MXR Repair – Carbon Copy

This poorly delay pedal repair had the same problem as this MXR repair job from last year. This is a known ESD fault with Carbon copy delay pedals ‘of a certain age’.

As you can see on the photo, this Delay pedal uses surface mount technology (SMT). This can be a little fiddly to repair, but I often prefer it to through hole!

The faulty items are JFETs Q10-13 (the little 3 pin triangles. As you can see I’ve fitted a tiny Transient suppressor between two legs of the replaced JFETs. This should guard against recurrences of the same problem.

I’ll take another moment to thank the guys at MXR/Dunlop (partic. Derek Jones) who provided excellent tech support the first time I came across this issue.

The owner of this pedal plays harmonica through it with the Whitefern Mountain String Band. If you’re passing through South Wales, then check them out!

UPDATE: 2017

The MXR ESD repair kit is now available for sale at If you’re an experienced repairer and skilled with SMT repairs then you can purchase this kit. If in doubt, just post it to me and I’ll sort it for you.

If you have a delay pedal repair or a Carbon Copy Repair please get in touch.