Thanks to Shuey who sent me two damaged SmartTire sensors for detailed surgical analysis, to determine if the batteries can be replaced (as we know, we can no longer buy new sensors).
The photos show the sensors with a black silicone type filling material, that is quite spongy and can be picked off easily. Next pic shows potting material off, two screws exposed and the red lines indicate 4 solder points of the battery connections to the circuit board. I cut around the board with a knife to cut as much potting material as possible, to make circuit board removal easier. Next, to pry the board up carefully, one end was stuck down (batteries soldered to board but potting material around them). Notice a copper spring, which I think may be the antenna. Once apart, I found a piece of wire, which looks like it broke from the coil, and one end was inserted into the board (I attempted to recreate the original).
I do not know if the copper antenna spring was broken before I disassembled or not, but let us strongly suspect I broke it when I pried the board upwards. It is held by a three-pronged triangle of tabs, but may have been "glued down" by potting material.
Next, on to the batteries shown covered in potting material, which strained as I pried more. No real damage except to separate the two button batteries (Panasonic 3 volt, #BR1632A), which have a contact wire projection welded to each surface, an insulating washer in between the two, a green heat shrunk insulator around each battery. The wires go through the board and are soldered on the opposite side. They are in parallel, not series, so the board runs on 3V. Shuey, I did check these batteries and they appeared to have 2.4V each remaining. Date code stamped on the assembly was 3Y08, whatever that means.
Next pictures show one leg unsoldered from the board, and I opened the sandwich.........
My conclusion, not replaceable by the ordinary guy who likely doesn't have a mini-projection welder and spare terminals. Further, one probably should use some kind of silicone solvent to break down the potting material, but I would be suspicious that it might damage the componentry. As well, I was working on a broken sensor where plastic was broken away allowing me better access than an unbroken sensor....... yes, I saved the other one if anyone thinks this is worth pursuing.
And if we can't replace these batteries or knows someone who can, we are doomed to replace a great TPM system IMHO, with another.
So, be careful not to break the sensors when dismounting tires, break the bead 90 degrees to the sensor and work around carefully. From new, SmartTire claimed a 7 year battery life, for what that's worth.
Once again, thanks to Shuey. I hope this is useful to those of us with SmartTire systems.
The photos show the sensors with a black silicone type filling material, that is quite spongy and can be picked off easily. Next pic shows potting material off, two screws exposed and the red lines indicate 4 solder points of the battery connections to the circuit board. I cut around the board with a knife to cut as much potting material as possible, to make circuit board removal easier. Next, to pry the board up carefully, one end was stuck down (batteries soldered to board but potting material around them). Notice a copper spring, which I think may be the antenna. Once apart, I found a piece of wire, which looks like it broke from the coil, and one end was inserted into the board (I attempted to recreate the original).
I do not know if the copper antenna spring was broken before I disassembled or not, but let us strongly suspect I broke it when I pried the board upwards. It is held by a three-pronged triangle of tabs, but may have been "glued down" by potting material.
Next, on to the batteries shown covered in potting material, which strained as I pried more. No real damage except to separate the two button batteries (Panasonic 3 volt, #BR1632A), which have a contact wire projection welded to each surface, an insulating washer in between the two, a green heat shrunk insulator around each battery. The wires go through the board and are soldered on the opposite side. They are in parallel, not series, so the board runs on 3V. Shuey, I did check these batteries and they appeared to have 2.4V each remaining. Date code stamped on the assembly was 3Y08, whatever that means.
Next pictures show one leg unsoldered from the board, and I opened the sandwich.........
My conclusion, not replaceable by the ordinary guy who likely doesn't have a mini-projection welder and spare terminals. Further, one probably should use some kind of silicone solvent to break down the potting material, but I would be suspicious that it might damage the componentry. As well, I was working on a broken sensor where plastic was broken away allowing me better access than an unbroken sensor....... yes, I saved the other one if anyone thinks this is worth pursuing.
And if we can't replace these batteries or knows someone who can, we are doomed to replace a great TPM system IMHO, with another.
So, be careful not to break the sensors when dismounting tires, break the bead 90 degrees to the sensor and work around carefully. From new, SmartTire claimed a 7 year battery life, for what that's worth.
Once again, thanks to Shuey. I hope this is useful to those of us with SmartTire systems.
