Post by thread:[EE]: Fluke meter LCD problem

Got a Fluke 8060A DMM here, that has had an LCD problem since it was new. The LCD display is dim, and over time has dimmed more to the point where it's almost gone. I used to be able to see enough to use it, and it worked well otherwise. Any thoughts on what might be wrong, or how to go about analyzing this? I'm hoping that it's just a display connector or something simple. Cheers, -Neil. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 01:57 PM 8/10/02 -0500, you wrote: >Got a Fluke 8060A DMM here, that has had an LCD problem since it was >new. The LCD display is dim, and over time has dimmed more to the point >where it's almost gone. I used to be able to see enough to use it, and it >worked well otherwise. > >Any thoughts on what might be wrong, or how to go about analyzing this? >I'm hoping that it's just a display connector or something simple. Try carefully cleaning the zebra connectors and surrounding PCB with alcohol. Look first for signs of electrolyte leakage from the e-caps, replace if you see any. Try the ratio self test, courtesy of Malcolm Moore: - hold the continuity/beeper button while turning meter on - keep it pressed until POST is complete (8.8.8.8. on display) and release - the meter should now read 10000 +/- 5 counts (decimal point is based on range switch and doesn't matter). Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" spam_OUTspeffTakeThisOuTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com 9/11 United we Stand -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

>Got a Fluke 8060A DMM here, that has had an LCD problem since it was >new. The LCD display is dim, and over time has dimmed more to the point >where it's almost gone. I used to be able to see enough to use it, and it >worked well otherwise. > >Any thoughts on what might be wrong, or how to go about analyzing this? >I'm hoping that it's just a display connector or something simple. If it has a rechargeable battery, make sure the battery voltage comes back to normal when you recharge it. I believe bad batteries can cause display dimming and other problems too. Reg -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Neil, I have a Fluke 87 DMM built somewhere around 1993 to 1995, and it periodically needs repair for the same symptoms you described -- a gradual "dimming" of the LCD display. Maybe a better way to describe it is a loss of contrast so that the numbers no longer appear different from the background. A couple Fluke reps at a trade show immediately knew the problem (guess it was common) and showed me what to do. The meter must be disassembled to the point where the LCD glass can be removed. There are a couple rubbery components that are apparently the (non-metallic) conductors to the LCD glass. I'm not familiar with the construction technology, but they need to be cleaned, perhaps with a swab moistened with alcohol. They may have used a pencil eraser, I don't recall at this point. I just did mine a few minutes ago to prepare this response. This is probably the third time this repair has been needed. The display had become so faint that I haven't used it meter for some time. I hope yours is the same thing, and is as easy to perform as on the 87 (which is now working fine once again). Best wishes, Randy Jones {Original Message removed}

> The meter must be disassembled to the point where the LCD > glass can be removed. There are a couple rubbery components > that are apparently the (non-metallic) conductors to the LCD > glass. Zebra strips Strange that this should happen to a quality product like Flukes. I've used reasonable but cheap meters for years and never needed to clean those conductors. Same with my VCR remote, which has a programming LCD on it, and gets absolutely gross inside with, well, ever cleaned out a remote control ? Ick ick ick -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

