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 ----- From: "Jim" To: Sent: Saturday, August 10, 2002 9:22 PM Subject: Re: [EE]: Fluke meter LCD problem > Found this on a web search: > > "Stabilant 22A" > "Great for revitalization of LCD contacts" > > http://www.micro-tools.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=MT&P > roduct_Code=22A-F > > Perhaps this is a specific application only to the particular > LCD they refer to ... proceed at one's own risk! > > RF Jim > > ----- Original Message ----- > From: "Robert Rolf" > To: > Sent: Saturday, August 10, 2002 10:15 PM > Subject: Re: [EE]: Fluke meter LCD problem > > > > 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 ----- > > > From: "Randy Jones" > > > To: > > > 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 > > > > 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" > > > > To: > > > > 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 > > > > > 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: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- 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