the outputs, plus many more functions. is the resistor near this ic, and can it be tracked by an ohmeter from the resitor to ic? if so, the problem may be the ic. it may say STK on it. you should also look for shorts simialar to the one found. good luck, i can't provide a schematic for it. I guess your trying your luck, not much to lose if your going to junk it. Mat electrtonics can give price and availbilty quotes.
snuffs
 
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Old 04-03-04, 06:05 PM
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This "Protection" fault is a common condition with Sony receivers of this time period. I had TWO Sony receivers with this problem. I am an engineer at a TV station, and I was uwilling to get the proper schematics and parts to fix the problem, because of $$$. I have heard of many other Sony's with these same symptoms.
Buy a Pioneer, and relax
Good Luck!
 
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Old 04-03-04, 06:23 PM
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The term I/O is a general one and stands for Input/Ouput - not just for computers but any piece of equipment - even ICs. We quite often refer to the pins of ICs as I/O pins. The other kinds of pins on an IC can be Power, Ground and no-connects(NC).

Never heard of an I/O amp. Just like snuffs suggested the protection error suggests an overload at the ouput. This can be caused by shorting the output lines of the amp to the speakers. If the fault is internal it could be caused by a number of things.

Most amps use two output transistors configured in class A-B operation. If one or both transistors develop a short across the emitter-collector junction you can get an overload. Other possibilites include faults with the bias circuits of one of the driver stages earlier in the amplifier circuitry or a shorted cap in the zobel networks (if they do have Zobels on this unit).

If it an STK type IC all the transistors are integrated within so you cannot chage individual transistors and will have to replace the whole unit.

A short on the circuit board between 2 pads is also a possibility.

Unless you can get a good answer out of the people doing the repair you may be better off looking at buying a new unit.
 
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Old 04-05-04, 09:40 PM
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Did you try running the receiver with the speakers turned off to see if you get the same problem? Check if there isn't some terminals shorting against others inside the unit. Some of those hand-soldered connections can be questionable.

In my experience, Sony makes very decent equipment as long as you stick with their ES-series components. Unfortunately for us, the consumer-grade non-ES designs are purely price-driven and has been so cost-reduced that they suffer in reliability and robustness.

The non-ES amps tend to be weak and current-limited when trying to drive low impedance speakers. Their amps are typically rated for nothing less than 8 ohms. There's a 'low-impedence' switch to run 6ohm loads--that smells like a kludge since "the big" amps drive all the way down to 2ohms without problems. :-)
 
  #10  
Old 04-07-04, 07:56 PM
m_adkins
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My Sony just did the same thing. Apparently, they are prone to this type of failure. If the unit does not work with the speakers disconnected, its toast. The parts are not expensive, but the labor is. I've heard figures of about $170 if you can find someone to repair it.

For myself, I'm buying a new unit.
 
 

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