I have a sony STR-DA3000ES. It is old - but barely used. Very early on soon after I purchased it, I received a Protect Error 22 on it. It has been in my closet since then. I have scanned the internet - the recommendations all deal with removing the speakers. I have removed all speakers and still get the error code.
I tried to check all output transistors while on the PCB - and they all look the same related to resistance between the pins. Hard to really know if they are good or bad as I have not removed them from the PCB. But the ohms are consistent across the different transistors - so my guess is they are OK (or all bad). One think that I cannot create - put a positive voltage on the gate with ohm meter to turn it on; and then I don't get low resistance when I measure drain to source resistance on any of them. I suspect that may be because they are still mounted in the PCB.
The service manual says Protect 22 : "Two defects a e considered, when current detection of a switching power supply operated by the super fluous speaker, +B power supply shut down or when the power MOS broke and +B line short. Turn off the receiver and check the speaker connection. Then turn on the power again?"
There have been some service bulletins to check on some specific cold solder joints - which I have visually inspected and also checked with ohm meter. They appear OK.
Any ideas on how to narrow the problem?
I tried to check all output transistors while on the PCB - and they all look the same related to resistance between the pins. Hard to really know if they are good or bad as I have not removed them from the PCB. But the ohms are consistent across the different transistors - so my guess is they are OK (or all bad). One think that I cannot create - put a positive voltage on the gate with ohm meter to turn it on; and then I don't get low resistance when I measure drain to source resistance on any of them. I suspect that may be because they are still mounted in the PCB.
The service manual says Protect 22 : "Two defects a e considered, when current detection of a switching power supply operated by the super fluous speaker, +B power supply shut down or when the power MOS broke and +B line short. Turn off the receiver and check the speaker connection. Then turn on the power again?"
There have been some service bulletins to check on some specific cold solder joints - which I have visually inspected and also checked with ohm meter. They appear OK.
Any ideas on how to narrow the problem?
One other observation - when I power up, display shows "Headphone" - so it thinks I have headphones attached. But I don't.
It appears the +12V/-9V line going to the D-Amp in CN-1852 is the problem area. When I disconnect this line - it doesn't go into protect mode; still shows "headphone". Wondering if the circuitry around the headphone amp is the problem? Maybe telling system that headphones are connected?