Amp Mad Scientist
Ambassador of Heresy
That issue has been a real thorn in Marshall's side for a while now, probably their most infamous design flaw to date. Its very fixable and easy to do, but honestly, Marshall should have issued a voluntary recall on it since it became such a wide spreading issue. Instead, they released a $250 replacement board and said " F$ck you guys, here!".
That being said though, its a tough as nails amp, amazingly versatile and in my case, unbelievably reliable ( some never had an issue, guess i got lucky lol) Its design continues to this day with amps like your DSL40Cs, which are the same exact circuitry and sound.
The funny thing is that when a Marshall has a major defect they basically pretend that the problem doesn't exist.
They basically tell us they never heard of the problems.
Now, there is a microprocessor defect in the new DSLs.
There is an issue with glue used on the new circuit board that was found to be shorting out the circuit tracks.
But they are as usual refusing to acknowledge.
There are several problems with DSL 40 C, DSL40CR.
People had to return them 2-3 times before the problem was recognized.
People still having issues with the defect microprocessor chip, and Marshall still pretends they never heard of the problem....
seems like the amp forums know more about the defects than the factory does....
When Jim Marshall was alive, these problems were handled differently.
Now it's a corporate cover-up.
I was the first person to create a standard test for DSL circuit boards.
That test is now used world-wide.
Before that test, it was all guessing and random parts replacement.
Now you can check to see if a board is good or bad without guessing.