The owner was moving a speaker with it on and a wire fell off and a loud 'pop' sound. I figured a power amp channel got damaged.
Just to let people know, if you run these with the back panel off, there is a missing ground connection and the receiver does not work. The display stays off and standby led goes flashing, like it's stuck in Protect mode.
I temporarily added a jumper from a top HDMI PCB RCA jack to the lower cards, checked ground continuity and the stupid receiver seems to work fine now
Missing that ground (because it's apart on the bench) , pressing ON button relay RL901 powers up the amplifiers to 1/2 voltage at +/-28VDC and after two seconds it shuts off and the standby LED flashes. If you press and hold any button, it keeps +/-28VDC power on. After the two seconds, if things are OK it is supposed to switch on two additional relays to kick up amplifier power high to +/-55VDC.
I had tested every power amp transistor and fusible resistors etc. and all test fine. I had checked each amplifier channel output stays at 0V, there is no DC offset. VPROTECT and IPROTECT bus stays low 0V. VOLH is also low.
So I'm not sure why the original complaint of some display error message went away. I'm re-assembling it and we'll see if it works.
Just to let people know, if you run these with the back panel off, there is a missing ground connection and the receiver does not work. The display stays off and standby led goes flashing, like it's stuck in Protect mode.
I temporarily added a jumper from a top HDMI PCB RCA jack to the lower cards, checked ground continuity and the stupid receiver seems to work fine now
Missing that ground (because it's apart on the bench) , pressing ON button relay RL901 powers up the amplifiers to 1/2 voltage at +/-28VDC and after two seconds it shuts off and the standby LED flashes. If you press and hold any button, it keeps +/-28VDC power on. After the two seconds, if things are OK it is supposed to switch on two additional relays to kick up amplifier power high to +/-55VDC.
I had tested every power amp transistor and fusible resistors etc. and all test fine. I had checked each amplifier channel output stays at 0V, there is no DC offset. VPROTECT and IPROTECT bus stays low 0V. VOLH is also low.
So I'm not sure why the original complaint of some display error message went away. I'm re-assembling it and we'll see if it works.
. Mine unit was constantly switching on/off without the back panel.
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