I think MFJ is really an electronics study course in disguise. Nearly 50% of their devices have problems due to quality control issues. The ham has to deconstruct, diagnose and repair and in the end gets a formal education on repair skills. A real bonus. LOL 73 Stefan, looking forward to part 3.
Hello Stefan - That was an annoying result for you. I hope you will discover the problem soon. There is nothing worse than working on a scrappily designed and unrepairable item. Hoping you will have success in part 3 of your video.
I was shocked when the new PIC controller did not fix the problem! (Bet you were too 😮) As the display and its controller seem to be working I would look for a buffer chip between the PIC and display (plus associated circuitry of course) and any addressing lines. Regards, David
Did you check the wakeup signal going into the PIC? Since that is derived from the freq input, it may be somehow alerting the PIC to the fact that there is a frequency to measure. Probably it should be high with nothing fed in, and then pulse low, or maybe just sit low with a signal fed in. The pullup is inside the PIC, and is around 10K ohms on port B, if enabled in the firmware.
It seems that both design and manufacturing aren’t at the top. Different story the German dealer’s support…super. This kind of things fight us, but sooner or later we’ll win. Keep going, it’s an interesting fault. 👍
I think MFJ is really an electronics study course in disguise. Nearly 50% of their devices have problems due to quality control issues. The ham has to deconstruct, diagnose and repair and in the end gets a formal education on repair skills. A real bonus. LOL 73 Stefan, looking forward to part 3.
Hello Stefan - That was an annoying result for you. I hope you will discover the problem soon. There is nothing worse than working on a scrappily designed and unrepairable item. Hoping you will have success in part 3 of your video.
Keep your fingers crossed....dear Gerald
Always interested to see your thought processes involved in troubleshooting problems. I really enjoy your channel.
Tnx!
I was shocked when the new PIC controller did not fix the problem! (Bet you were too 😮) As the display and its controller seem to be working I would look for a buffer chip between the PIC and display (plus associated circuitry of course) and any addressing lines. Regards, David
Wasn´t shocked because i always assume the worst case and will be happy, f it doesn´t happen ... hihi.
Yes! I´ve seen that there is a controller on the display board. Will look for a replacement now.
Did you check the wakeup signal going into the PIC? Since that is derived from the freq input, it may be somehow alerting the PIC to the fact that there is a frequency to measure. Probably it should be high with nothing fed in, and then pulse low, or maybe just sit low with a signal fed in. The pullup is inside the PIC, and is around 10K ohms on port B, if enabled in the firmware.
Tnx, i checked the wakeup signal! Its OK.
It seems that both design and manufacturing aren’t at the top. Different story the German dealer’s support…super.
This kind of things fight us, but sooner or later we’ll win. Keep going, it’s an interesting fault. 👍
Компания mfj закрылась . Не будет новых изделий. Не будет брака.