Fluke 287/289 IR Lead Detection Fault
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- Опубліковано 8 жов 2024
- Some of the Fluke meters that I have seen use an infrared beam to detect whether the test leads have been inserted into the ammeter inputs. Other users have reported problems with this circuit where the IR LED has come off the PCB. See here:
www.eevblog.co...
www.eevblog.co...
In my case the LED was not emitting any IR although it had the correct forward voltage drop for a 10mA current.
I used an old digital camera to look for IR coming out of the diode when I powered it from a 10mA current limited bench PSU. Note that many newer cameras, including phones have an IR filter and you cannot detect IR.
I identified that IR LED as:
Kingbright KP-2012F3C INFRARED EMITTER, 940 NM, 0805
I bought a pack of 5 from Farnell (2290432) for less than £1.
Be aware that the LED needs to be soldered flat to the PCB so that it fits correctly into the light guide in the front of the case. Also note that the probe lead detection only works with the PCB fitted fully into the case front. - Наука та технологія
Thanks alot for this tip!
I repaired my 289 which had the same issue. My LED was still in place and lighting up, but apperently to weak.
Now its working great, again :)
A couple of people have reported the same problem. I don't know why the LED should have a reduced output after time. This area certainly seems like a weak point in the design. It's a shame as the rest of the meter seems to perform reliably.
Do you happen to have the part number for the LED?
@@PatriotDad Yes:
I used KP-2012F3C IR LEDs, ordered from Farnell: 2290432
Good luck, repairing your meter!
Regards
Just repaired mine, Thanks!!
My SMD IR was just weak or dead, bought a strip of 5 pieces (Kingbright KP-2012F3C, 940 NM, 0805) for ~1.50 euro, transport cost were crazy more then 10 euro 🤣
First time SMD soldering went very well thanks to some educational vids on YT😉. (good and bad vids out there on how to do it, use your brain to filter out the good and do it nice).
I needed to buy the right super small tip (XT HX) for my Weller iron, very thin tin (0.2mm)😉, I also bought a new bottle of flux (TK83 no clean).
Make sure you get the old tin clean off, because you need to seat it flat on the print, can recommend looking for some no clean desoldering wire (I used Techspray no clean).
Using my phone as a magnifying glass was a bit clumsy but it worked, need to fix that problem in the future or buy a new pair of eyes like in cyberpunk 2077😇.
My end total cost were below 50 euro and got my Fluke 287 back + new soldering tools + new skill level unlocked😜
Thanks again! and good luck if you have the same problem!
Fixing your nice battery eating fluke is worth it😛.
Also VERY important⚠❗
If you screw your fluke back together remember to turn the screws counterclockwise slowly till you feel it fall in the thread, after that you can turn them clockwise😉, because those screws will try to tap a new thread if you don't and you won't like the result if you do that to often!😉
Good effort, welcome to the exclusive band of 'Fluke Repairers'.
Repaired a 287 and a 289 after seeing the video. Thank You for naming the part !
Thanks for this video. I just fixed my 287. I was installing led bottom up !!!!!
Thank you very much
For good info and for the link
Fixed and working perfectly
It is surprising how many of these meters fail in this way.
Just a quick added tip. My LED was in place, but it was still showing up on camera, so I was baffled. I replaced it anyway, and the new one was a lot brighter. So do try replacing it even if you can see the light from the old LED.
Gracias amigo por compartir reparación tengo un fluke 287 preg ke fallas presentas gracias por tu orientación feliz navidad
Спасибо, помогло Ваше видео. Пропаял излучатель, промыл спиртом и всё заработало!
Я рад, что это помогло вам. К счастью, моя электроника лучше моего русского.
Он инфракрасный?
Thanks!! I just solved mine in 10 sec 😂
Diagnosing mine I did the same thing as in the video but instead of using a camera without an ir filter I used an infrared detector card (Heartwood Fidc)
Amigo buenas tengo un problema con mi Fluke ya que una de las pistas de inflarrojo se dañó de pronto conoces algún método para puentiar esa señal y lo deje trabajar normalmente
Intentaría reparar la pista rota; de lo contrario, tendrás que usar el circuito de activación del LED para controlar un par de transistores cuyo colector y emisores están en paralelo con los fototransistores. La forma de hacerlo depende de qué pista esté rota.
¡Buena suerte!
My 287 was doing this.
Now, it will not even come on.
I tried new batteries since it had not been used in several months that I have had it and 3 batteries showed to be weak.
I am used to way cheaper meters but need to know more about these and how to use them.
My experience with these meters is that they are generally reliable. We have a lot of them at work and they don't usually give any trouble. In the past when I have a meter that is not powering up then I suspect the battery connections in the battery box. If any batteries have leaked then this often damages the contacts, so I would start there. Beyond that you will need some other test equipment and some knowledge of electronics to fix it. I don't think that there is a schematic available for this meter online so you would have to determine how the circuit works. If it were me I would start by looking at where the batteries contact the main PCB and trace it through from there. You could always connect a bench PSU like I did in the video and see how far the voltage gets in the circuit. Be careful as you can cause a lot of expensive damage to the board if you over-voltage it.
Hello! Tell me please I have the same problem but the diode is in place !What can be checked and replaced ???
My diode was also in place but faulty. Just replace it, they are not very expensive.
@@bvqbvq Can you tell me what the symptoms were and what the breakdown was ?Have you tested the diode with a tester ?
@@mikhailshulgin6965 I explained it all in the video. To test the LED you need a current limited power supply (10mA) and an old digital camera capable of viewing IR. You can do this with the LED in circuit. If there is no visible IR and you have a sensible forward bias voltage (1.6V) then the LED is faulty and you need to replace it. If it is emitting then you can use it to test the phototransistor although you may need to guide the light or reflect it with something. If that is working then you need to start looking at the LED drive circuit.
Display shows leads connected wrongly fault without connect leads why
Take the 289 apart, there are 6 phillip head screws that hold the unit together. After some breakdown, you'll come across 4 smaller screws that hold the PCB down to the back side of the banana clips. You'll also notice that two more screws are located on the board. After a breakdown of the unit, carefully remove the LCD ribbon cable from the PCB and do a visual check of the bottom of the PCB. In your situation, it might just need a good cleaning. I cleaned my 289 with denatured alcohol.
hi. very usefull information. I have got same problem. and I did not know why it says ''wrong lead connection'' ! is it any way to disable whole system? so I want to get rid of this security system basically. thanks for your help
Why would you want to disable it? It is there to warn you that you have the leads in the wrong position which may result in damage to your circuit or the fuse in the meter. It is very cheap and easy to fix. If you can afford to buy one of these meters, the cost of fixing it yourself is surely in the noise...
I have same problem ,thankyou
hi. I found my fluke 287 has same problem and when I tested the emitter LED was fine and only left receiver transistor was not working .do you know the part number for receiver transistor please ?
All the details are in the description below the video, click on Show More...
Do you happen to have a part number for those IR photo detectors ?
Yes, it's in the description above: Kingbright KP-2012F3C INFRARED EMITTER, 940 NM, 0805, I bought a pack of 5 from Farnell (2290432) for less than £1
could you pls provide us link to purchase?
uk.farnell.com/kingbright/kp-2012f3c/infrared-emitter-940-nm-0805/dp/2290432?ost=2290432
What is the led part brand and number ?
It's all in the description below the video.