First I want to apologize for my bad English.I have a problem adjusting the volume of my cassette recorder Audi Concert M4 AUZ1Z3. I found on the web some schematics and files for creating a device with a PIC16F84A that can circumvent the motorola MC68HC05. But it does not work and I dont know why.I will attach the file, can someone please help me make it work....