Replacement pot for Mark III

[Podicle]

Well, after just returning from a jam where my old 60w Mark III stole the show, I slipped carrying my amp and sheared of the volume/pull bright knob (the left-most pot when looking at the amp).

Can anyone point me towards an exact replacement? I live in Australia but assume I'll have to get one from the US. It obviously has to have the right diameter shaft to fit the knob.

Any help much appreciated.

 

[zodiac272]

It's probably a 250k or 500k audio taper...but I'm not sure since it's a pull pot. And probably any good electronics store should have them. To find the value with a multimeter, I thing there are two parts that sum together to get the total resistance, so place the leads on the right two tabs and measure resistance then place the leads on the left two tabs and repeat. There should be three tabs on the pot. Add both together... If you get like 450 it's a 500k and if you get like 200 or more it's a 250k.
I'm not too experienced with this stuff, but I don't think I'm that far off. Somebody else please help out... And for the love of god get some kind of case! Lol good luck!
Scott

 

[kdorsey]

According to my specs, the volume pot is 1M ohms w/ single pole, single throw (SPST) switch. Oh, and it's more than likely linear taper (you don't want a huge bump in volume between 7 and 10). I highly recommend making a call to Mesa and buying the part from them. There were constant variations in design over the life of the MkIII and only they can reliably tell you after referring to your serial number...unless one of the gurus around here knows this off the top of their heads.

Don't feel bad. At 63.5 lbs., it's amazing we don't make more mistakes after a hard night of playing. My 2x12 cabs have a million scrapes!

 

[Podicle]

Thanks guys. kdorsey, are you sure it is linear taper? I thought it would be log.

 

[kdorsey]

No, I'm not positive and easily could be wrong. If I have time tonight I'll crack the chassis and have a look. It's also possible to have a custom taper, which I used to sell into many amp designs. We'll see.

 

[kramerxxx]

I had the same kind of problem with my Mark III. I called Mesa, they sent me a new replacement knob and pot and I didn't need to figure out what I needed. The price was fair and installed them myself in about 30mins.

 

[UsrName]

I had the same kind of problem with my Mark III. I called Mesa, they sent me a new replacement knob and pot and I didn't need to figure out what I needed. The price was fair and installed them myself in about 30mins.

Yes, I did the exact same thing with a mark iv. Called boogie and they sent me the pot in about a week, also a new knob because the part number had been changed and they use shorter shafts now. So, it worked out to be about a $10 repair!