Trouble with Mesa Boogie subway D800

Have you tried a new speaker cable and known good speaker?

If this doesn't help, give customer service a call and they will get this sorted out for you.

 

From the manual:

POWER LED This blue LED indicates that the amplifier is connected to a power source and is switched on, operating correctly. If this LED is not on, double-check the power source, and be sure the power cable is firmly inserted into the IEC power inlet socket.

PROTECT LED This red LED indicates that the amplifier has entered protect mode and is either protecting itself from an exter-nal fault (such as a shorted speaker cable or defective speaker), or that there is an internal fault within the amp itself. Verify that it’s not a fault external to the amplifier by disconnecting all cables (except the power cable) from the amplifier. If the protect LED is no longer lit, the problem is most likely a bad speaker cable or defective speaker. Testing with a set of headphones can help to narrow down the problem, as the headphone signal is derived post-power amp using a frequency compensation, cabinet emulation network.

LIMIT LED This amber LED indicates that the power amp is nearing maximum power and is entering the soft clip/limit output tube emulation mode. Soft clip/limit output tube emulation mode mimics many of the desirable characteristics of tube amp output stage overdrive while eliminating the common solid state clipping artifacts. There is approximately 6dB of range on this circuit, driving beyond this, of course, will cause gradual output stage clipping. It’s acceptable for this amplifier to operate in output stage overdrive mode (if that’s the tone you are after) with the LED flashing roughly 25% of the time on.

 

Try/check the mute switch?

SYMPTOM NO AUDIO OUTPUTIs the power LED lit and do the indicator LEDs over the function switches work? NO: Possible causes to check in this order are:1. Verify the power source, verify that the IEC power cable is not damaged and is fully inserted into its socket,.2. Verify that nobody unplugged your amp or turned off your power strip when you weren’t looking (if so, blame the guitar player, turn on and play.) 3. If these do not solve your problem, it’s possible that your amplifier has failed so call our customer service department and we will help you get this resolved.YES: Possible causes to check in this order are:1. MUTE switch engaged (turn mute function off)2. INPUT or MASTER controls turned down (turn the controls up)3. Defective speaker cable or cabinet (test known good speaker cable and cabinet)4. Defective bass or cable (test with known good bass and cable)5. There is indeed a problem with your amp, call our customer service department and we will help you get this resolved.

 

Is the limit LED on with no playing, or does it flash with hard playing?

With the limit LED flashing, this confirms that the signal path is operating properly through all preamp circuitry. The problem is either within the speaker, the speaker cable, or the power amp.

 

OK, there is a problem with your amp. Give customer service a call and we will get it sorted out for you.

 

I had this happen with my D800. Turns out one of the potentiometers on the front (master) got bumped enough to break it, though I don't remember anything ever hitting it. Though not covered by warranty, Mesa did a great job of repairing it quickly at a low cost.

 

Like I've stated before, "ya' gotta love TalkBass".
I've been able to communicate with the very people that have made my basses. amps and effects and have had them answer questions right here on the forums. Too cool!

 

Preach! And @agedhorse not only takes care of his current customers. But he does what he can to help out customers of companies he doesn't even work for anymore.

 

This is one possibility, though generally there will be a loud squealing noise present and the amp may enter protect while this is happening.

 

Mesa will take care of you, they stand behind their products, no worries!!

 

+1

 

It’s broken. Gauge fixing vs replacing.

 

I actually had a few seconds of popping/squealing before I lost sound all together so that makes sense.

 

Are you kidding?

The amp is still under warranty and won't cost anything unless the fault is due to mechanical damage from being dropped. Even then the cost to repair out of warranty is inexpensive. This is not disposable junk, it's entirely serviceable (by a qualified service center or the factory).

 

Possibly. Do you recall the amp taking a fall? You can PM me and I can go over some troubleshooting with you.

 

I wasn’t saying it’s a junker. I must have missed still under warranty. These threads get so long sometimes, I missed part of the conversation. My bad.
I had a Markbass head certified repair and it worked fine after that. However, I lost my trust in it and eventually sold it.

 

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The MarkBass story is cool but... I don't see how you losing trust in a repaired amplifier, of a different make, repaired by different people, which was working fine, helps the OP either...