Bare Knuckle Pickups Forum

Forum Ringside => Tech => Topic started by: psy on July 13, 2007, 01:02:47 PM

Title: Marshall pots
Post by: psy on July 13, 2007, 01:02:47 PM

Does anyone know here I can get new pots for the the master & pre-amp knobs on a JCM800 2203 100w head? They're crackly as buggery & I've got to turn them just right... else I get no sound or a cr@ppy thin sound. Oh, and any idea on what the resistances are? I'll guess I'll find our when I take the amp to bits.

Thanks

Title: Marshall pots
Post by: HTH AMPS on July 13, 2007, 03:36:02 PM

They're both 1M log pots - they'll cost you a quid each from Maplins.

Before ripping them out, try spraying them with a lubricating pot spray cleaner (Maplins also sell this stuff) - I bet the pots are just dirty.  I've never had an amp of any age that had a worn pot.

To clean the pots, spray some pot cleaner like Servisol in the opening of the pot inside the amp.  Rotate the pot ten or twenty times and it should sort it.

Of course you do this with the amp OFF and unplugged from the wall.

 :twisted:

Title: Marshall pots
Post by: c0bblers on July 13, 2007, 04:42:55 PM

Yeah they're probably just dirty, good way to tell is turn them up and down really quickly for a bit and see if the noise goes away a bit.  If it does then they're definately just dirty.  A word of warning though especially if you replace the pots, valve amps are very very very very dangerous things to work on.  Put your hand on the wrong thing and you could get 500+ volts using you as a short cut to ground, make sure the filter caps are discharged if you're going to be soldering anything.

Title: Marshall pots
Post by: Will on July 13, 2007, 04:46:53 PM

Have you tried contacting marshall?
and they don't charge too much for postage

Title: Marshall pots
Post by: psy on July 13, 2007, 07:40:13 PM

I've not tried marshall yet.  I just assumed they'd charge an arm & a leg for a sucha simple component.

I've got a can of switch cleaner kicking around.  I'll give that a wurl in the morning.

Cheers guys

Title: Marshall pots
Post by: Will on July 13, 2007, 07:51:36 PM

i got some fuses from them i think - i live near to the factory, so i just asked for the appropriate ones. prices aren't too bad i would say

Title: Marshall pots
Post by: andymac on July 13, 2007, 11:40:37 PM

Try Marshall.  You can book it in for a service.  They used to charge cost for componants used and labour was reasonable.  

Andy