Denon x4200w - red light flashing assumed amp circuit failure


Active Member
My mate bought the above from RS in 2016 and took it back with him to Bahrain where it has been faultless.

This morning he’s fired it up and has the “red light flashing every 0.5 second” issue.
He’s unplugged everything (checking speaker wires for wiring crossover) yet still gets the same issue.

Any ideas at all please or is this a specialist repair?

If it is a specialist repair he’s gone be out of luck as no dealers in Bahrain and he can’t source a HiFi specialist anywayere.

Edit - Mate says there is only about 5/6cm air circulation at the top of the unit. IMO this can’t have helped.


Active Member
Hi there

Red light flashing every 0.5 second indicated on ASO/DC protection.You can confirm this, by following attached instructions and let me know what your amp shows as DC or ASO.



Active Member

Ah fantastic I’ve just forwarded this on to him to confirm.

About to jump on a flight so will update the post later on today.

Thanks again.


Active Member
Apologies I completely forgot about this!

Here is what’s happening:
“I’ve followed the steps, but protection kicks in as soon as I select the “2. Protection” option. The unit immediately switches off before the protection method is displayed, upon a restart the screen goes black after 6seconds”.

Have just uploaded a video to YT...



Active Member
Thanks for the video. I'm pretty sure one of the channels is faulty and sends DC volatge into speaker output.


Active Member
Nah, any electronic repair shop would be able to fix it for you. I deal with this type of fault all the time, but I'm based in N.Ireland.
Unfortunately my mate lives in Bahrain :(

Gawd knows what shipping would be to get it to you.


Novice Member
Hi there have the same issue with my denon x6400. Like ur video. I disconnected all my speakers connection but situation remains same. Red light blink every .5 sec cycle. I’m here in Bangladesh and hard to repair by any expert technician. It’s bought as brand new from Peter Tyson 2 months used now it turns to brick. My heart has broken. Can anybody plz suggest

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