Testing the Fluke meters

Article By : Paul Rako

Making a bad design efficiently is not an optimal business practice. Thing is, engineers value on trusted brands so maybe spend some money on engineering, and even more on testing.

« Previously: How to deal with battery corrosion in Fluke meters
So once I had the Klein Tools MM600 DVM working, I could see that the terminals in both Fluke meters were getting the full battery DC voltage. My fury dissolved into sorrow as I worried that I had a $1,000 of dead voltmeters. I opened the Fluke meters up and they both use a set of prongs pressing against gold-plated pads to apply the battery voltage to the motherboard (Figure 10). Gently bending the prongs up to apply pressure to the pads on the circuit board fixed both meters.

20170808_EDNA_Fluke-dead-10 (cr)

Fearing that the meters would only corrode again, I got out my spray cans of DeoxIT D5 and DeoxIT G5 (Figure 11). The G5 is meant for gold-plated terminals and was in stock at the local Radio Shack. The D5 I bought on Amazon. DeoxIT works great to clean, renew, protect and lubricate any contact surface. I learned about it from my Ham radio buddies, who have used it for decades to keep their gear working. It is also great on those rotary switches in test equipment. Lubricating connectors does not impair their conductivity, but will eliminate scuffing and spalling under vibration.

20170808_EDNA_Fluke-dead-11 (cr)

I didn’t spray the DeoxIT G5 into the meter. I just sprayed it into space, and then touched the spray tube to the gold pads in the Fluke meters (Figure 12). I saw no need to get all the delicate circuits wet, especially since the Fluke meters can measure high impedances. If a fingerprint can affect a PCB resistance, so might a bunch of DeoxIT sprayed willy-nilly into the case. I used the DeoxIT D5 on the nickel-plated battery terminals.

20170808_EDNA_Fluke-dead-12 (cr)

Both meters worked fine once I fixed the prongs in the case (Figure 13). I am hoping the DeoxIT will keep them working. It’s been six months, and so far, so good. A happy ending, but there sure was a lot of fury getting here.

20170808_EDNA_Fluke-dead-13 (cr)

Since the days I bought these meters, Fluke was acquired by Danaher Corporation. Danaher also bought Tektronix, last year; it spun off these and other test businesses into a new and separate company, Fortive.

Danaher found success in learning how to manufacture things, adapting Toyota’s fabulous production system to non-automotive manufacturing. I just hope that the fine folks at Danaher, and now Fortive, understand that the Toyota Production System (TPS) was only a part of the Toyota Way, an all-encompassing management philosophy. TPS is all about lean manufacturing. It uses principles of just-in-time manufacturing and continuous improvement. It’s all about efficiency, and efficiency is something finance people love, since they care more about money than things or people. The Toyota Way is much more complex and subtle. I once read that one aspect of it is actually duplicating effort. So if part of the engineering team thinks it's best to design a product one way, but the rest of the team want to do it another way, it’s best to develop both designs, until testing, manufacturing and assembly considerations are evaluated by management. Toyota does not let bully managers or bossy engineers take over the program. They have respect for the quiet engineers.

I assume there will be some quiet engineer at Fluke that wants to redesign this abominable battery terminal connection to the PCB. Perhaps they have done so already. Every time I see system engineers thinking they can design connectors, I see problems like this. Leave connector design to Amp, Molex and Amphenol. I would eliminate the connector altogether and solder a battery holder into the motherboard. That would require a complete case redesign, so I can see the cost might be prohibitive. Perhaps just use wires to connect the batteries to the motherboard. Anything is better than this spring-loaded monstrosity. Perhaps the case halves need strengthening to keep pressure on the gold pads. In any event, Fluke should use heavy gold plating over the nickel-plated battery terminals.

It’s nice that Fluke goes to so much trouble to make the case water resistant. I guess that is a necessity for industrial meters, but I just use mine at the lab bench or in my garage. I would rather have the batteries exposed so they leak out of the case, rather than a hermetic design that ensures the whole guts get corroded when the batteries inevitably leak. Inevitably.

Making a bad design efficiently is not an optimal business practice. I assume Danaher spun off Fortive when it realised competition from China means they can’t get those 53% gross margins they need to keep the executives in limousines. Thing is, engineers place enormous value on the trusted brands like Fluke or Tektronix, so maybe spend some money on engineering, and even more on testing, then price the products according to their design excellence. We will pay. That way the finance folks can be happy, not to mention the engineering team and the customers.

First published by EDN.

« Previously: How to deal with battery corrosion in Fluke meters

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