Chuck awker
Active Member
My amp stays on even when power turned off.Must be in the protection circuit, maybe.Red power light on always.
Any idea?
Any idea?
AU717 power stays on
- Thread starter Chuck awker
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I'd more suspect the power switch has the internal contacts fused shut from arcing, or the actuator is broken and not moving the contacts when cycled. Out of curiosity, when the switch is in the off position, is the red LED solid or flashing (indicative of the protect circuit being active)?
Chuck awker
Active Member
Light is on always,not blinking whether switch is on or off,but
I have it on a power strip so when I turn on strip the protect circuit does its blinking,for the usual few seconds then light stays on.This is still when power switch on amp is still off.
I have it on a power strip so when I turn on strip the protect circuit does its blinking,for the usual few seconds then light stays on.This is still when power switch on amp is still off.
Ok. Does the switch feel normal (with a crisp detent action between off and on)? Or does it feel soft/mushy as if something is wrong internally? I have to think it's the switch. The protect circuit would not keep it operational when powdered off, in any case.
Chuck awker
Active Member
Yes,it feels like it always did.You know it's on and off,no mush.
Chuck awker
Active Member
Just started doing this today.Had the amp for 7 or 8 years.
Chuck awker
Active Member
I just looked at the amp and the power light was on so I thought I left it on but no,it was still in the off position.
You can try a multimeter set to continuity check to check the power switch (unplug the amp first!!!). The wires connecting to the switch are usually insulated and might be tricky to probe. You can instead check for continuity at the back of the amp where the accessory outlets are. The top outlet is switched and the bottom two are unswitched. Check for continuity between the two points circled in red below. You could also check it without even opening the amp by partly inserting plugs into the two outlets and probing the corresponding blades. Again, do this all with the amp unplugged!
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Alex22
Well-Known Member
The switch may have fused internally like others have said. It does take an inrush of power when turned on that could eventually damaged the switch.
You will have to investigate the switch or get someone to do it for you, to make sure for example that the switch is not taking a larger inrush of power than is normal.
I have been considering changing C604 on the power supply and protection board on my 517 to a higher value (330uf on the 515 and 470uf on the 717 originally) this can get rid of a small pop heard on startup but may result in a larger inrush of power than normal which would put more pressure on the switch. It could be that you have a bad capacitor in this area that overloaded the switch, just a possibility.
Any way I would find out the source of the problem (could well be only a failing switch) and repair/replace the switch. It is a beautiful amplifier and may not be worth risking further damage by not doing a timely repair.
You will have to investigate the switch or get someone to do it for you, to make sure for example that the switch is not taking a larger inrush of power than is normal.
I have been considering changing C604 on the power supply and protection board on my 517 to a higher value (330uf on the 515 and 470uf on the 717 originally) this can get rid of a small pop heard on startup but may result in a larger inrush of power than normal which would put more pressure on the switch. It could be that you have a bad capacitor in this area that overloaded the switch, just a possibility.
Any way I would find out the source of the problem (could well be only a failing switch) and repair/replace the switch. It is a beautiful amplifier and may not be worth risking further damage by not doing a timely repair.
I’d still want to be 100% sure the switch was the issue. I recently worked on an AU-717 international version (XX) that had a broken terminal strip on the rear panel by the cord inlet. Half of it had come free from the rear panel and was dangling by the connected wires. The loose wires could have have easily shorted to the chassis and caused a shock hazard.
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BTW in case it is indeed the switch that’s broken, there’s a switch from an AU-719 on eBay at the moment. I’d bet it’s the same switch as the AU-717.
https://www.ebay.com/itm/295220094090
https://www.ebay.com/itm/295220094090
Chuck awker
Active Member
Ok folks,I think I found the problem.
So,about a year ago I was transferring unit,stupidly,trying not to un hook anything in back.Sadly it dumped behind cabinet.It fell only a couple feet but pressed in the top ac plug all the way where it is basically just hanging in the case but still next to hole.
So when orv00 wad talking about continuity and such I was about to check it but instead I said to myself,what the heck,I'll just move it and see what happens.
Sure enough I just pressed it to move a little and what do you know....it works!!!!!!
Now I know there is something still wrong but this just narrowed it down I think.
Alex22
Well-Known Member
Thats great much better than trying to find a replacement switch.
Please take out a screwdriver and investigate a little before you carry on using it. You could post some pictures of what you find, it should be quite simple to make it safe even if you have some broken plastic etc. Your safety is important to us.
Chuck awker
Active Member
Yeah,I think I will follow and check each connection to make sure there is no touching of wires and such then for the time being,secure it with a zip yie until I fix for good.
The solder tabs on the back of the accessory outlets are only a few mm away from the inner cover panel that hides the rear panel wiring. If that outlet is pushed in a few mm it can easily touch this panel and energize the whole chassis. This wiring is before the fuse, so it’s totally unprotected. Essentially the power cord coming in would short directly to the chassis.
You should definitely get this taken care of before using it. It’s just too big risk!
You should definitely get this taken care of before using it. It’s just too big risk!
Chuck awker
Active Member
Thank you for all your help.Talked to a tech near me and said he will make everything good go 60.00,including financing the out so it's back on the outside.
