Saving yet another Fluke 189 - Page 1
Forum section: electronics / testgear

author: joeqsmith
author_rank: Super Contributor
timestamp: September 07, 2023, 02:04:09 pm
content: Picked up a cheap, dead, Fluke 189. The plastic is in poor condition. Looks like it was dipped in chemicals and abandoned. I suspect this weakened the plastic and it there are a lot of cracks and chips. I have a 189 I had bought dead for the purpose of transient testing. A few of the plastics parts on that meter were in better condition, so I swapped them out. All of the standoffs on the front cover were broke off and split. I used an inverted cone cutter with the dremel tool to cut these down to a flat surface and inserted brass standoffs into them, which I then covered with heat shrink. The ones towards the leads, I glued to the sidewall of the case. I replaced the supercap and bad battery clips. There was a small crack in the lens was all, so just some light polishing.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 07, 2023, 08:02:17 pm
content: Didn't get so lucky. The terminal block was damaged as well. All 4 pins for the common and voltage inputs were broke off. For now, I stole the terminal block from my beat up meter until I can get a replacement. The new meter is the one reading a count low. Doing a basic checkout, it doesn't appear anyone tried to muck with the alignment.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 08, 2023, 03:04:49 am
content: After posting about the instability problem I ran into with the 121GW, someone commented how the BM869s gives the wrong result for I assume ACmA (never heard of resistance voltage units).Showing the repaired 189 with the 789 and both BM869s meters. None of these are in cal but suggests the new Fluke is alright. Also that our viewer is clueless. I would imagine if we used a signal with high frequency, they would read different. Maybe they don't understand that. I'm showing a 60Hz sinewave.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 09, 2023, 06:29:26 pm
content: Appears there are none of the OEM terminal blocks available. There are two different red ones. Has anyone purchased one of these? Do they use rubber like the OEM parts? Sealed? Crap metal terminals from China?https://www.ebay.com/itm/234863848071https://www.ebay.com/itm/265685003138

author: daisizhou
author_rank: Super Contributor
timestamp: September 09, 2023, 10:08:21 pm
content: Have you carefully checked and cleaned the 4 terminal blocks?You must carefully clean the bottom of each terminal,It is recommended to soak with 95% ethanol after cleaning and rinse each terminal with a syringe.After all steps are completed, they must be dried and then checked to see if the data is consistent.If there are still errors, follow the steps above and try again.I think it makes no practical sense for you to replace 4 terminal blocks.First of all, it is difficult to buy brand new terminal blocks, and secondly, counterfeit terminals are not as reliable as repairing old ones.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 09, 2023, 11:51:15 pm
content: It wasn't too hard to spot all the broken pins. All of the fractures were flush with the board. These are I assume welded or molded together and I don't see a good way to repair them and maintain the seal. You would need to locate the entire post assembly. The metal pins are molded into the post. Press out the old ones and press in the new ones. Then maybe glue it together. Would rather just replace the entire assembly then try and cobble something together.I went ahead and pressed out a good and bad pin to show you how they go together.

author: bdunham7
author_rank: Super Contributor
timestamp: September 10, 2023, 12:12:23 am
content: Quote from: joeqsmith on September 09, 2023, 06:29:26 pmfluke-usa is a 100% legit seller. When Fluke ceases support, they clean out their inventory and somebody gets it. I have tracked various Fluke bits and bobs through surplus channels and I haven't found any counterfeiting yet. I have bought other stuff from fluke-usa but the 189 terminal block I bought through Newark, of all places. As always, YMMV--you pay your money and you take your chances.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 10, 2023, 12:22:22 am
content: Fluke USA it is. Thanks.

author: daisizhou
author_rank: Super Contributor
timestamp: September 10, 2023, 01:09:22 am
content: It has many imitations in China.If you replace it without the original soldering material, there may be errors--I mean measurement deviation

author: joeqsmith
author_rank: Super Contributor
timestamp: September 10, 2023, 04:24:29 pm
content: Quote from: daisizhou on September 10, 2023, 01:09:22 amPlease provide references and details.