What would a touch of "Caig" contact enhancer do I wonder? RF Jim ----- Original Message ----- From: "Randy Jones" <.....randyjonesKILLspam@spam@WORLDNET.ATT.NET> To: <PICLISTKILLspamMITVMA.MIT.EDU> Sent: Saturday, August 10, 2002 8:07 PM Subject: Re: [EE]: Fluke meter LCD problem > Neil, > > I have a Fluke 87 DMM built somewhere around 1993 to 1995, and it > periodically needs repair for the same symptoms you described -- a gradual > "dimming" of the LCD display. Maybe a better way to describe it is a loss > of contrast so that the numbers no longer appear different from the > background. > > A couple Fluke reps at a trade show immediately knew the problem (guess it > was common) and showed me what to do. The meter must be disassembled to the > point where the LCD glass can be removed. There are a couple rubbery > components that are apparently the (non-metallic) conductors to the LCD > glass. I'm not familiar with the construction technology, but they need to > be cleaned, perhaps with a swab moistened with alcohol. They may have used > a pencil eraser, I don't recall at this point. > > I just did mine a few minutes ago to prepare this response. This is > probably the third time this repair has been needed. The display had become {Quote hidden}> so faint that I haven't used it meter for some time. I hope yours is the > same thing, and is as easy to perform as on the 87 (which is now working > fine once again). > > Best wishes, > Randy Jones > > > ----- Original Message ----- > From: "Pic Dude" <.....picdudeKILLspam.....PILOTTOOLS.COM> > To: <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> > Sent: Saturday, August 10, 2002 11:57 AM > Subject: [EE]: Fluke meter LCD problem > > > > Got a Fluke 8060A DMM here, that has had an LCD problem since it was > > new. The LCD display is dim, and over time has dimmed more to the point > > where it's almost gone. I used to be able to see enough to use it, and it {Quote hidden}> > worked well otherwise. > > > > Any thoughts on what might be wrong, or how to go about analyzing this? > > I'm hoping that it's just a display connector or something simple. > > > > Cheers, > > -Neil. > > > > -- > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 01:24 PM 8/11/02 +1200, you wrote: >> The meter must be disassembled to the point where the LCD >> glass can be removed. There are a couple rubbery components >> that are apparently the (non-metallic) conductors to the LCD >> glass. > >Zebra strips > >Strange that this should happen to a quality product like Flukes. Yeah, it is strange but, well, you know, it's probably just a fluke. Tom M. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Contact enhancers would probably make all the segments turn on because of cross channel conductivity. Could also cause the rubber in the Zebra stripes to break down in time if the residue is the least bit oily (and most are, to act as an air barrier). The impedances involved are so high, anything the least bit conductive will give crosstalk. Be prepared to thoroughly clean off anything you apply if it does mess up the display. The long term problem with the displays may be inadequate clamping pressure. It only takes a few mils error in thickness to go from manufacturer's spec for pressure to 'too low to last'. I had this problem (Z-sripe fatigue) with several Beckman DVM's back in the 80's. Used a shim of paper under the plastic clamp to permanently (more or less) fix the problem. That might be an option for the Fluke's although the display clamp geometry is quite different. Robert Jim wrote: > > What would a touch of "Caig" contact enhancer > do I wonder? > > RF Jim > > {Original Message removed}

>Strange that this should happen to a quality product like Flukes. >I've used reasonable but cheap meters for years and never >needed to clean those conductors. Yeah... I've been using my moderately cheap meters with no problem, waiting for the motivation to dig into the Fluke. Glad this message came along, I have missed using it. I still have some of the Caig stuff, from back when they called it "Cramolin," but would be nervous about applying it to the Zebra strips. Especially given the long intervals between needing repair. In other words, it isn't enough of a pain to justify the possible risk, in my mind anyway. Can someone tell me what kind of conductor material is used in the Zebra strips? Some kind of carbon fiber or powder, maybe?? Robert, I had a Beckman DMM in the very early 80's... HD-100 maybe? It was the first bright yellow "hardened" handheld DMM, as I recall. The case halves were o-ringed, and it was rated for a multi-foot drop to concrete, and immersion in water. It gave me many years of good use in a tough environment (automotive electronics repair). Eventually the LCD developed the opposite problem as the Fluke -- the digit segments became dark even when the meter was off, and they gradually bled until the whole display looked like it was filled with black ink. Would that indicate a change in the spacing of the glass inside the LCD, or...??? Very nice meter, though. Randy -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Jim, Well, I have some Stabilant 22A, and both it and the Fluke were "evaluation" samples, so I guess I'm somewhat obligated to do some evaluation - heh, heh. We had considerable discussion and correspondence with D. W. Electrochemicals, the manufacturer of Stabilant, and I came away with a very positive impression. Stabilant has both a US patent and a NATO part number, and many positive testimonials from heavy-hitter sources. It is supposed to be non-conductive other than when in direct contact with a conductor, so.... gulp... here goes.... I took the 87 LCD back apart, and applied a very light coat of Stabilant 22A to the edges of the two Zebra strips which contact the main PCB. The strips were stuck fairly tightly to the LCD glass, and I wasn't comfortable pulling them off -- not knowing whether they are supposed to be that way. I seem to remember them *not* being stuck to the LCD earlier, but don't want to risk damaging anything. Reassembled... and... ugh... display is scrambled. But... the glass is upside down. Duh -- thought I was being careful to avoid that. Flipped it around and... beautiful. Definitely no cross-talk between the segments. The segments look darker than before, but I cannot be certain that the Stabilant is the cause: 1) Lighting conditions are a bit different than earlier when I first did the repair. 2) I disturbed the position of the Zebra strips again, which may have affected the contact resistance. 3) The influence of wanting a certain result? I'm trying to avoid this, but this is a subjective observation... Bottom line, the Stabilant didn't hurt (so far) and may well have helped. After completing the repair this afternoon, I was mildly disappointed at the lack of contrast, but thought maybe my memory of the original appearance was inaccurate due to the long time since the LCD has been working "as-new." Now it looks like new again. ...And if those three screws on the back would just stop trying to get cross-threaded, I'd be really thrilled! Oh... now I see why they're called "Zebra" strips. Anyone know what the conductive material typically is? Randy {Original Message removed}

