Re: Fluke 289 multimeter not working
I have checked some voltages on the board.
I noticed that the 5V after U17 (5V LDO) is present only for 18,6msec after startup.
See attachement with plot of output U17 after turning on multimeter.
After startup the enable pin of U17 is made low for only 18,6msec by the MCU M340F. So most of the time the 5V is 0,7V instead of 5V (TP3).
The 32kHz is present on xtal near M430F. Another board voltage is 3,046V, for example on C42.
I don't see debug information on TX of J5. Should it present when turning on multimeter?...
Pauldg1
Member
Last Activity: 04-12-2021, 12:37 PM
Joined: 04-05-2021
Location: Moerdijk
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Re: Fluke 289 multimeter not working
Thanks,
I will check Q22 and power supply voltages.
And I will try to access debug console
with ExtraPuTTY (if MCU is working).Last edited by Pauldg1; 04-09-2021, 01:09 PM.Leave a comment:
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Re: Fluke 289 multimeter not working
I have an update below:
- The current consumption is 68mA @9vdc with LCD.
- The current consumption is 24mA @9vdc without LCD.
See thermal image attached:
Left picture (SAT24):
- Included LCD
- Ambient 16 deg
- Q22 28deg
- U20 22deg
- U21 23deg
Middle picture (SAT26):
- Excluded LCD
- Ambient 16 deg
- Q22 30deg
- U20 23deg
- U21 17deg
Right picture (SAT31):
- LCD bottom side
- Ambient 16 deg...Last edited by Pauldg1; 04-07-2021, 01:33 PM.Leave a comment:
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Re: Fluke 289 multimeter not working
9V * 68mA = 0.612W should be visible by ir thermal camera. I will check this.
What is the communication protocol over the tx debug?
Which software tool do I need to translate the received packets?...Leave a comment:
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Re: Fluke 289 multimeter not working
The current consumption is 68mA @9vdc with and without supercap....Leave a comment:
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Re: Fluke 289 multimeter not working
Tantalum C51 is not burnt. It touches the battery lips in the bottom cover exactly on that point (design flaw). I have seen same picture of c51 on the web of another Fluke 289....Last edited by Pauldg1; 04-05-2021, 01:59 PM.Leave a comment:
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Re: Fluke 289 multimeter not working
That's useful information!
- I will measure and share input current @vbat with super cap.
- I will measure and share input current @vbat without super cap.
It would be great if I can catch debug information.
Can I receive that on my laptop if I build an rs232 to usb converter between fluke and laptop? E.g. FTDI FT232 chip?
And do I need a software tool?Last edited by Pauldg1; 04-05-2021, 02:42 PM.Leave a comment:
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Re: Fluke 289 multimeter not working
Yes, I have noticed that also.
It should not have significant impact on the inductance.
However as you mention it say something how
care the meter is handled by someone.
By the way, the rest of the pcba looks very good, no rework etc.
So want to focus on what is the cause of the symptons, could the bad super cap cause the symptoms?...Leave a comment:
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Re: Fluke 289 multimeter not working
It seems not the lcd because nothing is working well.
- The green led turns not off after startup.
- No beeps in diode mode or when backlight is tried to turned on
- Nothing is working well.
The backup super cap seems bad, but has not leaked to the pcb. See zoomed photo.
Does a bad super cap gives the symptoms I have?
Is it solved by only replacing the cap (and cleaning the pcb)?
The warranty is expired (pcb from 2005), and I have no purchase receipt.
Thanks for the ...Leave a comment:
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Fluke 289 multimeter not working
I have a Fluke 289 multimeter which does not work.
Have anyone an idea what could be the cause?
When I turn on the device only the green led is continuously on, and strange stripes are present in lcd screen. I can only turn off the device by removing the batteries.
Any suggestions will be appreciated... -
Re: New Members - please post your introductions here
Hello,
Hereby I will introduce myself. In my daily work I am an electrical hardware engineer, developing embedded electronics, lighting electronics etc. From idea, to schematic, to pcb layout, to test/measure to optimize electrically and also optimize emc emission and immunity and safety.
The reason I join this forum is to help and to get help in electronic issues we are dealing with. Now (actual issue) for example I have purchased a lot of Fluke damaged multimeters from a person who stops with his hobby....Leave a comment:
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