author: daisizhou
author_rank: Super Contributor
timestamp: September 10, 2023, 09:12:33 pm
content: picture

author: bdunham7
author_rank: Super Contributor
timestamp: September 10, 2023, 10:16:18 pm
content: It entirely possible that the current OEM part is made in China. The old ones were apparently black while the new ones are red. The part is still used, AFAIK, in the 787B and 789 products. I can't find the one I got from Newark a while back, once I'm mobile again I'll dig it out. I'm pretty sure it was red. I see the two eBay sellers have pictures with slightly different appearance--thefluke-usaversion doesn't have the machining marks the other one does. I'm assuming the Newark-sourced version, which is NLA through them, would not be counterfeit.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 10, 2023, 11:52:06 pm
content: Quote from: daisizhou on September 10, 2023, 09:12:33 pmThese do not appear to be the correct replacement for the 189. See the ebay links I provided.Quote from: joeqsmith on September 10, 2023, 04:24:29 pmI was more curious about your comment about the original soldering materials. I doubt anyone is mixing solders or not soldering them in. My interpretation of what you wrote is that if the original solder is not used, it may cause errors. This is what I am asking for details on.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 11, 2023, 12:02:50 am
content: I mentioned I had stole the best parts from my worse meter to repair the new one. One of the things I stole was the rubber keypad. I noticed when I reinstalled the terminal block and functional tested it, only two of the buttons worked. It looks like what ever chemicals this was exposed to damaged the rubber contacts.I had used some of MGChemicals conductive paint for some 3D printed microwave horns I was testing. I sprayed a small amount into the cap and used a toothpick to apply a small bead on the end of the rubber. Let it dry overnight. All of the buttons works fine again.https://www.eevblog.com/forum/rf-microwave/experimenting-with-waveguides-using-the-litevna/msg4638982/#msg4638982

author: daisizhou
author_rank: Super Contributor
timestamp: September 11, 2023, 01:04:35 am
content: The error I am referring to is that there may be deviations in the measured values.As far as I know, the soldering material used in the original factory FLUKE 187/189 contains silver，And ordinary soldering tin rarely contains this silver material.Another issue is that if the solder contains silver, its welding temperature will increase. If you replace the seat, you will find that the solder pad will become focal, which can also lead to measurement deviation.So I generally do not recommend that everyone replace this seat themselves unless it is truly beyond repair

author: daisizhou
author_rank: Super Contributor
timestamp: September 11, 2023, 01:12:13 am
content: Black rubber material for the end of your button----One approach is relatively simple, using a conductive metal film with adhesive force on one side and conductive on the other side，You only need to cut a small disc and paste it accurately in the original black position.Another method is to use conductive rubber adhesive, but this method is complex, but it can last for a long time after repair

author: joeqsmith
author_rank: Super Contributor
timestamp: September 11, 2023, 01:26:36 am
content: I pulled both terminal blocks at 640F. No trouble at all and both appear original. Do you have a document from Fluke that talks about the need for a special silver solder? Something you were told? I'm interested in hearing more about this.I am not sure what the seat is or what is meant by pad becoming focal. Plan will be to replace the entire terminal block. Again, the terminal block is molded into one part. The pads stay the same.I use copper foil tape which sounds like what you are suggesting. I'll let you know how the conductive paint holds up.Video showing same repair I plan to do.

author: daisizhou
author_rank: Super Contributor
timestamp: September 11, 2023, 02:43:05 am
content: I drew a schematic diagram,When you weld, you increase the welding temperature of the soldering iron,So it will cause discoloration of the PCB insulation layer,If the temperature is too high, it will cause two welding points to conduct and have resistance.I'm referring to turning brown,To be precise, the PCB insulation layer is affected by temperature,Causing the previously insulated part to become conductive now

author: joeqsmith
author_rank: Super Contributor
timestamp: September 11, 2023, 03:42:51 am
content: Attached are photos of the new meter. Consider I had pulled the original terminal block, then installed the one from my bad meter, then removed it again. So 4 heat cycles so far when you include the factory original install.I wonder if someone used lead free on the boards you worked on. Normally I solder around 620-640F. Not enough to damage the board.Pins for the com and V are shorted on the board. The current inputs are open for the sense. Because you are not measuring through the two pins, it shouldn't effect the measurement. With the damage you describe, it could however cause the LEAdS error.

author: daisizhou
author_rank: Super Contributor
timestamp: September 11, 2023, 03:57:16 am
content: You have good temperature control, but few people are able to do so

author: Shock
author_rank: Super Contributor
timestamp: September 12, 2023, 02:54:41 am
content: Most input problems are more likely residual contamination (leakage) problems first, not soldering by a beginner. Which is why you need to clean the area like your life depends on it before the oem part is replaced.I'd solder it with close to the original alloy though if it matters. Do a sanity test and pay close attention to settle times, repeatability and current draw. If still a problem then I'd ditch the super cap and thoroughly clean and dry the pcb before anything else. Knowing it's not been poorly calibrated is really helpful as it sets a baseline to repair to.Dave just did a video on board leakage btw.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 13, 2023, 01:01:24 am
content: Quote from: Shock on September 12, 2023, 02:54:41 amWhile I did show photos of the broken pins, I'm guessing you did not see them. No cleaning is going to help this meter.So the new terminal block arrived from FlukeUSA. I'm not impressed. It looks like a Chinese knockoff rather than the quality I see with the OEM parts.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 13, 2023, 01:07:20 am
content: Shown with a 1k, 1Gohm and 100uADC applied. Ran through all the basic tests an it appears in good order now.Would be nice if there was a way to repair the rubber on these but I guess the scars on all of mine give them character.

