Amp Shutting Down, need help


I have a Cary 7.250 brand new amp that shuts down after 20 seconds in my NYC apartment. I have sent the unit back to Cary where it tests fine. I have tried the unit at my friend’s apartment and his place of work and it works fine. The unit is 100% in working order. After talking to many people I was told to attach a 50' extension cord and low and behold it worked.

The good news is that I have a dedicated 20amp circuit to this outlet. My voltage reads 118 volts and Cary said that is not a problem as the unit will work between 90 and 130 volts. I have tested for voltage on the negative lead to ground and there is no stray voltage. I have also tried the unit on other outlets in the apartment and the same problem occurs.

My mono blocks and all other components work just fine. So I’d love to hear suggestions as to how to get rid of this 50’ extension cord?

Thanks in advance.
sailcappy
Currently I have a dual outlet connected to a 20amp circuit. That circuit is shared by one other outlet in my apartment. I plug the SR Powercell into one of the slots and my JL sub into the other one. All my other equipment is plugged into the SR Powercell.

My plan is to first keep the same power path for everything and put the DC blocker between the SR Powercell and the Cary Amp. I might also try to put it between the SR Powercell and the wall outlet. Stray DC should be bad for all my other components, right?

If all this fails I will then sell this DC blocker to anyone who wants it on AG. I will then try the Brick Wall and play with the same signal paths as the DC Blocker.

Does this sound like a plan?

Ken is gone on vacation for a few weeks so I will try these solutions as they are not a real budget buster. If they don't work I can always sell them.

Finally if none of these suggestions work I will try to work with someone who can help me re-configure the current 15 amp circuit breaker with something that is less sensitive to inrush current. It will probably void my Cary warrantee but I can’t have this extension cord in my living room anymore.
Sounds like a plan to me, except that my instinct would be to avoid configurations in which the Brick Wall and the Power Cell are used in series. If you are using both, have them both plugged directly into the wall.

Also, given the small difference in price between the two versions of the Brick Wall, I think it would make sense to get the 8-outlet version. That would give you the flexibility to experiment with what gets powered from where.

Regards,
-- Al
Sailcappy, I am really sold on the idea that the breaker is at fault. Have you been using it as a power switch? Or is the amplifier designed with it being the power switch?

Either way what I would do is replace the breaker... troubleshooting from a distance is always tricky, but we can be very sure that the solution has to do with the inrush current on the power transformers.
08-24-12: Atmasphere
"Sailcappy, I am really sold on the idea that the breaker is at fault. Have you been using it as a power switch? Or is the amplifier designed with it being the power switch?"

Based on the mag-breaker's rear location, the amp's remote-trigger feature, and front-actuated Power/Standby pushbutton switch, it's intended as an "actuate-and-leave it" protection device. Although, with all his troubleshooting prior to and well after Cary's diagnostic testing, that particular mag-breaker has probably been subjected to several dozens of set/trip cycles. Certain internal electro-mechanical aspects could be deteriorating, though lacking the component's specs/data information, and additional dianostic measurements, it's an educated assertion - something most experienced techs would investigate in any applicable field of electronics.

If the two filter options fail to resolve your issue, I wonder if Cary would sell you a replacement breaker. Is your skillset up to changing that component (which *should* be a breeze), or maybe your friend could do it rather than sending the amp back? Even if Cary won't sell you one, the component's mfr info/PN is probably still available on the breaker's body once it's accessed within the amp (possibly by removing the bottom panel) - thus likely availability unless a custom-spec'd option.

Frank
When the problem first occurred Cary sent me a new circuit breaker which is the ON/OFF power switch. I installed it which was easy to do. The problem is not with the breaker being defective. Remember it works fine at Ken's place of work.

My updated plan is to:
1. Try the DC Blocker if that does not work....
2. Try the Brick Wall if that works I will replace the SR Powercell with the Brick Wall.
3. If the Brick Wall does not work then I am at a loss.