In particular, unless you have contacted 4QD about your own situation you may not even have any way of knowing whether it applies to your controller or not. Do not undertake modifications or repairs unless you are sure you are competent to do them and fully understand the instructions. Be warned also that 4QD will not be held responsible for any damage you do whilst attempting to repair or modify your controller or as a consequence of your attempts at modification. We are now selling replacement controllers for these madly made copies. However the main reason is that repairing high current controllers is a very specialist business.
Few people have the required expertise.
Also modern electronics are very reliable. With many thousands of controllers in the field, we do not even run to a proper service department ourselves as returns are few - and most of those are not faulty. We also modify controllers frequently if we find any pattern of failures, in order to 'customer-proof our designs. So, if you do need circuits, ask, but please tell us why you need them and why you consider yourself knowledgable enough to make proper use of them. See the various 'Modification history' pages here.