Fluke 289 multimeter not working

[Pauldg1]

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

[Per Hansson]

Re: Fluke 289 multimeter not working

Looks like the LCD is broken, try to test it in diode mode to light up and LED.
And continuity mode with beeper on to see if you get an idea if it works.
If it does I think a replacement LCD would get it back in working order.

[petehall347]

Re: Fluke 289 multimeter not working

maybe a broken display ..you should be able to order new parts through an outlet .
wondering how L1 got broke .

[stj]

Re: Fluke 289 multimeter not working

your backup capacitor(c145) has leaked all over the board - send it to fluke under warranty.
this is *very* common with these shit meters.

fluke knows all about this fuckup, because they revised the board and fitted a lithium battery instead.

[Pauldg1]

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 support.

[R_J]

Re: Fluke 289 multimeter not working

I notice that the ferrite on L1 is broken, although this won't be the problem, it does seem the meter may have been dropped.

[Pauldg1]

Re: Fluke 289 multimeter not working

I notice that the ferrite on L1 is broken, although this won't be the problem, it does seem the meter may have been dropped.

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?

[Per Hansson]

Re: Fluke 289 multimeter not working

You can desolder the supercap, it is not needed for operation.
It is only to have correct date/time when using the logging feature.
You can measure how much power the meter draws before/after doing that.
P.S: There is also a TX debug console you can hook up to see where it gets stuck.

[redwire]

Re: Fluke 289 multimeter not working

Tantalum C51 looks burnt black stripe (near XBT1 pads) and inductor L1 is chipped. I would check both parts.

[Pauldg1]

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?

[Pauldg1]

Re: Fluke 289 multimeter not working

Tantalum C51 looks burnt black stripe (near XBT1 pads) and inductor L1 is chipped. I would check both parts.

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.

[stj]

Re: Fluke 289 multimeter not working

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?

the interface is optical,
if you search you will find home-built adapters.
or i can dig out some links in a day.

[Pauldg1]

Re: Fluke 289 multimeter not working

You can desolder the supercap, it is not needed for operation.
It is only to have correct date/time when using the logging feature.
You can measure how much power the meter draws before/after doing that.
P.S: There is also a TX debug console you can hook up to see where it gets stuck.

The current consumption is 68mA @9vdc with and without supercap.

[Per Hansson]

Re: Fluke 289 multimeter not working

68mA is way too high, is anything getting hot?
The debug TX goes via a dedicated circuit, not the optical interface.
It is the unpopulated connector J5 on the PCB.
I am not sure about the pinout, but you can check it with a scope.

[Pauldg1]

Re: Fluke 289 multimeter not working

68mA is way too high, is anything getting hot?
The debug TX goes via a dedicated circuit, not the optical interface.
It is the unpopulated connector J5 on the PCB.
I am not sure about the pinout, but you can check it with a scope.

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?

[stj]

Re: Fluke 289 multimeter not working

minicom

[Per Hansson]

Re: Fluke 289 multimeter not working

Yea or just PuTTY, I think it is just 8N1 115200 like most default things are...

[Pauldg1]

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

[Per Hansson]

Re: Fluke 289 multimeter not working

You can compare to some of the posts in this thread now that eevblog forum is back after the server outage, there is also included the pinout of connector J5:
https://www.eevblog.com/forum/repair...61/#msg1393861

Late edit: does Q22 go to the buzzer? If so it is weird that it is hot...

[redwire]

Re: Fluke 289 multimeter not working

It might be a speaker? Q22 has a clamp diode CR8 and 10R resistor so it's doing something higher current. If Q22 is on, it might be the MCU output that is stuck on. During RESET the MCU 's outputs all float so it should be off then. It implies the MCU is not working. I would check all power supply voltages for the '430.
1AM (SOT23) 2N3904