Fulltone - Fat-Boost FB-1 Rev 2

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ilcaccillo
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Post by ilcaccillo »

Hello I have a Fat-Boost FB-1 - revision 2 (Drive pot with 11steps and tone in the middle),
I bought the pedal knowing that it was not working. Opened it up and there was some fire inside the pedal,
one or more components inside the circuit burned and no remains are left to be seen.
Some of the pcb traces and pads on the area of the burning components were quite affected.

I would like to fix this pedal but I cant get any schematic for it, Contacted Fulltone and the help was not much also.
I need to now what component or components (with value) burned so I can install them and fix this pedal.

I there any chance that any of you has this pedal and could take some pictures of the guts?
this way I would be able to know what components burned and where they are connected. I guess it's either a capacitor or a Diode, or both.

My pedal although is a Rev2 circuit has a Revision 1 board (unit with tone pot on the right nd without 11 steps pot) , I think that when Fulltone changed the circuit they still had quite a big stock of Rev1 pcb's and enclosures and those were used for the Rev2, check how the resistors are soldered together on air.

Once again if you have this pedal please take some pictures
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underside pcb.png
Top PCB.png

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ilcaccillo
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Post by ilcaccillo »

Hello If you have a schematic for the Fulltone Fat Boost FB-1 Revision 2, it's the one with the tone pot in the middle and the 11 steps drive pot, or if you can take some guts pics of PCB and wiring that would be great.

There's a lot of confusion on the web related to Fat Boost Versions, the version I'm referring to is the one attached.
It still uses the same pcb and the FB-1 Rev1 (Copy of the Jack Orman's Mini Booster) but the circuit/schematic/component placement on the PCB was changed when it was discovered it was a copy of Jack Orman's and not an original design.

Mike Fuller about the Rev2 design
"Design/Rumor Note: Rev2 version of the Fatboost is my design. The older (pre 11 position detented knob) version was brought to me as a supposed original design by a former employee (now with another effects company) and turned out to be VERY close to Jack Orman's Mini Booster (which BTW is eerily close to a circuit off of an old National Semiconductor FET application note;) When I was made aware of this in 2003, I immediately revamped/improved the Fatboost, Jack was paid in full for all "pre-detent versions" ever made, and the employee was sent packing. Now you know the real story."


Thank you so much

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ilcaccillo
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Post by ilcaccillo »

I dont know if you can see in the photo, but the 11 step Pot looks like that from the back.
It has some Stripes/Holes.

This circuit is really simple I can actually trace it the only problem is that horrible Solid Gunk that is covering traces and tracks.

How can I take that Gunk out?
If I can clean the board I will trace the circuit
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ilcaccillo
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Post by ilcaccillo »

Hi,
I would like to trace this circuit myself.

can please someone let me know a good method to that the Gunk out of the PCB?

thanks

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Post by ilcaccillo »

can someone please let me know a good method to that the Gunk out of the PCB?

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Post by modman »

I don't know hard to tell. You CAN always attack is with any kind of dissolvent that doesn't hurt the pcb/traces like thinner, acetone, alcohol...
there was one guy once who x-rayed the board to trace it...
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Post by ilcaccillo »

Hi thanks for the tips,
I already tried with thinner and acetone and got no results with it.
The gunk is hard as a rock and still stays solid with the products above

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Post by OnTheTundra »

I am looking for help adding a Treble and Bass control to the Fat Boost circuit to get into the v2/v3 type of circuit. Ive messed around with a couple ideas without much luck. This is obviously a very simple circuit and adding T and B instead of a single tone control shouldn’t be difficult. Maybe someone has a v2 schematic?

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Post by vot »

FatBoostered.gif~original.gif
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Ichabod_Crane
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Post by Ichabod_Crane »

Cool! Is the veroboard layout verified?

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Post by dv8r601 »

Ichabod_Crane wrote:Cool! Is the veroboard layout verified?
I wanna say yes, as I'm 99% sure its the one I used, it is an amazing circuit.Madbean has a pcb transfer for it as well. Paul C has stated on here he redesigned it with a buffer and uploaded a schem for that. look up paulc, you'll see it in his older posts.

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Post by modman »

OnTheTundra wrote:I am looking for help adding a Treble and Bass control to the Fat Boost circuit to get into the v2/v3 type of circuit. Ive messed around with a couple ideas without much luck. This is obviously a very simple circuit and adding T and B instead of a single tone control shouldn’t be difficult. Maybe someone has a v2 schematic?
http://www.freestompboxes.org/viewtopic ... 52&p=26858 this schematic was the basis of what became the Fat boost with tone control. It's been based on Orman's minibooster, the tone control mods by Paul Cochrane, who shared the schematic in the early diystompboxes days, commercialisation by Fulltone :D
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