EV7200 Amplifier - Shuts Down

[michalk3777@gmail.com]

Hello,
Not much experience repairing audio equipment.
This was working and stopped when disconnected and moved to a different location.
When power is turned on, the ON LED and both Protect LEDs come on, but within about 1 sec. you can hear a relay click and both Protect LEDs turn off.

There is a visibly overheated resistor R65 with the paint flaked off, that is supposed to be 1.5KOhm, it still measures 1.5KOhm. I also checked temp of that resistor with thermal cam. its about 140C.
So far checked incoming voltage and board voltage. Both DC output and AC output are present all the time after powering on. AC=48V; DC= 129V.
Would like some direction what to check next.

Attaching pictures and manual with wiring diagram from ElectroTanya.

Any help would be much appreciated.

[petehall347]

Re: EV7200 Amplifier - Shuts Down

check the line voltage first ..
then remove d16 and check it .

[eccerr0r]

Re: EV7200 Amplifier - Shuts Down

R65 should be roasting normally... poor design but that's what it is... but if it breaks you won't get any sound out.

If D16 shorts, would the relay even click?

the relay should click the speakers off during weird situations like overpower or even rapid start up of one of the rails. this is an interesting design that it actually seems to protect both up and down transitions (unlike some of my amps they only protect one transition).

From what i'm seeing this almost seems normal operation, is the problem that there's no music coming out? Testing with speakers right at the output or have really long wires to the speaker that could be suspect?

(as an aside, is that bridge rectifier on that schematic drawn right? Maybe I'm just not used to seeing all the diodes drawn out...)