Led display goes dead

Sony has the user manual for the STR-DE635 here: https://docs.sony.com/release/STRDE635.PDF .

I hope this helps.

Cindy Wells

Maybe the Preamp driver IC, looks like a car audio ic on the main board.
Often with age the heat generated by the ic will destroy the solder.Makes it look like lava rock in bar-b-que grill. Which
causes an open circuit in the preamp driver to the audio power
stage.
Simply resolder them, most often restores audio. Should have
a bottom removalble cover.
If not, a fuse normally blows if ic or channel is shorted. Check if
display will say Power off, Protect, etc. That means there is a problem with a channel.
Most Sony receivers use darlington transistors, they short easily !!
I am an old school component level service tech, I think I do have a schematic for this model and many others.

I assume you mean the sony dosen't have a phono input? Then all you need is a Magnetic Cartridge Pre-amp. Your turntable plugs into this and the pre-amp goes into a spare aux on the Sony. Just do a search for the Pre-amp on google by putting in "Magnetic Cartridge Pre-amp".

Have you checked the rails to ground for shorts. Get hold of a variac as it does make things a lot easier.

Sound like you might have some shorted output devices.

Hope this helps
Thanks for using FixYa

first turn the actual volume up on that channel on the reciver then make sure your speaker wires in the rear are using the same lenght each

Nope, power supply it would not even power up.  The capacitors are fried

Maybe, it worked for me. my rear speakers workt ramdomly, often not. so i re solder the relay for the rear speakers, now it works fine everytime, a hole movie and some random on and offs, it can't do any harme to try=)

It may need soldering of the display, could also be a bad resistor or transistor in the power supply.

sorry my expertise is in appliances, youl need to repost you question to another tech

Turn your volume down,press the tape monitor button.then turn up?