1. Using your software for JDM PIC Programmer Paki erase yung PIC16F84
2. Check if the PIC is blank using the Software for JDM
If it cannot erase the PIC16F84, something is wrong with your VPP supervoltage,Usually 12V or 13V.
If it can erase the 16F84, and passed the Blank Check, Please read the code memory of the
16F84 and all memory locations should be 0xFF. This will test if your JDM PIC Programmer can reliably read the Program Memory of the 16F84.
You can also try another PIC16F84, maybe the PIC you have used is defective by electrical overstress or ESD.
I hope your JDM Programmer has worked before when you assembled it. If not, please check your circuit or the components you have used.