At 10:51 PM 8/10/02 -0700, you wrote: >Oh... now I see why they're called "Zebra" strips. Anyone know what the >conductive material typically is? Alternating layers of conductive and non-conductive elastomer, typically silicone rubber. For LCDs, the carbon loaded stuff is okay (high resistance). There are alternative types that have lower resistance by the use of wires, but they don't seem to be very popular. I believe they were invented by a Japanese company. Personally, I prefer heat sealed flat cables for this kind of thing. The pin type is okay, but adds considerable cost to the display in quantity and constrains things mechanically. Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" speffspam_OUTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com 9/11 United we Stand -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Pic Dude wrote: > > Got a Fluke 8060A DMM here, that has had an LCD problem since it was > new. The LCD display is dim, and over time has dimmed more to the point > where it's almost gone. I used to be able to see enough to use it, and it > worked well otherwise. > > Any thoughts on what might be wrong, or how to go about analyzing this? > I'm hoping that it's just a display connector or something simple. If the effect is uniform over the entire display area you can probably rule out damage to the LCD elements and crystal material itself. Most likely the voltages going to the LCD are no longer correct. Since this "faded" over time my guess would be any caps in any inverter stages. That would be typical from the ESR faults etc that occur with caps over that time period. Check any electro caps in it, even the circuit mount ones. The surface mount caps in 10uF seem to fail a lot, they ooze a fishy smelling liquid. :o) -Roman -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Again courtesy of Malcolm Moore, here is where you can get manuals for the 8060A (hidden in "discontinued products" on Fluke's site) ftp://www.fluke.com/download/manuals/8060a_3vimeng0200.pdf ftp://http://www.fluke.com/download/manuals/8060a___imeng0300.pdf There is fairly large trucking firm here that is called "Fluke Transport"/ Their slogan: "If it's on time, it's a Fluke". Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" @spam@speffKILLspaminterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com 9/11 United we Stand -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Personally I use Stabilant 22a quite a bit. It really is a great product. I don't really know it works chemically, but it hasn't reacted with anything I've put it on yet. Just a satisfied customer, Josh -- A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams Jim wrote: > > Found this on a web search: > > "Stabilant 22A" > "Great for revitalization of LCD contacts" > > www.micro-tools.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=MT&P > roduct_Code=22A-F -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

At 09:46 PM 8/11/02 -0400, Spehro wrote: >Again courtesy of Malcolm Moore, here is where you can get manuals for >the 8060A (hidden in "discontinued products" on Fluke's site) > > ftp://www.fluke.com/download/manuals/8060a_3vimeng0200.pdf > ftp://http://www.fluke.com/download/manuals/8060a___imeng0300.pdf Spehro, THANK YOU! for that tip on Fluke. Having gone through the front door (dub dub dub....), I didn't find those files. But via ftp, there they are. Got 'em, checked 'em out, fixed my meter. Coool. I have a very old 8060A that had a leaky cap on the autozero portion of the a/d circuit. The pdf you linked to is very thorough and very friendly about how to open, troubleshoot and close-up the meter. Thanks again. Tom M. ps: don't hesitate to point out any other good test equipment manuals on line if you know of any, like Tektronix, HP, or others. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > The pdf you linked to is very thorough and very > friendly about how to open, troubleshoot and close-up the meter. This is why I really like Fluke. The way that they expect you to want to fix your own equipment, and seem to expect you to do so. For instance: the batteries are inside the main cover, not in a seperate compartment. There are no "do not open" or "no user serviceable parts inside" tags. - --Brendan -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.8 for non-commercial use <http://www.pgp.com> iQA/AwUBPVkt6QVk8xtQuK+BEQJNiwCgyLe3mG5S326JPVBRCaNMYlUKZj0AoL7f 1qsUI98CZeS26k1rU1hsBf37 =GnyW -----END PGP SIGNATURE----- -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email KILLspamlistservKILLspammitvma.mit.edu with SET PICList DIGEST in the body