Alembic Spoiler Scratchy Tone pot/ treble dropping out

[bassvibes]

I have just bought a 1984 Spoiler bass, but it might have a fault.  When a turn the tone knob it is a little scratch when I try and get some treble tone from it.  Sometimes the treble drops out when I turn it and have to turn knob backwards and forward to engage the treble again.  It seems like the pots are sealed so no point in spraying with lubricant.  Any ideas what the issue might be?  I've added image of electronics in the bass

[gtrguy]

First try spinning the self cleaning pot back and forth 50 times.

[David Houck]

As gtrguy David said, and as stated in our FAQ section, the pots are self-cleaning.  Turn them their full travel back and forth maybe 30 times or so.  That should clean them up.

[lembic76450]

Also, make sure that the body of the tone control is not loose or turning inside the control compartment.

[bassvibes]

I have turned the tone control quite a few times and unplugged and plugged the ribbon connectors, and it seems to have worked.  Hopefully sorted - thanks

[edwardofhuncote]

As a matter of habit, and just so that they get exercised equally, I rotate both the Volumes and Filters on my Alembics five cycles every time I plug up to play. Same for switches. Granted, five is probably excessive, but it eliminates all squealie-dealies, cracklies, static-y nonsense, and other unwanted issues that cause sonic sadness.

~Gregory (who also turn the labels on soup cans the same direction and can't stand a crooked area rug)

[keith_h]

- snip -
.... and can't stand a crooked area rug)

Just something for you to think on. The rug will never be straight if the house is out of plumb and floor boards aren't parallel. Of course there is always wall to wall carpeting. 

[lbpesq]

Sounds like we may have some Monk fans around here!   

hehehehe

Bill, tgo

[bassvibes]

As I said I am new to Alembic, but I wish I bought one of these years ago.  This is an amazing bass.  It plays so well and the sounds on offer are awesome. 

So if means the rituals of knob turning to keeps it sounding so good so be it.

[edwardofhuncote]

Sounds like we may have some Monk fans around here!   

hehehehe

Bill, tgo

[raises hand, timidly...]

- snip -
.... and can't stand a crooked area rug)

Just something for you to think on. The rug will never be straight if the house is out of plumb and floor boards aren't parallel. Of course there is always wall to wall carpeting. 

I'm not this far gone yet-

But seriously, Welcome to the Alembic Club. There's nothing like a lowpass filter circuit. 

[bassvibes]

Sadly the problem hasn't gone away.  Does any one else have any ideas?  Or is a new pot?

If it is a new pot can anyone recommend an Alembic tech in the UK?

Thanks

[mario_farufyno]

You always can replace it, contact Mica.

Some time ago I broke my Rogue's volume pot shaft when trying to take the Knob off without knowing it was far different from the usual guitar knobs. It kept working but after some years it started to fail more and more and I had to substitute it (although it was just a volume drop when fully open, no scratchy noises in my case).

[bassvibes]

I managed to identify the problem with the scratch pot.

It is the jumper plug that sits behind the tone filter pot (see pic).  There is a lot of play in it causing the connection to moved with slight movement from the pot.  I have put something against the jumper to stop it moving and it worked - pot is absolutely fine.

Anyone had this before or know of a more permanent fix?

[David Houck]

You should make sure the pot is sufficiently tight against the body.  Your bass probably has "hat" knobs, with two tiny set screws that need to be loosened to remove the knob from the pot.  Be careful not to drop the screws on the floor.  Then tighten the nut that holds the pot against the body.  Don't overtighten; just firm so that the pot doesn't move.

[keith_h]

Other than replacing the connector a dab of silicone on one side where the male and female connectors meet is often enough to stabilize a loose connector. Just be sure they are properly mated before you place the dab and that it does not move until the silicone sets. Should you need to take them apart in the future it will be a bit more work but nothing an Exacto knife can't handle.