Yes, I had one before I got one of Bills Pickit 2 style programmers. While I was using the JDM I thought pic programming was insanely complicated because programming seemed to fail or work for all kinds of reasons. Eventually I realized that it was figity and would sometimes fail for no real reason at all.
Sometimes the JDM programmer "locks up" a PIC chip such as 16F628 and it cannot be programmed again.
You need to re-program it on a different type of programmer to be able to re-program it.
I don't know if the Velleman classes as a JDM programmer, but here goes;
I added a wire from both ends of D7 on the circuit board to a switch.
By shorting out 'D7' BEFORE putting the K8048 into program mode allows one to erase the 16F628 ( in my case ).
I learned this trick from reading about people whom had problems with the OSCAL value of the 16F675. ( Like me )
Sometimes the JDM programmer "locks up" a PIC chip such as 16F628 and it cannot be programmed again.
You need to re-program it on a different type of programmer to be able to re-program it.