MkIII EQ probelm

[keithus77]

Hu guys,

I have a MkIII and the EQ seems to drop in and out. If I touch the EQ sliders it drops out and then if I tap on them or the front of my amp it will usually cut back in.

Anyone know where the probelm is likely to be located (ie behind the EQ or the EQ-in-out switch)? Is it an easy fix?

Cheers

 

[LUCRETIA]

Sound like something is loose...Connection???

 

[BPski]

It may also be the switch. Worn contacts. Or the loose connection/bad solder joint.

 

[Boogiebabies]

:shock:

 

[BPski]

Worst case with the switch is put in a new one. They are probably pretty cheap. I think it's a Carling. There are alot of suppliers for them. I had a similar situation with my Lead Master pull switch on my Mk IIB. The switching contacts were oxidized a bit. I shot some cleaner in and actually did not help. Being the nut that I am I took apart the pot/switch and flipped the switching mechanism upside down so there was fresh metal to contact. A little obsessive I know but it worked. I would not try it with the EQ switch because they are easy to get. The old style pull pots from what I understand are a little hard to find.

 

[keithus77]

Is replacing the switch the best way to go?

Also, the amp head is full of dust (probably never been cleaned) and this could be a cause. Do you recommed cleaning the head with pressurised air (like the kind that come in an aerosol can)?

Cheers

 

[BPski]

When I dust out an amp I use a can of air and have the shop-vac nearby to kind of catch the dust. I would spray out the switch before I replace it. Knowing that the chassis is full of dust may mean that your switch is too. Try the spray. If it still does not work correctly then start looking for bad solder joints or loose connections. Use a sharpie magic marker to tap around the PCB's to find the bad joint. I hope this helps.