Pot values for 1982-1983 Thunder 1A

by neilcharkow Fri Nov 08, 2024 9:38 pm

Hi All.

I'm a new member and new owner of my first Westone.

I need to replace the pots as they're very scratchy.

I've had a look at the specs and I believe mine is Active Circuit V2.

Based on the specs, my volume pot is a 500K log (audio). However, the detent pot is in the centre and V2 states,

The volume and tone pots are 500K log
The active tone pot is a 500K linear pot with a centre detent

I'm a bit confused as my centre pot, which I believe to be a tone knob, has the centre detent.

The third pot (closest to the input jack) is activated by the mini switch indicating to me that it's the active tone pot and it does not have a detent.

With the active circuit turned on via the third (bottom) toggle, the middle detent tone works. However, with the active circuit turned off, there is no tone function. Is that how they're supposed to be.

Because detent pots are very difficult to source in Australia, what is the function of the detent and can it be replaced with a standard 500K top?

Thanks in advance for any information you can supply.

Pot values for 1982-1983 Thunder 1A Unname11

Pot values for 1982-1983 Thunder 1A Unname10

by **Barry** Sat Nov 09, 2024 1:09 pm

Hello Neil and welcome.

For a description of the T I-A controls see the owner's operating manual: LINK

As far as the pots are concerned I would save yourself a whole lot of aggravation and expense by simply cleaning them liberally with electronic contact cleaner.

To do this properly you should access them via the control cavity and squirt the liquid directly into the pot via any appropriate opening. Then, yank it like a monkey in a Mango tree! What a Face

This may require more than one application. Allow enough time to dry before using.

Attempting to do it from the player's side (shaft) does not normally go well unless you have a custom cover for doing that. Even then. . .

The wipers on all potentiometers, especially on vintage guitars like Westone, are susceptible to oxidation over time. Scratchiness is annoying but usually not fatal, and not normally grounds for replacement unless you are still experiencing serious drop outs after a thorough cleaning.

by neilcharkow Thu Nov 21, 2024 7:32 pm

Hi Barry,
Thanks for your suggestion. I've liberally sprayed contact cleaner into the pot with little to no difference. Because it's scratchy over such a small portion, I suspect it's where the wiper sat on the element for many, many years based on the general condition of the guitar when I bought it. I think my only option now is to replace the pots which I'm comfortable doing. Research has so far told me that replacing pots on these guitars does not negatively affect their value, i.e., it's not a '59 Les Paul. Also, I need to replace one of the mini pots so she'll be open for surgery anyway.

Thanks again for your response.

BTW, sorry for the late reply but I just got notified by email today of your reply almost two weeks ago.

by **Barry** Thu Nov 21, 2024 9:36 pm

Replacing the pots can be a normal maintenance item on an older guitar that has been in storage for a long time.

Sometimes there is just too much corrosion to re-establish a good contact surface ( I am assuming that you worked the control vigorously after spraying, yes? gotta do that)

It's always preferable to try and restore if possible, but if changing out components results in a reliable playable instrument then there's no sin in that!

by beeflin Sat Nov 23, 2024 4:21 pm

neilcharkow wrote:I'm a bit confused as my centre pot, which I believe to be a tone knob, has the centre detent.

The third pot (closest to the input jack) is activated by the mini switch indicating to me that it's the active tone pot and it does not have a detent.

With the active circuit turned on via the third (bottom) toggle, the middle detent tone works. However, with the active circuit turned off, there is no tone function. Is that how they're supposed to be.

Yes.

The tone control with a detent is an active (powered) bass boost (down from detent) or treble boost (up from detent). It only works when active is ON.

The tone control without a detent is a passive treble cut and should work all the time.

Because detent pots are very difficult to source in Australia, what is the function of the detent and can it be replaced with a standard 500K top?

Definitely not. The detent switches between two different functions and gives a flat tone setting.

by neilcharkow Sat Nov 23, 2024 5:26 pm

Thank you beeflin for the description of what and how the detent pot functions. You've saved me time and money replacing it with a pot that wouldn't have functioned properly. I'll start scouring the internet for a 500K detent pot. I'm assuming is linear (currently soldered over). It's only got a bit of oxidation in a small spot so I might continue spraying with contact cleaner and live with it. It's mainly the 250K active pot that's causing me issues.

All in all, I'm really enjoying playing the guitar, getting to know its ideocracies and joining this group.

Thanks again.

by 1point5 Mon Dec 02, 2024 2:07 pm

Yes you can replace it with a regular pot, you just won't have the so-called neutral position to return to in the centre of the sweep. Whichever way you slice it the pot travels 0-500k regardless of centre detent or not, the only change is you'll have to manually dance a little bit to find the middle during play, should you care about such things.

Otherwise, not sure I read you right but the usual tone control is the middle knob and that works like any other guitar. The third knob by the jack (that controls the active tone circuit) only works when it's engaged, otherwise its not in the signal path.

by neilcharkow Mon Dec 02, 2024 10:43 pm

Thanks for your answer. I got one "Definitely not" and one "Yes you can replace it" but I believe, from other research that they are just like normal pots except for the centre detent. There are ones that are double stacked that are used for balance volume (left/right) but others that just have a centre or multiple detents that are used on stereo volume knobs.

I've ordered a 500K Linear Centre Detent pot and am waiting for it to arrive. I'll check it's characteristics against what I pull out of the Westone and confirm before soldering anything in.

All my attempts to clean with contact cleaner have failed. The main volume pot actually seized while I was turning it back and forth indicating it must have been very corroded to start with. This guitar had been in storage for years when I bought it so I'm not surprised.

Thanks again for your reply.

by 1point5 Mon Dec 02, 2024 11:45 pm

Yeah if it's gone it's gone, no amount of contact cleaner or CRC will help that. And electronically the circuit doesn't care if it's a centre detent or not, it'll just use what's there and the operator will work it out.

by Sponsored content

Pot values for 1982-1983 Thunder 1A

Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A

Re: Pot values for 1982-1983 Thunder 1A