Great challenge you’re facing 😊 Dealing with PICs is t something I particularly enjoy, so I stick to tubes 😊 I was hoping the CMOS IC was the issue because at least you can then deal with it simply, but no … that would have been too easy 😊 Good luck 🤞
Stefan- The very large toroids sometimes crack the solder joint during shipping. MFJ did not hotmelt glue them down. So sometimes you'll find these have been resoldered. This won't fix the issue of the vid, but just an FYI. I also found while working on these, is a lot of wave solder flash/splatter all over the board & sometimes that flash will lay on the IC pins.
lots of PICs fail in the MFJ antenna tuner products. They have no shielding and they are close to the power RF parts. If that friend of yours can trick that PIC to be readable (very-very small chance of success but i've seen cases that it could be read in certain conditions - for example higher Vcc could "unlock" them - at least the older versions), then the HEX could be read and transferred to a new PIC. But before that, try to borrow a good PIC and test the tuner with it, to be sure it's working. Since MFJ is out of business, maybe another company is doing their warranty work.
It may be possible to dump the PIC program with a programmer like TL866a. It should be also possible to program a blank PIC with the same device. You need that the devices list include your PIC of course and a TL866a as well. As your PIC is failing, as it seems, only on the counter function, you may be lucky enough to revive it. I wish you will be able to post a successful part 2😁
Guten Tag Stefan. One problem is pic processor have a bit which can be set to prevent the code from being copied. I understand the idea but it makes servicing next to impossible. Living in the US, it was widely announced MFJ was going out of business months ago. I had hoped another interest would buy out the company assets and carry on support but I have no info on any such arrangements yet. It seems your pic may be working since you were able to invoke several options successfully. I'd be very surprised if the pic is the issue, especially since you updated the firmware. Did you happen to notice the original firmware level and the level after the update on the display. As a general rule processors either work 100% or totally dead the VAST MAJORITY of times. Maybe I'm confused but you did show the input signal to the pic was intermittent and other issues like a missing R and a very sloppy installation of the IC next to the PIC. Based on what you shared, I'd replace the R then check function and if no joy, then remove the sloppily installed IC, check the pcb traces in that area and maybe replace that IC. All of these steps should be executed before worrying about the PIC. I will look to see if there is any new news regarding a new owner for MFJ and report any possible news to you. Personally, when I have had people send me projects which were already messed with and messes created by someone else, I send them back. Life is too short to waste precious time on others failures. IMHO. 73, WA4AOS, Glenn
@@dl7majstefan753 FYI, the only news I was able to find regarding MFJ, is the Chinese are possibly going to start selling MFJ look a like's and benefit, stealing, from the intellectual property of MFJ; something they are notorious for. SHAME.
In fact, there is a lot of programmers for PIC microcontrollers, you can also easily build your own (as long as you have a PC with a RS-232 port), but. The main question is if the PIC is locked or not. If it is not locked, then it is easy, just read the firmware from the broken chip and burn it into a new one, but if it is locked, then this is no more an option. I looked at that fimware update tool. I am not familiar with M$ Window$ (in fact, I'd never used that thing), but it looks like it contains strings with something, that looks like a content of an intelhex file, which, in my opinion, is that firmware. I am almost sure that if you find someone who is familiar with Ghidra (or similar tools) and all that Window$ stuff, then it is possible to extract that firmware from the update utility, furthermore, I think this could be relatively easy job.
The main hex stuff doesn't look like intelhex it looks like a custom hex format, the first few bytes are repeated then it looks like an address to program then a separator then the bytes, and finally and end of byte marker.
The PIC has separate protection bits for different areas of the Flash. I would have your friend try to read anything he can from the old chip. If he can get the bootloader, then you can download the hex file for the rest of the firmware. Most likely it's all protected, but there is a small chance they didn't protect everything. If you read the Flash and it's protected, you will get all 0's or all 1's (can't remember). Most USB EPROM programmers can also handle PIC chips. I might try changing that HC14 Schmitt trigger IC, as the soldering looks horrible. The input to the PIC should be a steady square wave, not what you seemed to have, with the longer low time sometimes. Perhaps the PIC doesn't like what it is being fed. Maybe the firmware checks to see if the freq of the input is steady, and rejects it if it's not. Good luck. Another idea would be to remove the HC14 and feed a nice 0-4V square wave into pin 6 IIRC of the PIC, through a 1K resistor just to be extra safe, and see what happens. Keep the frequency low, like 1 MHz, so that the 1K resistor doesn't mess it up too much.
The HC14 can´t be the problem, because this configuration worked and suddenly stopped working. So it is assumed to be the PIC.... We´ll try next week several attempts as described in the comments. Thanks
Best of luck Stefan with finding any help from MFJ *(Manufacturers of Fine Junk)* MFJ are gone out of business some time ago. I prefer my manual tuner/matcher, nothing much ever to go wrong. 73 Stefan
Hopefully your friend will have an answer. I have zero experience with PIC microcontrollers, but as yours seems to be mostly working perhaps it is possible to copy an image of the software from it to the new chip. Regards, David
Great challenge you’re facing 😊 Dealing with PICs is t something I particularly enjoy, so I stick to tubes 😊
I was hoping the CMOS IC was the issue because at least you can then deal with it simply, but no … that would have been too easy 😊 Good luck 🤞
Murphys law!
