My Fluke 289 displays "warning leads connected incorrectly" after the case open

[Binhnt]

Hello eevblog members,

I am new to this forum.
Somebody please help as  I have a big problem with my used fluke 289 that I bought from ebay recently. 
At first it worked nicely. Then last days, i decided to check what inside with curiosity. 
After openning all, even unplugging the LCD cable to check and clean dust If there was any, I put them back together as easy as I could. Nothing special to say, but the probelm came when I turned it on after that, it only displayed the error warning message of "Leads connected incorrectly" together with the chirping sounds. 
I am stucked at this step from then, no way to use the meter any more.
Some one has experienced this, please help to advise me what to do ?
Your inputs are really really appreciated.

[plesa]

Try to clean area bellow banana sockets. I suppose that 289 has optical detection of leads.

[retiredcaps]

Check your input jacks for dirt/debris.

https://www.eevblog.com/forum/repair/fluke-189-teardown-repair/

https://www.eevblog.com/forum/reviews/fluke-287-input-alert-diode-type-replacement/

[Binhnt]

Thank plesa and retiredcaps for your suggestions, I already did try to clean the jacks and the sensors.
I may try one more time with the cleaning.
Is there any error with the board or the way i put them back together that might cause the bad result like that ? Maybe something was disconnected unexpectedly ? I am so sad that such thing can happen easily to a good product like this.

[retiredcaps]

Is there any error with the board or the way i put them back together that might cause the bad result like that ? Maybe something was disconnected unexpectedly ?

Try another cleaning.  If it doesn't solve the problem, post clear focused pictures of your pcb and maybe we can spot something.

[plesa]

I will prior another investigation reset to factory defaults and upgrade firmware. If it is not some sensitivity bug. And after that check the photodiodes an phototransistor if they are working properly.

[Binhnt]

Again, thank plesa and retiredcaps.
I will do as per your directions.
But the reset function, how to do that? It seems that when turning on, I can do nothingelse except to edit the time. I also do not have the IR cable either.
I will do the clean up again and report.

[Binhnt]

Hi, after a close up examination, and read the teardown of fluke 287 at the link. https://www.eevblog.com/forum/reviews/fluke-287-dmm-teardown-and-photos/msg52680/#msg52680
I compare and distinguish the missing diode like this picture.
Please advise me where to buy one to sold it in place.
Thank you.

[Macbeth]

Have you checked your vacuum cleaner bag for it?  (Been there... done that!) 

[Binhnt]

  

It is really a shame Macbeth, such small piece can not be found easily.
Since tha last post, I have tried everywhere for such an extremely tiny thing, and so far, there is no such thing in my sight. I got to get a new one. Please let me know the place where i can get it.
Thanks.

[Stray Electron]

OP,

  Oh what ranges is this happening?

[Binhnt]

OP,

  Oh what ranges is this happening?

It happens at boot and no probes or leads connected.

[Macbeth]

I imagine any SMD 0805 IR LED would do the job? You probably don't have any on hand but you must have some old scrap TV remote controls you could desolder the more than likely standard through hole IR LED from and use that as a stop gap? Make sure you solder it on the pads the correct way around 

[Binhnt]

I imagine any SMD 0805 IR LED would do the job? You probably don't have any on hand but you must have some old scrap TV remote controls you could desolder the more than likely standard through hole IR LED from and use that as a stop gap? Make sure you solder it on the pads the correct way around 

Wow, that is a supprisingly good idea, Macbeth, I will try it outside first to detemine the good working one.
I also look around and found this thread :
 https://www.eevblog.com/forum/reviews/fluke-287-input-alert-diode-type-replacement/
But I think to find the IR led of 980Nm emitter is not easy. 

[Binhnt]

Problem solved!
I try to look everywhere I can think of the possibility, specially the dustbin and finally found the tiny peice of DS2 IR Led.
Lesson learned, be careful when dissembling those DMM!
They may look strong but infact they are very fragile.
Just the pictures for your reference how small it is. 

[tron9000]

Whoa! Wait! 

you actually found that tiny thing!

your either incredibly lucky or have unbelievably sharp eyes!

[Binhnt]

Whoa! Wait! 
you actually found that tiny thing!
your either incredibly lucky or have unbelievably sharp eyes!

You are right, tron9000  ,
I think I am both lucky and regretful to the loosing so I keep looking for it.
Because I know where it should be and I also remember how I could have been losen that IR Led.
You know I tried to find it 2 times in the night with a porch with no result! 
I have to wait for the day light to open up, spread the dustbin again this morning. You got to look very closely to the garbage, dust and sands..etc. it is alot easier as you know what you are searching for, right ?
Those are some experience to someone who may be in such trouble like this.
It seems that I solved the problem myself but infact you guys really help.
I myself can not find the thing without your suggestions.
Now my fluke is working beatifully again and for long time I hope.
Thank you all of you and this awsome forum!

[Macbeth]

See, I told you... The little bastards always end up right at the bottom of all the rubbish. Like looking for a needle in a haystack. With a cushion for your knees, decent torch and possibly a magnifying glass you find it in the end. Another tip for finding tiny screws and metallic stuff that dissapears is a magnet on a stick!   

I really shouldn't be so clumsy.

[GreyWoolfe]

See, I told you... The little bastards always end up right at the bottom of all the rubbish. Like looking for a needle in a haystack. With a cushion for your knees, decent torch and possibly a magnifying glass you find it in the end. Another tip for finding tiny screws and metallic stuff that dissapears is a magnet on a stick!   

I really shouldn't be so clumsy.

The magnet on a stick is the greatest thing since sliced bread.  I keep one in my tool bag for work as I regularly drop screws inside equipment and I keep one in my tool chest at my workbench.  Both are collapsible, so I get some reach out of them-I 'sweep' the floor under my workbench when I drop small screws-almost 100% recovery.

[Binhnt]

Wow, I didnt think of the magnet to do that " finding a needle in the haystack".
There it is, alot to learn from this incident. Happy ending happens finally.
I occasionally see this kind of error in some auctions at ebay.
Keep looking for it to find a good deal sometime 
I am still looking for another Fluke 189 for portability and cleaning   

[Ronsonic]

Hi, I just want to thank everybody involved in this thread. In fact, I registered here just so I could do that.

My used 289 intermittently but frequently gave a false lead connection warning. After reading this thread I opened it up very carefully (now that I knew what to expect) and found D2 laying on the clear plastic bezel right where it had fallen off the board. Soldered that puppy back in place and it's working perfectly.   

I'm guessing there's a lot of stress there when it gets dropped and leads get manhandled and the solders get overstressed.

So, thanks again all. Nice forum here, I'm gonna look around. 

[M0UKD]

Thanks to Binhnt. My 287 started having this issue, I thought it was just dirt but realised that if I pushed the probes it would come and go.

Just like Ronsonic, my IR LED D2 was also laying on the clear plastic bezel when I opened it up. I think this LED actually touches the clear plastic, and it's that stress from flex in the meter case that must work it loose. Bit of a design flaw, just like the super capacitor (that I already removed before it leaked everywhere!)

Thanks for pointing me in the right direction guys!