Fluke 902 repair - chaotic resistance / continuity - Page 1
Forum section: electronics / repair

author: Neutral
author_rank: Newbie
timestamp: January 21, 2025, 10:25:15 pm
content: Hello,I need help how to fix the 2 following problems on a Fluke 902 clamp meter.I join pictures.1- Now the continuity position shows numbers instead of OL (with nothing connected to the probes).When i opened it, i found a small piece as shown in the picture, and discovered it fell from under the white plastic (rotary button mecanism).I searched on the internet and found a video showing reparation of a fluke376, apparently very close model to the Fluke 902 (see picture). I concluded one of the two copper small contacts broke and i need to replace it by a new one. BUT i cannot open the white plastic easily without risk to break it (Not exactly the same as in the video).2- In the beginning the backlight did not work well, sometimes ON and sometimes OFF with no intervention (or only a slight move). The display seem to work very well. Connections on the board seem in order. I have no clue why it does this.Please help me if you can.Thank you.

author: benj38
author_rank: Frequent Contributor
timestamp: January 26, 2025, 10:29:08 pm
content: Why do you think "opening" the "white plastic" as you call it would help?What you need is to improvise some repair for the broken contact, and it looks like you have all the access you need to do that.That said, your pictures of this part are not clear enough to figure out what exactly is going on, so I may be wrong.If you can remove the contact fingers from the plastic, and have the tools to do silver brazing, you can probably fix the contact if you are careful. However, the heat may cause the contacts to lose springiness, I have had mixed results doing such repairs in the past

author: Neutral
author_rank: Newbie
timestamp: February 04, 2025, 08:44:04 am
content: I could open easily, (after few careful tries), the "white plastic". I made some research, and the broken part is called "spring contact".I join some pictures to clarify.My limited skills in silver brazing could be sufficient, (may be), but a new or used part would be better, in my opinion. I am also thinking to 3D print it and make some electricity conductor coating ..Thanks for your help.

author: benj38
author_rank: Frequent Contributor
timestamp: February 04, 2025, 01:47:32 pm
content: You should be able to silver braze it easily!As for the option of getting a replacement contact, forget it. The chances you will find such a contact for sale are basically zero.A used contact on its own is not really an option either: how will you even go about to achieve that?Getting a whole new replacement switch may be more doable, but most probably only through the manufacturer (if they still offer parts for this meter), and you may not like the price. A used replacement switch is definitely an option, but most probably the only way to get it is finding a donor broken meter, which will not be easy, and possibly not economically attractive.Finally, 3D-printing something and using conductive paint does not sound like a good idea: the life expectancy of such a solution in my mind is very small to none.

author: Neutral
author_rank: Newbie
timestamp: February 04, 2025, 02:05:25 pm
content: I will give it a try. I need to buy a brazing kit, I have been thinking of for a long time. It's time now. Do you have some advice about that ?Thank you!

author: benj38
author_rank: Frequent Contributor
timestamp: February 04, 2025, 02:25:35 pm
content: The Blazer torches are great in my opinionhttp://blazerproducts.com/industrial.html. The BIG SHOT INDUSTRIAL TORCH is more powerful and versatile, but the GB 2001 MICRO TORCH is loved by many, and would do a perfect job in this and similar applications. Obviously, for such a small part, almost any torch will do.I usually use Borax for flux, and for this application I will go with a silver brazing wire of 40% or 50% silver. There are many alloys available, but I have mine for many years now and I do not remember how I got them, nor the brands.In general, the higher the silver content, the higher the price, melting temperature, and hardness (as well as somewhat increased difficulty in brazing --- but this is a very rough statement).I find the ability to silver braze to be a good thing to have. I do not use it often, but it was just the ticket on a number of occasions.

author: Neutral
author_rank: Newbie
timestamp: February 04, 2025, 02:56:46 pm
content: I was thinking of a soldering iron for electronic and electric repairs.As a "flamethrower" I have a Rothenberger superfire2 (for brazing copper etc), but it seems way too powerful, I don't really know.

author: benj38
author_rank: Frequent Contributor
timestamp: February 04, 2025, 05:15:18 pm
content: Way too big. If you are good at silver brazing, you can do it with it, but if you are a novice, I would use a gentler torch.