I donnt think you can solve it the amps must be blown up and i dont think you would know

Unless the person that analyzed this problem used an oscilloscope and did detailed troubleshooting, I would NOT jump to the conclusion that aan op amp was blown BASED upon my looking at the schematic of the unit. There are MANY components involved with the overdrive channel, including relays and other transistors and components. The most probable caause would be that 1/2 of the V2 vacuum tube is burnt out. Test by swapping V1 with V2. If NOTHING works, then replace the tube that is NOW in V1 as the second section of it has a burnt out heater. Also a bad potentiometer for the OD channel would be a suspect. A VERY common problem is broken solder at pot terminals. Try plugging a set of headphones into the preamp output. See if you can hear sounds in bothe OD and clean channels. Note you will only hear sound in the LEFT headphone as the preamp out is MONO. MOST of the three op amp chips would NOT kill the OD signal if they were bad.

How are we to even know what brand mixer you have... and have you tried it using your CORRECT adapter. Most mixers are pretty well protected against using wrong adapter. Many require an AC voltage input rather than DC and use of a DC adpater will not damage one unless the voltage is very high.

Another person posting on here I suggested opening his unit and he had blown speakers. I think these that are DOA after previous use may be blown during the previous shutdown of the amp driving them and those with built in amps are blown when mixer is powered down putting out a large pulse. Hopefull the amp is blown rather than the speakers... cheaper to repair. Open and check for a fuse, but dont' replace it until you find out the cause of it blowing as additional damage can occur.

no fuse in there unfortunately.

The problem could either be a blown tweeter (but that would likely cause distortion rather than silence) or a fault with the amp or crossover. Often it seems a relay is at fault in these instances with dynaudio monitors. In any case, unless you have considerable electronics knowledge (which I think it's fair to assume you don't ?) you won't be able to fix em yourself. Give dynaudio an email or call - they're helpful.



Dynaudio North America
1140 Tower Lane
Bensenville, Illinois 60106
USA

Phone (630) 238-4200
Fax (630) 238-0112

For Service: [email protected]

try a differrent speaker of suitable wattage and ohmage (displayed with a number next to a ? symbol on the back of the speaker),

or

remove the original amp speaker and gently push in and out on it, checking for uneven resistance or scratching. the speaker should retract and return smoothly, without any scratchiness or uneven resistance from within, and if there is any of this scratchiness or uneven resistance from within, the speaker is likely damaged from too much wattage or distortion.

use boss power supply

We have a Yamaha keyboard YPT-330 note E and F sharp not working why?

http://www.fender.com/support/amp_schematics/pdfs/Bassman_400_Schematic.pdf Also note there is a thermal protection circuit and a current overload. If the amp turns on and there is no sound start with the speaker to make sure it isn't blown and work backwards through the wiring and connections up to the crossover circuit (all in one cabinet version). On the head separate versions check for a broken output jack problem. The fuses are 10 amp 250 volts for the 100-120 volt models and 5 amps 250 volts for the 230-240 volt models. NOTE: If you are at all unsure about opening your amp up to work on it, take it in to be serviced. It doesn't sound like a fuse problem to me. Necer work on an amp while the power cord is plugged in. Always replace parts with the proper replacement especially fuses. They are there to protect the circuits. If they keep blowing it means there is an internal problem. Remember that capacitors store a lethal charge and it is easy to touch the wrong thing when you are looking inside an amp even if it has been disconnected from power for a while.

The output transistors may have shorted and caused a resistor to smoke (literally!!). This should not be too expensive a repair for anyone that works on these amps. Figure on $20-$30 for parts.

Dan