author: daisizhou
author_rank: Super Contributor
timestamp: September 13, 2023, 01:33:26 am
content: This seat doesn’t look very “exquisite”.Maybe it works, but it's not perfect

author: joeqsmith
author_rank: Super Contributor
timestamp: September 13, 2023, 01:46:19 am
content: Whole meter is far from perfectI would rather have the OEM block but I guess this expensive knockoff is about as good as it gets.

author: bdunham7
author_rank: Super Contributor
timestamp: September 13, 2023, 02:02:25 am
content: Quote from: joeqsmith on September 13, 2023, 01:01:24 amIt would be surprising and disappointing if the sellerfluke-usawas shipping knock-offs. I'll try and find my replacement from Newark and compare. I know the bodies are all-red now, but what else seems bad about it?

author: joeqsmith
author_rank: Super Contributor
timestamp: September 13, 2023, 02:17:13 am
content: Did you notice the machine marks in the mold? Similar to what the other eBay store had. The other thing I noticed is the OEM boots are a very soft plastic or hard rubber. You can squish it easily between your finger tips. This red one is a very hard plastic. Will it crack or split in short time like I see with cheap Chinese meters? I can't comment on the contact itself.***Squeezed the OEM a small amount, then more. As soon as I release my grip, the part returns to normal. The rest of the OEM terminal block is hard plastic.

author: bdunham7
author_rank: Super Contributor
timestamp: September 13, 2023, 02:24:18 am
content: Quote from: joeqsmith on September 13, 2023, 02:17:13 amYes, I saw that. If the OEM part is NLA from Fluke, we'd accept a Chinesium knock-off. But the fluke-usa description specifically warns us about knock-offs! I don't know. One possibility is that Fluke is having them made in China now, or has switched vendors to some US-based barbarian. I've seen much worse things come from US automotive suppliers, so bad that in many cases the Chinese knock-offs were an improvement.Did you call Fluke about that part, using the updated part number? If it is NLA from them, you have to wonder what is going on.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 13, 2023, 02:31:00 am
content: I never called Fluke as the meters are so old I wasn't expecting any service. See my attached photos in my previous post to get some idea how the OEM part will flex. Its easy enough to try and squeeze the new part with needle nose pliers at the tip. These are totally different materials. My guess is the original designers had a reason for this.

author: bdunham7
author_rank: Super Contributor
timestamp: September 13, 2023, 02:45:52 am
content: Quote from: joeqsmith on September 13, 2023, 02:17:13 amMy 189 has squishy boots as well, but my much newer 289 does not, they are hard. My older i1010 current clamp has flexible shields, my newer (and cheaper) i400e is totally rigid. Maybe that flexibility depended on some additive that was expensive or bad for the environment. Short of buying a new 789 just to fondle its boots, I'm not sure what to say.

author: daisizhou
author_rank: Super Contributor
timestamp: September 13, 2023, 02:49:16 am
content: This is what I mean by "imperfect"。Maybe Fluke has outsourced the production to a counterfeit company.Because this instrument has stopped providing after-sales support.And for your plastic material itself,Looks like it has no flexibility，If you use it for a long time or use it violently,I reckon it will break soon.So I always recommend repairing it and not replacing it as much as possible.

author: bdunham7
author_rank: Super Contributor
timestamp: September 13, 2023, 02:59:43 am
content: Quote from: daisizhou on September 13, 2023, 02:49:16 amFluke wouldn't do any such thing for a product that is out of support, they simply list the part as NLA and tell you they don't have it. The only reason they would continue selling this particular part is that it is still used in some current products. It may simply be updated and redesigned. Perhaps flexible is not better, IDK.

author: Shock
author_rank: Super Contributor
timestamp: September 13, 2023, 05:36:37 am
content: Quote from: joeqsmith on September 13, 2023, 01:01:24 amI did read the thread, in part it was a response to what daisizhou said. I was pointing out soldering pins would more likely exacerbate a contamination problem should it exist, rather than directly cause it.The integrated holsters and low set sockets near the bottom edge on the Fluke 189 aren't my favorite features. Here are some high res photos of the legitimate ones. I'm leaning towards your replacements being chinese knockoffs.Could be a problem with too flexible sockets when non shrouded banana plugs are used. Less rigidity to prevent the internal contacts moving and transfer stress to solder joint or pin at the pcb.

