20 Most Recent Sony STR-DB840 Receiver Questions & Answers


make sure sub is working .Power it up , remove sub RCA jacks from receiver .Gently tap on RCA with fingers.You should here a hum when touched .You can also try audio from TAPE REC OUT .If you dont get audio .Check setting at sub .If it working okay check setting at receiver and or sub level at receiver

Sony STR-DB840... | Answered on Dec 03, 2011


There are bad solder connections on the circuit board inside the receiver, if you are handy with a soldering iron remove the top part of the case and trace the center channel speaker wires to the board, this will isolate the problem in the general area, chances are it is the center channel ic that need to be retouched.

Sony STR-DB840... | Answered on Jun 18, 2011


That's for you to determine.

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Check for loose speaker connections at the speaker as a root cause for intermittent shutdown.

Sony STR-DB840... | Answered on May 23, 2011


There are 4 blue relays in the unit that has solder points that will crack over time.
It´s fairly "easy" to re-solder them and viola, it´s OK again.

open the cover (unscrew and take of the hood) and locate the 4 blue relays.0cddb82.jpg Unscrew and remove the bottom service plate and locate the soldering points for the 4 relays.c0f1d35.jpg
Each relay has 6 solderings, 4 in one "groop" and 2 in one "groop" look especially at the "2-groop" these are the ones most likely to crack over time ( for me 12 years or so).3436d08.jpge6f7344.jpg
Re- solder. Best of luck //Ronnie Stockholm

Sony STR-DB840... | Answered on Mar 06, 2011


SONY STR db840
No display:
broken trace on "Digital board" ,feeding 32v from "DC board" to "Display board"
solution: make new jumper btw. "CNS2" and "CNP4" on "Digital board"
Now display OK again : )

Sony STR-DB840... | Answered on Dec 28, 2010


Turn on the subwoofer output. There is a configuration option for all the speakers: left, center, right, surround, and sub.

Sony STR-DB840... | Answered on Jun 13, 2009


I am afraid not. That crackling is a component in one of the solid state amp circuits starting to fail. These are all soldered into the printed circuit board. This could be a difficult repair to find an intermittant component. Depending on how old the unit is and how much it cost will factor in on if you have it repaired or not. Rule of thumb is that if the unit is two to three years old and cost less the 200 to 300 bucks you should not invest more then 100 to 150 bucks into it. Good Luck

Sony STR-DB840... | Answered on Mar 16, 2007

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