Marshall MG15CD Input Jack Fix

Someone had attempted to repair this little practice amp, and now it was still not fixed and there were parts missing to boot.  The Unbrokenstring Crew To The Rescue!

Finally, something that is not made in China!  I’ve worked in South Korea in loved it.  Wonderful people.

The input jack is supposed to be soldered to the circuit board, but the solder joints failed completely.

Strictly speaking, it’s poor practice to use electrical connections for mechanical attachments, but once we moved from point-to-point-wired amplifiers to circuit-board-centric amplifiers, jacks and potentiometers were suddenly used as mechanical mounting devices as well as electrical components.

So let’s start by removing all the old solder and cleaning out the holes.  You can see here that these are not plated through, which works in our favor.

The other half of the joint is the component leg.  Oops, these have failed in the mechanical aspect.

So let’s add our own new legs.  Prosthetic leads for input jacks?  Maybe someone will write a song about it…

We’re ready to go back into the circuit, with fresh copper leads which should work as well as the old component legs.

We need to be quick when soldering these new legs to the circuit board, or we’ll melt the work we’ve already done.

I think we’re ready to begin reassembly.  The circuit board is entirely supported by what you see here.

The screws that held the chassis to the top of the amp enclosure were missing.  We used some extra screws from the shop to replace the missing mounting screws.  New ‘Tinnerman’ nuts were located and pressed into service.  I think this is going to work!

I think Erika is happy with her repaired amplifier!


Thanks for reading all the way to the bottom.

David Latchaw  EE