Mg50dfx - No Sound Comes Out !

[Lasgo7]

Hi everybody,

I am new on this forum which seems perfect for my question

I have recently put my hands back on my high school amplifier: a Marshall MG50DFX. Great sound, it used to have!
But now that I bought a brand new guitar, and plugged it in... well, no sound comes out ! Such a frustration.

Your help would be greatly appreciated !!

Here is how it goes:
- when connected to electrical supply, it turns ON = the LED is activated, the fan starts to run
- without using headphones = when using the loudspeaker : no sound at all comes out
- when using headphones: sound comes out, either I am using the guitar directly, or a MP3 connected at the back.

Soooo, my conclusions are :
- no electronic in the main PCB is damaged
- problem comes from the loudspeaker, either the loudspeaker directly or the connections to it, etc.

What do you think ? I soooo want to hear some good crunchy sound coming out of it

Arnaud

 

[paul-e-mann]

Probably cost you more to fix it over just buying another one used. You get sound through the headphone so the amp works, check your speaker wire on both ends.

 

[chuckharmonjr]

I smell a fresh dish of fried hocky pucks.

 

[ampmadscientist]

From what you told us so far:
Bad headphone jack.
or blown speaker. Try another speaker, try another speaker cable.

Headphone jack-
it contains switches that disconnect the speaker when headphones are plugged in.
This jack fails, it's a known issue.
Likely you need a new headphone jack. The switch contacts in the jack have failed.

http://elektrotanya.com/marshall_mg50dfx_sch.pdf/download.html