MXR Flanger 117 Repair?

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2guests
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MXR Flanger 117 Repair?

Post by 2guests » Sat Jun 02, 2018 7:45 pm

So, I'm going through pedals I haven't used in several years or more...my old MXR Flanger's speed function no longer works. It sounds like it's on an EH flanger's Filter Matrix mode. There is flange. The manual, width, and regen knobs all work but there is no movement through the flange range. I measured the pot and it does work correctly. Anybody have an idea on how to fix this or, better yet, someone that has the ability to fix this? Thanks.
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Scruffie
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Re: MXR Flanger 117 Repair?

Post by Scruffie » Sun Jun 03, 2018 10:08 am

From your description the LFO has stopped running, possible causes would be one or both of the 15uF tantalums in the LFO have gone dry (they don't like sitting unused for a long time) the Opamp itself has gone bad or there's just a bad solder joint.

You can measure the voltages on the Opamp to confirm it's dead, should be the one in the middle of the board.
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jetofuj
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Re: MXR Flanger 117 Repair?

Post by jetofuj » Wed Sep 19, 2018 1:03 pm

Do you know if it is easy to make M117 true bypass? Is it only a matter of new switch and rewiring, or it needs trace cutting and parts' removal?
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Re: MXR Flanger 117 Repair?

Post by Scruffie » Sun Sep 23, 2018 11:27 am

As long as you're referring to the vintage model rather than the reissue it's very simple.

Stock, the foot switch is hardwired to the output jack and switches between the input jack and circuit output so you just need to find out if the input jack has two wires (one to the footswitch and one to the circuit board) which makes life a little easier or one wire (straight to the circuit board and the circuit board has another wire connecting to the foot switch) and then use a standard true bypass wiring scheme, no cuts or removals required. It'll need either a Carlin or Alpha style foot switch as it doesn't look like a 3PDT will fit in the board cut out.

It might require the addition of an input pull down resistor after the mod but that could easily be tacked on the back of the board.
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jetofuj
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Re: MXR Flanger 117 Repair?

Post by jetofuj » Sun Sep 23, 2018 2:56 pm

Thank you very much! I will probably be getting vintage one soon, as I'm on flange kick lately :bong2:
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