Hello @Dr_PC_Repair,
The schematic for the Sony DA3000ES is available from https://www.hifiengine.com/
The Q1683 MOSFETs in your picture are part of a half-bridge digital driver. In many respects, they are similar to the motor driver I described in this article.
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Matching: IMO, this is not necessary as we dealing with a digital circuit not analog.
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Replace both: Recommend replacing both and potentially the HIP21011BZT. It’s been my experience that failure of any MOSFET will compromise the other and often the driver.
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Which MOSFET: Generally, the more capable MOSFET will work. We are dealing with a high frequency switcher where the MOSFET and it’s switching characteristic e.g. capacitance, speed, etc. However, deviation is not recommended. Given the devices mentioned in your original post, I would recommend selecting the device with similar gate capacitance and turn on/off times. This is generally safe if we assume conservative Sony engineers.
Be sure to verify pinout and inspect the thermal interface.
Happy soldering.
Sincerely,
Aaron