| Electronics > Repair |
| Fluke 289 not quite sorted. |
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| MihaiV:
Hi YetAnotherTechie, Agreed, it is a sudden shutdown and it always displays another line, wherever it happens to be when power goes out. I am curious if the two lines that are always low (pin 15 and 17) are driven somehow in a functional meter. The scope shows that the clock signal is continuously going. But what you said points out that is is not necessarily writing only 1s and it might not be a single line that scans from top to bottom like crazy. I will return with a 4 channel oscilloscope to check more signals at the same time. But the fact that the MSP does not enable the 5V rail indicates that the MXS is still not operating properly and the application is not correctly running. MSP might expect a specific message on the SPI from the MXS. |
| MihaiV:
Good evening, I did replace the crystal on the MXS chip, as it showed no signal on one of its pins. I could only see the driving signal from the IC. The new one does resonate with fairly high amplitude but I have a doubt concerning the driving part. Pictures 3 and 4 are the scope captures of each MXS crystal pins. Is this how it's supposed to look? Pictures 1 and 2 are coming from the each of the MSP crystal pins and the driver looks different. The driving signal does have a DC offset, so it can do a complete sinusoid (or close to it). Could the crystal driving part be faulty or the driver in here simply does not need a full sinusoid swing and it does not use a DC offset for it? While at it, I also captured a the brief moment in which the 5V analog power rail is enabled (picture 5). This happens immediately after pressing the power button, way before the logo on the display vanishes, so it does not appear to be related to the MXS not running its application. Does anyone know if MSP checks something during this sequence, or measures something and that is not right (and shuts down the power) ? Thanks, MihaiV. |
| bdunham7:
I don't mean to interrupt anyone's repair, but since the topic is not quite sorted F289s, can anyone tell me how long the memory/date/time should be retained by the supercap with the batteries removed? Fluke's online tech support seems to be suffering and their rep couldn't answer questions with anything but nonsense. Mine is v1.16, had the supercap serviced by Fluke last year and loses the memory in less time than it takes me to charge the Eneloops that I use in it. It works fine otherwise and doesn't drain the batteries unreasonably. |
| alex_hobeanu:
I removed the batteries on mine for 24 hours and found the date / time to be correct after I put them back and power up the meter. I have no data stored in the meter but the rtc ran fine so I guess there was enough energy stored internally to keep the memory alive. Fluke 289 serial # 41840060 (March 2018), firmware version 1.16 / V0.88. |
| bdunham7:
--- Quote from: alex_hobeanu on June 08, 2021, 07:28:39 am ---I removed the batteries on mine for 24 hours and found the date / time to be correct after I put them back and power up the meter. I have no data stored in the meter but the rtc ran fine so I guess there was enough energy stored internally to keep the memory alive. Fluke 289 serial # 41840060 (March 2018), firmware version 1.16 / V0.88. --- End quote --- Thank you for checking that. Mine is older, 2011 or so, but AFAIK, there are only two versions and yours is the same FW level as mine, so it is the 'older' version. |
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