250k / 500k which is it

[fleabag]

I'd like to determine the k ohms of some pots in one of my basses

Firstly, can i do this while they're still all connected and if so, which tabs do i stick the red and black multi meter cables on and which setting on the ohms scale do i use

TVM

[Norris]

You would probably need to disconnect any wires to get an accurate reading, and it will be between the two outer lugs. It doesn't matter which test lead goes to which lug for measuring resistance. Adjust your meter range until you get a sensible reading (probably on the 100k or 1M setting) - you won't damage anything on a passive circuit

While you're at it, should be quite easy to work out if the pots are linear or logarithmic. Having measured the resistance between the outer lugs, measure between an outer lug and the middle and twiddle the knob until the meter reads half the full resistance. If the knob is about centred it's linear. If the knob is nearly full on or off it's logarithmic 

[fleabag]

Ooh ta Norris.  Bit of a bar steward about having to remove the pots.  Its packed in there and hard to see much  ( blend, vol , 2 tones )

[Norris]

The pickups would have a much lower resistance and would affect your measurements if still connected. The only way to measure the pots accurately is in isolation 

[JapanAxe]

Leave the soldering iron alone for now. Assuming a passive bass, select one pickup only, connect your meter across the output. Slowly turn the appropriate volume pot through its range and note the maximum reading, which will be somewhere in the middle of the sweep. Double that for the approximate pot value. The nominal resistance of the pot will be a 'round' figure, so if you get 257k, that would indicate a 250k pot.

[fleabag]

Thanks JA - i will give that a go