MXR MC-402 no boost

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phantombox
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Joined: 05 Jul 2011, 03:23

Post by phantombox »

Hi guys.
A friend of mine gave me this MXR MC-402 boost distortion pedal. When I press the BOOST switch the pedal goes death silent. Blue LED comes on but no sound. When I press it again the LED goes out and sound comes back. I checked the footswitch and it works all right. There is a transistor (Q8 on the PCB, J177 I believe) which checked continuity between drain and source when in the circuit but was OK once I took it out. Also there is this IC TLC2262 which tests suspicious while in the circuit... I haven´t taken it out jet because with this type of circuit assembly, experience tells me that this is a pita.

Any thoughts?

Thanks in advance
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phantombox
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Post by phantombox »

The J177 is Q10, not Q8. I don't know if the fact that there is continuity between drain and source without power applied to the circuit is correct or not, since there is no schematic for this pedal available anywhere.
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karul
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Post by karul »

phantombox wrote: ↑14 Mar 2023, 17:49...since there is no schematic for this pedal available anywhere.
If you've just scrolled down this page, you would have seen the SIMILAR TOPICS, and the first one on that list is ->
viewtopic.php?t=10060

also there is a search bar. try it next time you are looking for an info
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