This model has a breaker on the back did you try that? Have you checked the speaker connections and other connections?
SOURCE: amp will not come on
hi thanks for using fixya!!
On this error, you should check still the built in breaker.
SOURCE: Marshall MG50 DFX makes a squealing noise on power up
Yep, chalk that one up to poor design...The amplifiers are going out of balance during power up and down. Two seconds is pretty long... Try turning down the gain during power on and see if that affects it.
The pop on turning off is normal... None of these have speaker disconnecting hardware that is necessary for very high power amps. The biggies have hardware that checks amplifier is balanced before connecting the speakers and a relay also cuts the speakers immediatley on power down. As power goes up and down the circuitry comes to equilibrium and until it does, strange things happen.
I would investigate the CONDITION of the filter caps for the main power because if they age to a higher internal resistance that COULD cause the high freq oscillation on power up... Two seconds is MUCH too long.
There should also be some non-electrolytic caps NEAR the power output transistors to handle high frequency supply power bypassing.
Check the power bypasses that service the preamp stages. Look for pregnant electrolytic caps that have failed.
Ultimately, you MAY need an oscilloscope to isolate the high freq problem.
Testimonial: "Thanks - great advise! The gain position makes no difference. I'll try to chase the problem with my Tek Oscilloscope ;-)"
SOURCE: MPC2000XL MCD not working anymore..HELP PLEASE
If the unit uses a power adapter, check that the adapter is providing the correct voltage.
SOURCE: I got a Marshall MG100HDFX for free from a friend
The power amp section has blown parts. You will likely find they use a chip like the TDA7293 as the power amp output and it will be blown, shorted causing the fuse to blow. These cost $6 from Digikey.com. Find a competent tech to replace it and use heat sink compound. Verify the part before ordering one. They come with leads bent either way so make sure you get the one with a matching suffix letter. When firing up after repair, put a 60 watt light bulb in series with the hot power lead to act as a current limiter... saves blowing fuses if there is another problem.
Testimonial: "Awesome. Helped me out a lot! Me being a greenhorn when it comes to electronic, I appreciate it!!!"
SOURCE: My Fender Hot Rod deluxe makes a popping noise when switching back to the clean channel.
I have seen this problem before. If not a valve issue check supply smoothing caps 22uf 500v
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