Author Topic: Fluke 289 - Switches on, showing —— on display, system menu ok  (Read 693 times)

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Offline albokid

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I have a Fluke 289 meter that until recently was working ok.
Now when I switch it on the display only shows a row of dashes where the numbers should be.
I can still access the system menu, change date, reset unit etc
I have contacted Fluke and they would repair it under the lifetime warranty, only issue with that is I was using it for long term monitoring which involving connecting a D.C. supply in place of the batteries. Regret putting the hole in the back now for that wiring. (Although even if the hole wasn’t there it has battery leakage damage which has corroded most of the battery terminals.) I’m aware I could get a replacement back and I might go down that road but would want to try getting the meter working first.
I have checked the circuit board for any damage and there is none present. Not sure what’s causing it, but when I measure the current drawn by the meter it was averaging 145mA which looking at other posts is at least 5 times what it should be.
It is surprising it had stopped working as it was not being used for any high voltage testing, it was connected to a fire alarm sensor which are nominally 24v. I recall disconnecting it from that wiring to check the voltages relative to earth at which point the meter display dimmed. After trying this measurement relative to earth a couple of times the meter stopped working correctly, initially I remembered it still having some functionality where dc voltage would show readings but then deteriorated to only showing the dashes.

Appreciate any help others can provide, photos can be taken on request

Stuart
« Last Edit: May 28, 2018, 11:10:32 am by albokid »
 

Offline retiredcaps

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Re: Fluke 289 - Switches on, showing —— on display, system menu ok
« Reply #1 on: May 29, 2018, 03:59:55 am »
but when I measure the current drawn by the meter it was averaging 145mA
What is the current consumption when the meter is turned off?
 

Offline albokid

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Fluke 289 - Switches on, showing —— on display, system menu ok
« Reply #2 on: May 29, 2018, 07:00:33 am »
but when I measure the current drawn by the meter it was averaging 145mA
What is the current consumption when the meter is turned off?


The current is nominally 0mA with the meter turned off (there was a short pulse to 1.5mA). I measured the in use current again and it was 208 mA, not sure why it has changed other possibly than the method I am using to power it. (9v dc from usb step up adaptor, previously it was a 9v psu I was using when I was running the long term monitoring). The current increased by around 10mA on each press of the backlight button.

I have carried out further operational checks, the meter recognises if the leads are in the wrong positions for the selected function. When on the resistance measurement and the range is manually changed to 500 or 5000 ohms there is a static level showing on the analogue bar but doesn’t track as shows 250 on 500 and 3000 on 5000 scale, still no numerical data though on any function though.
« Last Edit: May 29, 2018, 07:23:25 am by albokid »
 

Offline ModemHead

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Re: Fluke 289 - Switches on, showing —— on display, system menu ok
« Reply #3 on: May 29, 2018, 08:46:50 pm »
Nominal current draw for my 289 is 24mA in VDC mode.  Backlight off.  It peaks at about 50mA on boot-up.

Most Fluke models use a microprocessor that is separate from the analog subsystem.  It's been my experience that when the uP is running ok, but cannot communicate with the analog section, it will display "----".  As you can imagine, there can be all kinds of faults that could cause that.

If it's drawing 208mA, something is probably getting hot.  Got any IR equipment?
 

Offline albokid

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Re: Fluke 289 - Switches on, showing —— on display, system menu ok
« Reply #4 on: May 30, 2018, 10:08:44 pm »
Nominal current draw for my 289 is 24mA in VDC

If it's drawing 208mA, something is probably getting hot.  Got any IR equipment?

I will see what I can do investigating the possible hot component and report back.
 


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