Stefan- The very large toroids sometimes crack the solder joint during shipping. MFJ did not hotmelt glue them down. So sometimes you'll find these have been resoldered. This won't fix the issue of the vid, but just an FYI. I also found while working on these, is a lot of wave solder flash/splatter all over the board & sometimes that flash will lay on the IC pins.
Tnx dr Homer - known but my actual problem is different
lots of PICs fail in the MFJ antenna tuner products. They have no shielding and they are close to the power RF parts. If that friend of yours can trick that PIC to be readable (very-very small chance of success but i've seen cases that it could be read in certain conditions - for example higher Vcc could "unlock" them - at least the older versions), then the HEX could be read and transferred to a new PIC. But before that, try to borrow a good PIC and test the tuner with it, to be sure it's working. Since MFJ is out of business, maybe another company is doing their warranty work.
Tnx for the hint with Vcc
@@dl7majstefan753 warning, a higher Vcc can also destroy the PIC, so it's a very thin line between success and total loss.
It may be possible to dump the PIC program with a programmer like TL866a. It should be also possible to program a blank PIC with the same device. You need that the devices list include your PIC of course and a TL866a as well.
As your PIC is failing, as it seems, only on the counter function, you may be lucky enough to revive it. I wish you will be able to post a successful part 2😁
Hope also so ...
Good to see you Stefan. I'm looking forward to part 2 of this repair. 73 OM
Tnx
Guten Tag Stefan.
One problem is pic processor have a bit which can be set to prevent the code from being copied. I understand the idea but it makes servicing next to impossible. Living in the US, it was widely announced MFJ was going out of business months ago. I had hoped another interest would buy out the company assets and carry on support but I have no info on any such arrangements yet.
It seems your pic may be working since you were able to invoke several options successfully. I'd be very surprised if the pic is the issue, especially since you updated the firmware. Did you happen to notice the original firmware level and the level after the update on the display.
As a general rule processors either work 100% or totally dead the VAST MAJORITY of times.
Maybe I'm confused but you did show the input signal to the pic was intermittent and other issues like a missing R and a very sloppy installation of the IC next to the PIC. Based on what you shared, I'd replace the R then check function and if no joy, then remove the sloppily installed IC, check the pcb traces in that area and maybe replace that IC. All of these steps should be executed before worrying about the PIC.
I will look to see if there is any new news regarding a new owner for MFJ and report any possible news to you.
Personally, when I have had people send me projects which were already messed with and messes created by someone else, I send them back. Life is too short to waste precious time on others failures. IMHO.
73, WA4AOS, Glenn
Tnx dr Glenn - let´s see what the future will bring in this topic
@@dl7majstefan753 FYI, the only news I was able to find regarding MFJ, is the Chinese are possibly going to start selling MFJ look a like's and benefit, stealing, from the intellectual property of MFJ; something they are notorious for. SHAME.
In fact, there is a lot of programmers for PIC microcontrollers, you can also easily build your own (as long as you have a PC with a RS-232 port), but. The main question is if the PIC is locked or not. If it is not locked, then it is easy, just read the firmware from the broken chip and burn it into a new one, but if it is locked, then this is no more an option. I looked at that fimware update tool. I am not familiar with M$ Window$ (in fact, I'd never used that thing), but it looks like it contains strings with something, that looks like a content of an intelhex file, which, in my opinion, is that firmware. I am almost sure that if you find someone who is familiar with Ghidra (or similar tools) and all that Window$ stuff, then it is possible to extract that firmware from the update utility, furthermore, I think this could be relatively easy job.
Tnx for the hint (Ghidra) - we will try it
The main hex stuff doesn't look like intelhex it looks like a custom hex format, the first few bytes are repeated then it looks like an address to program then a separator then the bytes, and finally and end of byte marker.
I suppose if you did flash the pic, you'd still need to setup the config bits correctly.
@@Ju00Ls Maybe but there is a factory default setting in the menue - i tried it without success
The PIC has separate protection bits for different areas of the Flash. I would have your friend try to read anything he can from the old chip. If he can get the bootloader, then you can download the hex file for the rest of the firmware. Most likely it's all protected, but there is a small chance they didn't protect everything. If you read the Flash and it's protected, you will get all 0's or all 1's (can't remember). Most USB EPROM programmers can also handle PIC chips. I might try changing that HC14 Schmitt trigger IC, as the soldering looks horrible. The input to the PIC should be a steady square wave, not what you seemed to have, with the longer low time sometimes. Perhaps the PIC doesn't like what it is being fed. Maybe the firmware checks to see if the freq of the input is steady, and rejects it if it's not. Good luck. Another idea would be to remove the HC14 and feed a nice 0-4V square wave into pin 6 IIRC of the PIC, through a 1K resistor just to be extra safe, and see what happens. Keep the frequency low, like 1 MHz, so that the 1K resistor doesn't mess it up too much.
The HC14 can´t be the problem, because this configuration worked and suddenly stopped working. So it is assumed to be the PIC....
We´ll try next week several attempts as described in the comments. Thanks
Best of luck Stefan with finding any help from MFJ *(Manufacturers of Fine Junk)* MFJ are gone out of business some time ago. I prefer my manual tuner/matcher, nothing much ever to go wrong. 73 Stefan
Yes, sometimes the manual method is the best....hi. My car also has a manual shift and not an automatic transmission
Hopefully your friend will have an answer. I have zero experience with PIC microcontrollers, but as yours seems to be mostly working perhaps it is possible to copy an image of the software from it to the new chip. Regards, David
Tnx