Sony Receiver STR - DA555ES Displays "protection fan" when turned on.

[Rick79]

Ok thanks. Im gonna try a new regulator and see what happens.

 

[Rick79]

I replaced the 3.3V regulator. The receiver is working, i can hear music from the radio, but i have a feeling some parts on the digital board are fried like you said because i noticed the sound shuts off when i select eq and other functions. The Regulator does get hot, but im not sure if its normal because after about an hour or so the fan still hasn't turned on. Is the fan supposed to be on constantly?

 

[KrisBlueNZ]

The regulator will be overheating because the damaged components on the digital board are drawing too much current. This is normal when a sensitive IC is damaged by overvoltage; it breaks down internally and draws a lot of current.

As far as I can tell, the fan is controlled directly by the thermistor that's attached to the heatsink with the output transistors on it. Its purpose is to keep that heatsink cool; the regulators are not supposed to get very hot.

 

[Rick79]

Guess I'll just keep it for parts

 

[KrisBlueNZ]

It has six nice audio amplifier stages which you could reuse. Four channels on the main board and two more on the rear amp board. It looks like they run from ±60V so they'll be able to deliver quite a bit of power!

So I would keep the power supply and power amps intact. Much of the rest of it will be dependent on the devices on the digital board, but there may be some more sections that you can salvage.

You're lucky that the full service manual is available. It would be a good place to start if you want to learn more about electronics and you can find an application for it. The outputs are specified for a 4Ω load so you could make a pretty powerful instrument amp (guitar, bass, keyboard etc) from two of them running in BTL (bridge-tied load) configuration. If you want an instrument amp, that is. It's just a suggestion.

 

[Rick79]

Cool. Thanks for the help and info Chris!

 

[Rick79]

It has six nice audio amplifier stages which you could reuse. Four channels on the main board and two more on the rear amp board. It looks like they run from ±60V so they'll be able to deliver quite a bit of power!

So I would keep the power supply and power amps intact. Much of the rest of it will be dependent on the devices on the digital board, but there may be some more secaions that you can salvage.

You're lucky that the full service manual is available. It would be a good place to start if you want to learn more about electronics and you can find an application for it. The outputs are specified for a 4Ω load so you could make a pretty powerful instrument amp (guitar, bass, keyboard etc) from two of them running in BTL (bridge-tied load) configuration. If you want an instrument amp, that is. It's just a suggestion.

Hello Chris
Not sure if you been busy but can you please help me with another receiver? I have a post in the electronic repair forum about the YAMAHA RX-V795a not turning on...

 

[KrisBlueNZ]

I've seen it. It's a little way down my list of Electronics Point posts to catch up on after the Xmas/New Year break.

 

[Rick79]

I've seen it. It's a little way down my list of Electronics Point posts to catch up on after the Xmas/New Year break.

Oh. So should i repost it?

 

[KrisBlueNZ]

Oh. So should i repost it?

No!