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Pot Question, HELP!

Discussion in 'Amps and Cabs [BG]' started by jondog, Aug 12, 2004.


  1. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    I bought a piece of gear that was damaged in shipping. It's inexpensive enough that it's not really worth going through the hassle of a UPS claim, so I want to try and repair it myself. I need to replace 2 pots that got broken off of the circuit board when it was dropped. It looks like I should just be able to desolder the remains of the old pots and resolder new ones in, pretty easy. They say 15A10K on them, and then 9328. The Radio Shack guy agreed w/ me that 10K is 10 kilo-ohms, what is the 15A for? Amperage? He has audio taper 10K audio taper pots in stock, is this what I need replace the limiter threshold and sub master level knobs in my new/used/beat Furman Punch 10? Thanks, Jon :help:
     
  2. jondog

    jondog

    Mar 14, 2002
    NYC metro area
  3. Passinwind

    Passinwind I Know Nothing Supporting Member

    Nope, that's the audio taper signifier. Look here: http://www.sound.westhost.com/pots.htm#markings
     
  4. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    I got all excited when I saw "Pot Question" [​IMG]
     
  5. Unless I overlooked something I didn't see any pots on that schematic. Do you have page 8?

    You've got a 10K audio taper, but there's a couple of different styles and I believe that's what the 15 is. It certainly isn't 15 amps. I'd sub a regular 10K audio taper, but instead of Radio Shack, do you have a REAL electronics parts store handy? If so, take one of the pots in there and they'll match it with the exact same shaft size (important!! who wants to change knobs)
     
  6. Passinwind

    Passinwind I Know Nothing Supporting Member

    Might be 15% taper, or 15mm shaft, but it's almost certainly not a 15 amp pot.
     
  7. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Thanks, you guys are great! Here's page 8

    http://www.furmansound.com/pdfdata/DJM-8/8.pdf

    but it says it's for main eq board? Pg. 9 said it was for Sub-Harmonic Processor, but I can't guarantee it's even for this model, the PCH10 is not in current production.

    Anyway, it's good to know I need Audio Taper. I don't know of a real electronics store nearby, RS is right up the street from me. Shaft length isn't very important because the pots are mounted right next to the faceplate.

    edit - oh, you mean shaft width! I don't really care if my knobs are mismatched.
     
  8. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Looking again, those are pretty definitely the wrong schematics. Their for parts of a DJM-8, whatever that is.
     
  9. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    OK Nashvillebill was right. :)

    I just got back from the Shack. Their pots are HUGE. Twice the size of the ones I'm replacing and the shaft is about 2.5" long. I could cut the shaft, and the back part *might* fit above the circuit board, but the threaded bit is also too big to fit through the faceplate, so I'd have to drill it out. They also feel kind of cheap (slightly rough turn) and the stats on the package say +/- 20% tolerance, that seems like a lot! These are just too much work so I guess tomorrow I'll hunt down a REAL electronics store. I should've listened . . . :meh:
     
  10. This page could still apply, there's a link to the subprocessor on page 9. Many schematics will cover several pages.

    I see several 100K tone pots, plus a couple of 10K pots. Check both your pots to make sure they're both 10K.

    Good luck! You could also try mouser www.mouser.com but it's hard to browse for parts online. In this case a text catalog is easier to go through.

    PS Yeah, the Ratshack pots do feel pretty chintzy. The % tolerance doesn't matter in this application, it's a variable resistor anyway....I'd go for a better brand.
     
  11. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    I see two 10K pots on that page. One's a trimpot, according to the adjacent text, and the other says 10KB, which would be a linear taper pot. Are they Alps pots?
     
  12. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Yes, they're both 15A10K.

    I don't know what Alps pots are Bob. :(

    I'm pretty sure the schematics are for a different Furman unit. I got those links at the bottom of this page

    http://www.furmansound.com/techcorner1.htm

    and jumped on pg. 9 because it said Subharmonic Processor, which is what the Punch 10 is. But, now that I've looked at it again, I'm pretty sure the DJM-8 included a subharmonic processor along with a lot of other circuits, thus requiring 12 pages of schematics.

    I'll bring the pots I'm replacing to the real electronics store when I find it tomorrow.
     
  13. "Alps" is a brand name, they make pots and switches.
     
  14. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Thanks, I don't know what brand they are. On the back there is a T and an S inside of a circle.
     
  15. notanaggie

    notanaggie Guest

    Sep 30, 2003
    the 10K is just that, 10,000 ohms.

    The 15A means it is a clockwise audio taper, with 15% of resistance at 50% rotation, measured between ccw pin and wiper.

    9328 means they were made in 1993, week 28.

    No pic, so I am guessing, but from the age I'll bet they are round and a little under 3/4 inch diameter (16mm).

    Mouser electronics probably has them, or something that will work.
     
  16. +1 :D
     
  17. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Perfect, thanks!
     
  18. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Mission accomplished! :bassist: Thanks for your help everyone, the unit is now working. It'll be a few days before I can try it w/ my full rig, but based on preliminary tests I think it will work better for me than my dbx 120xp did. I hope nobody ever looks in there to see my crappy soldering job. After I finished, I figured out I should've "flown" the pots by using wires to connect them to the circuit board instead of repeating their questionable design and soldering directly to the board. If it takes another big hit I just might have the opportunity to do that . . .
     
  19. Great, glad you got her working!

    Soldering is an art, a good soldering iron helps. Desoldering braid is the secret to getting the old solder off.