I have an old Fluke multimeter (8022B) which is still serviceable. Unfortunately, part of the LCD display has a blackened area, which obscures the =/- signs. The black area is always visible, even with the instrument switched of. Is there any way to correct this problem? The cost of replacing the display would be prohibitive, even if I could source one and I could probably buy another Fluke from eBay quite cheaply.
Terry D.
In article , Terry D scribeth thus
Got a couple of 8050 A's one of which has this problem now somewhere on the net is an article on how to make them replacement LED and it wasn't at all difficult..
Dammed if I can remember where I put the URL now!..
a goggle search might show it up..
It is not possible to correct a display that has failed in this way. We used to sawp them out at work for new ones but our stocks are long gone as this was a regular fault. Getting a spare from a otherwise faulty one on ebay would be a good way to go. You might find it worth while to find the partnumber of your display and see if it is used in other flukes of a similar vintage to give you a wider range to target on ebay. I have an 8020 which I'm pretty certain has the same display. A brief search has not turned up my manual so I can't give you the part number to compare.
Good Luck
Bob
Found it! Part number is 453100 on at least 8020 and 8022 possibly loads more. Manual download for old models here.
If you are confident with some simple electronics, then you could perhaps add a single LED to replace the sign segment. you need to locate the sign segment drive and the backplane (common) on the display. these are both squarewave signals and when in pahse the display is blank and out of phase the display is black. Use a CMos exlusive-or gate to drive a transistor to switch a LED. Bear in mind that the dvm chip will have no significant drive capability and is easily damaged.
hth
Bob
Thanks for the info - I've downloaded the manual. Actually the LCD part no. for the 8022B is 504324 according to the manual. Somehow I don't think I stand much chance of obtaining a replacement, although I'll keep watching eBay.
Terry D.
Ah! I was looking at the 8022A. Bob
Terry D wrote on 24/11/2007 :
I once had some success by warming the display such that I made it warmer towards the centre combined with light finger pressure squeezing the black out towards the edge. Something a bit hotter than an hair dryer, but not so hot as a hot air gun is best. I then sealed the edge of the display.
Terry D.
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