Bricked my amp?

[Prolix]

A good while back I was messing around with my surround speakers and dropped the connector of an active high-level speaker cable onto an input on my Rotel RMB-1555 amp. Sent out a booming drone for a couple seconds until I snatched it off. Yep, I'm dumb. Now when I turn it on I just get a flashing power led (which I believe is the power protection fault alert) and no sound. Manual says the circuit resets itself if it can, but it hasn't. Rotel authorized repair shop wants $300 just to diagnose the issue, almost half what I bought it for.

The fuses look good. I see no physical damage. Didn't smell anything weird. Any ideas? A while back I poked around looking for a fix and didn’t find anything. I'm cleaning out the basement and seems a shame to just toss it.

 

[MaxwellsEq]

Have you tried performing a factory reset?

 

[DVDdoug]

$300 for a diagnosis without a maximum would be too much risk for me. You might be able to sell it as-is to someone who wants it for parts, or if they want to attempt a repair themself, it that makes you feel better than throwing it in trash.

It's often more expensive to repair than replace something because electronics is built on an assembly line with lower-skill labor. It requires skilled labor to diagnose & repair and it might take more man-hours that it took to build the thing in the 1st place!



A long time ago I re-built an amplifier, just using the case, and major components of the power supply, etc., because the original parts were no longer available... But no, I'm not saying I want this project...

 

[AdamG]

Have you tried unplugging the unit from power and let it sit unplugged for a few hours. Once disconnected from power push the power button a few times to drain any residual capacitor juice. Worth a try if you have not yet done this.

 

[Prolix]

Have you tried performing a factory reset?

I couldn't figure out how actually. The manual says if the fault doesn't clear itself after being unplugged for a few minutes you should contact a repair center.

 

[Prolix]

Have you tried unplugging the unit from power and let it sit unplugged for a few hours. Once disconnected from power push the power button a few times to drain any residual capacitor juice. Worth a try if you have not yet done this.

Yeah, just tried again after it sat unplugged for months.

 

[Dunring]

Only thing is see if there's any button to hold while turning it on. If it's been off and capacitors drained to reset it I don't think anything else will help reset it. Maybe support will know a trick if one exists.

 

[AdamG]

Only thing is see if there's any button to hold while turning it on. If it's been off and capacitors drained to reset it I don't think anything else will help reset it. Maybe support will know a trick if one exists.

Good thought. Some amps you hold the power button down/in as you restore power and that might force a reset.

 

[Timcognito]

Sounds like the fuses for these amps are finicky so for $20 bucks on Amazon you can replace them all. there is a chart in this post
https://www.reddit.com/r/BudgetAudiophile/comments/nqpnvv

 

[restorer-john]

Don't toss it- that's just an incredible waste of a lovely amplifier.

It's most likely you've taken out one channel output devices or rail fuses and the amplifier is protecting itself. Whatever, it would be anything from a trivial to an easy repair for any competent technician.

When you check fuses, don't just look at the filament of wire- test the continuity. Many times a fuse may "look" good but has vaporised under the cap near the end and it looks perfectly fine. I once bought a $6000 amplifier for $300 as parts because a "technician" who should have known better declared the power transformer had an open primary and it was a write-off. He had visually checked the M205 line fuse and tested the primary as open circuit. A 20c fuse fixed it.

 

[Prolix]

Sounds like the fuses for these amps are finicky so for $20 bucks on Amazon you can replace them all. there is a chart in this post
https://www.reddit.com/r/BudgetAudiophile/comments/nqpnvv

Thanks, I just ordered a new set and we'll see!

 

[MaxwellsEq]

I googled "factory reset" for your amplifier and it returned a response apparently taken from a different manual

Support | Page 10
In some circumstances it may be helpful to perform a factory default reset on the unit. This can be done by powering on the RC-1580, then pressing and holding

There may be a common process for your amplifier. It's worth digging as much as possible.

 

[Prolix]

Thanks all. I swapped out the fuses, and tried everything I could think of to trigger some kind of reset, but no dice. I did find a reasonable repair shop but the wait is going to be 4+ weeks. Guess we'll see.

 

[AdamG]

Thanks all. I swapped out the fuses, and tried everything I could think of to trigger some kind of reset, but no dice. I did find a reasonable repair shop but the wait is going to be 4+ weeks. Guess we'll see.

Please remember to give us an update. Sorry we were unable to help you but maybe we can help the next person out once we know exactly what happened to your Amp. Good luck with the repairs.

 

[ZolaIII]

Did you try to find reset for protection mode lock down? Usually it's combination of physical keys pressed together with power buttons on switching on.

 

[Prolix]

Did you try to find reset for protection mode lock down? Usually it's combination of physical keys pressed together with power buttons on switching on.

The issue is the only button on this thing is the power button.

 

[restorer-john]

If you hear no relay noise after a few seconds when turning on, and you've inspected and replaced the 10 rail fuses (2 for each channel), then you are likely to have taken out 1 channel with your exploits. That will be a set of output devices and maybe a few drivers/emitter resistors. Not expensive, but time consuming.

Just check there is not a line fuse under the black elephant-hide/plastic power switch terminal cover behind the front panel (front left).

 

[Mikig]

a similar problem happened on a Quad final. Moved and mounted in another system, probably an adjustment maneuver moved a cable that was not properly tightened.
The two wires of a speaker cable have touched.
I also tried with fuses, but nothing.
Brought in for assistance. Diagnosis? transistors gone...repaired with 200 euros, now it works great.