author: daisizhou
author_rank: Super Contributor
timestamp: September 13, 2023, 06:57:38 am
content: Quote from: Shock on September 13, 2023, 05:36:37 amCleaning requires great care,I always stress the need for a practical syringe to flush the bottom,and needs to be soaked in ethanol.Many people don’t understand what I say, so they will fail.I have a 187 myself, and this is how I repair it.When I have time I will shoot a video, maybe it will make everyone understand better

author: joeqsmith
author_rank: Super Contributor
timestamp: September 13, 2023, 02:03:59 pm
content: Quote from: bdunham7 on September 13, 2023, 02:59:43 amQuote from: Shock on September 13, 2023, 05:36:37 amPossible. This is now the fifth 18x in my collection. It's the only one with fractured pins. Three of the meters, including this one, were used in harsh conditions. Two of them, including this one have a lot of damage to the plastic and rubber. I would say all five have lived far beyond what I would expect. So from my small sample size, the soft insulators were not much of a problem. I wonder if they helped form a seal around the connector or base.

author: Shock
author_rank: Super Contributor
timestamp: September 14, 2023, 02:43:57 am
content: I have 3 but one of them needs work. As long as they can run in spec and have repeatability I'm not too worried about age. Have your Brymen BM869s drifted yet at all? Any outstanding bugs/flaws?If you have a set of four, your next task is to make them all agree.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 14, 2023, 12:00:10 pm
content: Quote from: Shock on September 14, 2023, 02:43:57 amI recently posted comparing my 7YO BM869s with my HP34401A using 500mVDC and measured50uV30uV (typo)difference. My Fluke 18x measure -50uV to 70uV (new meter lower left). But again, none of my equipment is in cal and I don't track their drift. J-R was also suggesting aligning my BM869s using some of those cheap calibrators. You can read about that here:https://www.eevblog.com/forum/testgear/brymen-bm789-360289/msg5031622/#msg5031622As far as bugs with the BM869s, nothing off the top of my head. I did change the firmware (IC replacement) on one of them to increase the backlight timer. Hardly a bug. You would need to search my posts. If I ran into a problem or attempted to replicate someone else's test, I would have posted about it.

author: Veteran68
author_rank: Frequent Contributor
timestamp: September 14, 2023, 01:14:33 pm
content: I've always wanted a 189 to add to my collection of DMMs. Not that I need it for any practical purposes, I have some excellent meters, many of which are safely tucked away unused. But collecting DMMs has become an obsession/addiction/illness, and the 189 just checks a lot of boxes for me. I hate they discontinued it. Conversely, I have no interest in the 28x series at all, and really fail to see their attraction, the price:performance ratio just doesn't interest me.I'm watching a 189 on eBay now that ends in a few hours -- someone please bid it way up and buy it so I have a good excuse for passing it up. I've bought too damn many DMMs in the past few months.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 14, 2023, 02:23:12 pm
content: Quote from: Veteran68 on September 14, 2023, 01:14:33 pmTargeted more the electronics side than electrical. Maybe it wasn't a big profit maker. Then again, the one my old friend had given me was owned by a company and assigned to a friend of his who had passed away. This company had written custom software for their field techs that supported this meter. When that company was bought out, the new company continued to support that software. Eventually they could no longer get these meters from Fluke and they changed brands. So maybe it wasn't that there was a lack of demand but maybe a part obsolescence.The 189 is just a nice basic meter. Easy to program from the PC. If I had to buy a new meter today, it would still be the BM869s.

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2023, 03:24:37 pm
content: Quote from: Veteran68 on September 14, 2023, 01:14:33 pmGet a 187, it's the same meter (apart from internal datalogging) but no pesky supercap to fail and ruin it.

author: Veteran68
author_rank: Frequent Contributor
timestamp: September 14, 2023, 04:05:36 pm
content: Quote from: Veteran68 on September 14, 2023, 01:14:33 pmMissed it by that -->||<-- much! Was outbid with 4 seconds to go. Good, LOL.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 14, 2023, 06:05:54 pm
content: Quote from: Fungus on September 14, 2023, 03:24:37 pmOr, maybe just replace the old parts before they fail? Mine are all new (see 1st post).

author: daisizhou
author_rank: Super Contributor
timestamp: September 14, 2023, 10:12:26 pm
content: I think the most attractive thing about 187 is the AD chip specially designed by FLUKE,Many modern instruments 17x, 87, etc. use M430 microcontroller to replace the AD chip.I always feel that hardware AD chips are more refined than general-purpose MCUs.