Need help determining the value of a potentiometer

[Henry89789]

I am trying to find out the value of an old pot whose shaft pulls out of the body.  I am trying to find a replacement  but the pot does not have typical marks such as  "A100K".  I tested the pot with a multimeter (dial set to  200k ohms) and got a reading of 101.1.  The only markings on the pot are  "CTS", "USA",  "204-1040",  and "1376927".  Can anyone help identify the value of this pot?  Thanks in advance for any help with this problem.

[Mark Hammer]

Unless you paid $20 for it new (unlikely to be found in any commercial pedal), precious few pots will measure exactly the same as their nominal value printed on the chassis.  This one is obviously a 100k pot.  The key question is what the taper is.  If you are able to, measure the resistance between one outside lug and various points along the resistive strip.  That should provide clues as to the taper, so you can get a suitable replacement.

As always, start here: http://www.geofex.com/article_folders/potsecrets/potscret.htm

[Mike Burgundy]

CTS numbering codes are probably something like (compared to nowadays): 204-104-0
Type 204 (no longer made i guess, points to the enclosure and shaft style/size)
value 104 - 10x10^4 or 100k
taper 0 - no idea what that means. nowadays 1 is lieanr, above that are different tapers. My *guess* would be linear.

What did the pot *do* - that's often a big clue. Most volume/gain pots are log/audio, rest often is lin.

[LucifersTrip]

have you tried CTS?

http://www.ctscorp.com/feedback/techinfo.htm

[Henry89789]

Thanks for the replies.

Sorry I forgot to mention it is a volume pot on a solid state amp. An old (about 1970) RMI 140 made by Rocky Mount Instruments  of Rocky Mount, NC. It came with a matching cab that has a JBL D130F   15" speaker. The amp with this speaker sounds very good.

If one were to have to make a decision and choose a pot based on the information I provided here what would be the best choice?      an   A100K pot?    Or something else?     Thanks. 

[mattthegamer463]

Thanks for the replies.

Sorry I forgot to mention it is a volume pot on a solid state amp. An old (about 1970) RMI 140 made by Rocky Mount Instruments  of Rocky Mount, NC. It came with a matching cab that has a JBL D130F   15" speaker. The amp with this speaker sounds very good.

If one were to have to make a decision and choose a pot based on the information I provided here what would be the best choice?      an   A100K pot?    Or something else?     Thanks. 

An A100K pot would do the trick.  If you want to confirm that it is indeed a log pot, you could take measurements at 0%, 20% 40% 60% 80% and 100% of the rotation, measuring from one wiper to the other.  If you see 100k, 80k, 60k, 40k, 20k, and 0k, its clearly linear.  If it drops off quickly, its log, if it drops off slowly then quickly at the end, its anti-log.  Most almost certainly a volume pot is a log so just confirm that it isn't linear.