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Post by saltyseadog on Jan 20, 2023 13:28:41 GMT -5
I have had a Boss FBM1 pedal for a few years now but although the pedal still works fine sonically, everytime I rotate the guitars volume knob I get a crackly sound like a dirty pot but only when I move the control. It isn't a dirty pot on my guitars as they work fine with the FBM removed from the circuit. I think it happened when I accidently sent a dc overload into it. Like I say the pedal works okay but the scratchy sound annoys me and I would like to get it fixed if possible.
I opened the pedal today and using a magnifying glass can see that either a resistor or capacitor named L1 on the board is blown. I have tried today to search and download a schematic for the FBM1 without success, I did find a post on Google saying that you can't get a schematic for it due to it being COSM technology. Thought I would try and contact Boss UK but the pedal is out of production and all I can get is the owners manual which I already have. Anyone have any idea of what the L1 would be?.
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jan 20, 2023 15:01:59 GMT -5
L usually indicates an inductor.
Typically they’re used to filter out RF.
Might be used on power supply input, signal input , signal output.
They’re almost alway used with digital stuff, as they tend to radiate their clock signal.
A photo or 2 of the board and close up of the part would be handy. Upload to a free hosting site eg imgbb and supply a link, preferably bb code.
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Post by reverendrob on Jan 20, 2023 20:08:53 GMT -5
COSM is software. It doesn't have a "resistor" in the programming.
Chances are the ground etc is iffy or the filtering as mentioned is toast.
You're not going to find a schematic with said thing.
By the time it's all said and done I'd consider just bagging another one of the pedals - you're going to run up as much shop time getting it looked at by Roland authorized techs (or anyone who knows the things) as they cost.
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Post by Pinetree on Jan 21, 2023 10:15:37 GMT -5
I'm curious.. did you get a solution from any of the forums that you posted this same question to?
Personally, I'd buy another pedal and be done with it.
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Post by saltyseadog on Jan 21, 2023 12:30:44 GMT -5
I'm curious.. did you get a solution from any of the forums that you posted this same question to? Personally, I'd buy another pedal and be done with it. None other than one guy who said that as it is COSM technology you can't get a schematic for it, apparently it is digital and not analogue whatever that means. The parts inside on the board are really tiny, I needed a good magnifying glass to see where the L1 inductor or whatsit had blown. I can't really get another one as it has been discontinued for a couple or more years now. Apparently it has become popular again for some reason or other. Thinking about buying another one as well I was checking out prices on Ebay and used ones were going for between £180 - £300. It is a great little amp in a box pedal with a really authentic 50's tweed overdrive I emailed Roland Boss UK last night asking if it was possible to send it back for repair. Got a confirmation email today with a note that they will respond within 48hrs excluding weekends, so maybe get a reply on Monday or Tuesday. |
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Ayns
Wholenote
Posts: 767
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Post by Ayns on Jan 21, 2023 16:57:04 GMT -5
Wow. I remember when stores were kicking these out new for about £60. (I think they were about £120 rrp).
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