Yamaha STR-7065 - HELP No FM

daveyh

AK Subscriber
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I am working on a Sony STR-7065 receiver that I just rebuilt the output board on and I am getting great reception and signal strength in AM, but NO FM stations. It shows signal strength on the meters but there is only a white noise that comes from the speakers. I have a powered antenna hooked to it but it still does not make a difference. Anyone know where I should be looking??
 
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Do you have a block diagram or schematic of he reciever section?
 
I am working on a Sony STR-7065 receiver that I just rebuilt the output board on and I am getting great reception and signal strength in AM, but NO FM stations. It shows signal strength on the meters but there is only a white noise that comes from the speakers. I have a powered antenna hooked to it but it still does not make a difference. Anyone know where I should be looking??

Does it indicate stereo FM ?
 
Need to check to see if and audio signal is present on pins 11 & 12 of IC301. Scope would be handy...
 
Need to check to see if and audio signal is present on pins 11 & 12 of IC301. Scope would be handy...

Anyway to check it without a scope? I have one sitting here but I need to get some probes.

I did notice that the FM light stays on all the time when in the FM mode and there is small amount of static in the right channel in FM and the AM mode.
 
Going out on a limb here..With a multimeter probe those two pins with the meter in the lowest AC range. With the FM tuner tuned to the strongest signal to see if you have a very small "probably less than a volt "fluctuating AC voltage. I'm thinking the IC chip is toast .
 
Going out on a limb here..With a multimeter probe those two pins with the meter in the lowest AC range. With the FM tuner tuned to the strongest signal to see if you have a very small "probably less than a volt "fluctuating AC voltage. I'm thinking the IC chip is toast .

OK. I will try that. It makes sense. The FM meter light is fluctuating voltage.

If it is this IC, do you know where a person can acquire one at a reasonable cost?
 
Going out on a limb here..With a multimeter probe those two pins with the meter in the lowest AC range. With the FM tuner tuned to the strongest signal to see if you have a very small "probably less than a volt "fluctuating AC voltage. I'm thinking the IC chip is toast .

I set the meter on the lowest range and probed the pins and I get 4.2v Don't know what it should be.
 
I set the meter on the lowest range and probed the pins and I get 4.2v Don't know what it should be.

Neither do I, but that is probably the "white noise" or hiss that your hearing.Really need to look at it with a scope.
 
Neither do I, but that is probably the "white noise" or hiss that your hearing.Really need to look at it with a scope.

Ok. I may be looking at the wrong IC. Can you perhaps tell me the correct cross reference number for the HA1156. It has different numbers for this Sony board. Your post refers to HA1156 is on IC301 but some cross references say IC201 Sony CX-0412. I was looking for a source and some refer to Sony CX-0412 as being the replacement for the HA1156?? I just needed to clarify so I can make sure I am looking and probing the correct one.
 
Ok. I may be looking at the wrong IC. Can you perhaps tell me the correct cross reference number for the HA1156. It has different numbers for this Sony board. Your post refers to HA1156 is on IC301 but some cross references say IC201 Sony CX-0412. I was looking for a source and some refer to Sony CX-0412 as being the replacement for the HA1156?? I just needed to clarify so I can make sure I am looking and probing the correct one.

Do you see IC301 silkscreened on the circuit board ? If so, what is the part number on the chip?
 
I found it. Under the tuner. I could hardly read it because the screen had almost come off.

The chip reads:

SONY 043
3F 007
 
I was looking at a service manual for a Sony STR-7065A and it does have a HA-1165 chip. My receiver is a Sony STR-7065 without the A. I don't know the difference between the two receivers but the boards are different. Maybe a newer model?
 
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