How to fix TM-902C battery problem / to repair digital thermometer tm-902c switch battery drinking
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- The following is about how to fix a factory design defect of the digital thermometer TM-902c.
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Thanks by watching it! :-)
I just ordered one of these and got is about a month ago. Based on your video I immediately tested it with my Fluke 87 IV and measured the standby current of the TM-902C in the off position. It was in the micro amps draw range. I have left the battery in and there seems to be no issue of excessive battery drainage. I left it as it came from the factory. There must be different versions of this unit out there. Mine seems to be low standby current draw version. Great video and warning to see if there was a potential problem with the one I received. I will let it go as is. Seems like the standby draw is very acceptable for just sitting there and not draining the battery.. I still like your idea of totally disconnecting the battery all together with the switch. I might do that in the future. I don't know why you have a switch and not completely disconnect the battery. Who knows what they are thinking. Thanks again.
Thanks for this modification. But why on earth did you do it this way ?
It can be done much easier without drilling holes in the PCB !
Just remove the switch, shorten the outer pins of the switch to about 2 mm length and solder the black wire from the battery clip to the formerly unused outer pin. This can be done, because there is some space between the underside of the mounted switch and the PCB.
Remount the switch but now turned 180 degrees, so that the center pin of the switch is facing to the edge of the PCB and solder this pin to the ground plane of the PCB. But first remove the paint from the area to be soldered to.
The rest like the bridge wire and fixing the switch with solder remains the same.
I think that this is a much neater way to do this mod.
Hi! There are different clones from the same original model. I did what was easy to me in the clone I got. I saw another from a friend of mine, with the same problem but different PCB. Maybe you are right. I will check some day mine and compare it with your instructions. :-)
Well done! Thanks for pointing out the design flaw!
+SergTTL Hi! Thank you! As we know, somewhere in the planet all the electronic equipment is cloned, no by one, but by several factories who clones one cloned after the other... In one of them, at the end, printed the PCB without part of the drawings. Maybe the first and original thermometer, was well done. But the rest we get in mayor online shops, come with the design error. I hope the actual Asiatic factory, copies the "FREE" idea from this video, and for sale a better product and do not transfer the problem to the final client. (That's the way we think and do in America and Europe). They got a free problem solving. I hope they honor their courage, and do it right after my video.
Very good solution. Anyway, do you know how to calibrate it?
Amazing channel!
I just ordered one that has a red button to turn on. When I get it, I will check the current draw when off. It may not be as easy to fix.
nice. Just a note, I bought one 2019-08, they change the design. Regulator is after the switch. It's the same shape and look. But a logo is different. I am going to replace 9v with an old mobile battery plus charger and microusb port (all together few cents worth) so I checked the regulator, it's HT75XX-1 and it takes 3.1 up to 24 volts by docs (tested). But the device still works at 2.4V and the low battery symbol starts showing at 2.8V. Any idea what pins p4 p5 p20 p21 p22 are? I'd like to add switch to Fahrenheit and additional temp sensor.
Good, I have used this TM902C with a 12 point selector at a distance of 30 meters and the reading comes out wrong, sometimes above 10 degrees and minutes with temperature 10 below the actual temperature. How can I solve this problem?
HOla Bob soy un seguiidor de tus videos..pero por favor En Español....pliissss
And I thought that "Gambiarra" was a Brazilian thing !!!