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Replacement for Ibanez volume pot marked 1B100?

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  • #16
    Originally posted by J M Fahey View Post
    I think I can reasonably confirm itīs indeed 100k , just marked in a unique "Ibanez way".

    Weird, so far could NOT find the schematic, which normally is the first Tech data available for anything, while I found various instances of its parts list, which generally is not available, unless itīs a detailed service manual

    Said parts list does not fully clear it about mystery volume pot but we can compare its description to other pots (treble, bass, etc.), although all pots are called "volume pot".

    * VR101 32S00265 VRRE1ECPB10A VOLUME POT B10K
    * VR103,105 32S00522 VRRE1ECPW20C VOLUME POT W20K
    * VR102,104 32S00390 VRRE1ECPB50C VOLUME POT B50K

    Now it gets slightly more twisted: they seem to have reserved the last 3 characters (2 numbers + 1 letter) in the VRRE string to indicate value in k.
    But what values above 99k, which need four characters? (3 numbers + 1 letter)
    I guess they drop the first one but print the string twice, the second one showing the full numerical value:

    * VR106 32S01749 VRRE1ECPK00A VOLUME POT 1B100
    Which I read as: 3 character code: 00A (should say 100A but no space reserved for first "1" digit) so they clear it by printing in a second string "B100" .
    They "should" then print an third string specifically stating 100k, like the ones above, but probably their Excel page or whatever this software is based on, does not include the extra column needed.

    Thatīs the only logic "explanation" I can find.

    Can add the educated guess that 100k is a reasonable value for a volume pot plus the successful experiment of using b100k there.

    Why would Ibanez print such weird label, even on pot itself?
    Maybe Ibanez is using some old inventory control software, long on the tooth by now, but are stuck to it because itīs been used in thousands or previous products for decades.

    Just an educated guess,of course.
    All the other pots were labeled in a conventional fashion. Just this one oddball. I wonder if Ibanez even used it in many other places, since most Ibanez products I can think of (guitars and effects) wouldn't use a regular straight leg PCB mount pot.

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    • #17
      Originally posted by J M Fahey View Post
      I think I can reasonably confirm itīs indeed 100k , just marked in a unique "Ibanez way".
      But he measured the track in the old (original) one as 100 ohms.
      Originally posted by Enzo
      I have a sign in my shop that says, "Never think up reasons not to check something."


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      • #18
        Maybe they had to use a conventional over the counter part in this design, for whatever reason (space? ... availability? ...) instead of their usual custom ordered by the millions ones, and just to make it difficult for the end user they labelled it in a cryptic way.
        At least anybody asking Mouser or any other supplier for a "1B100ohm" pot will either get a deer in the headlights look or a useless 100 ohm pot, and be forced to go through Authorized Service.

        Or they can plausibly deny: "no, our $7 + shipping 1B100 pot is NOT the same as an 80 cent B100K pot which you probably have in your parts drawer"

        Just being a little paranoid he he.
        Juan Manuel Fahey

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        • #19
          Update to this old thread. This amp seemed to be working OK with a 100k ohm volume pot, though it was WAY off from the original. My kid was using it for a while, sounded fine, then went to use it one day and it was very noisy. Opened it up to take a look and noise went away. Loaned it to a friend who said it sounded a bit fuzzy. Got it back and noticed that it was picking up AM radio when you turned the volume knob to a certain point. Probed the speaker output and there was a large signal up over 100kHz on the speaker output. It seems like having too high a pot value can cause some issues. I found a 1k pot and installed that and it seems to be working very well now.

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