#1
Hey, recently my Marshall JMD 50watt combo's master volume stopped working properly. as soon as you turn it on the amp just goes as if its cranked, even if the volume is off. I noticed that the knob is loose and it works properly if I push the knob in but it doesn't stay. Can anyone help me fix this?
#2
I assume that like most Marshalls it has a splined shaft? If so, you can try placing a bit of paper over the shaft and then push the knob back on. If that doesn't work, replace the knob. If the spline on the shaft itself is worn round then you'll have to replace the pot.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#4


The spline is the bit on the left that the knob pushes onto.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#5
With the knob off, it still moves and has to be pushed in, now what should I do?
#6
Replace it.
“Ignorance more frequently begets confidence than does knowledge.”
Charles Darwin
#7
take it to an electronics/amp repair guy and have them put a new pot in the amp. You can do it yourself if you are good soldering on PCB's
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#8
What they said. You need a new pot.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band