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i need a schematic of fluke 179 or something like that. my fluke turned on 179 - - - -.i don't know of any faulty parts that could cause this
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Hi Doan,
Are you saying your Fluke 179 will not turn on?
Or are you saying it will turn on but no display?
Or what are you reporting is the problem exactly? I can tell you that there are very few active parts on that meter. If the main chip is OK (which you can determine after a successful power-on by observing the display for the 179 Splash Screen) then it is easy to repair. You can check all the active devices with a meter in situ (Diodes, BJT, FET, voltage regulators), and if you have the inclination, you may replace the LTC2435 24Bit Sigma-Delta Analog to Digital Converter, although I bet there is nothing wrong with it.
See the parts list I posted above, as well as the other URL I referenced, for the details on the active devices on the PCB of the 179
In my experience the problem was with the power control MOSFET and associated BJT.
MOSFET Q7 IRLML6302 and BJT Q5 MMBT6419. (Note that there are no component designations on the PCB, but I posted a photo above to help with identification)
I suspect the power-on circuit cannot defend itself against battery polarity error. Which, if true, is pretty appalling. Looking at YOU FLUKE!
Regarding a schematic...if you ever find one, let us all know!