HP Forum Archive 19

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16C display problem Message #1 Posted by John Robinson on 7 June 2010, 7:45 a.m. Hi All, I have a 16C which had a leaky display, so I bought a 12c of the same vintage (1984) as a display donor. The 12c display was working perfectly, so I swapped out the 16c old display for the new 12c display, and after various attempts I have it working as best I can. However, one segment in one digit refuses to work. I would have though these displays would be multiplexed, so if one segment doesn't work, then that same segment in all digits would not work. I have counted the number of contact pads for the siplay to be 57, which would not be enough to individually address all 7 segments and decimal point for 10 digits and annunciators etc, so I figure it must be multiplexed. Can anyone help me to sort out this problem please ? Thanks John

Re: 16C display problem: thatīs new! Message #2 Posted by Vieira, Luiz C. (Brazil) on 7 June 2010, 9:15 a.m., in response to message #1 by John Robinson Hi; I have swapped some Voyagerīs displays but never had such problem before. In time: can you take a picture OR indicate which segment is the one refusing to 'lit'? Sorry not helping the way I would like to... Thanks and success! Luiz (Brazil)

Re: 16C display problem: thatīs new! Message #3 Posted by John Robinson on 7 June 2010, 7:12 p.m., in response to message #2 by Vieira, Luiz C. (Brazil) Hi Luiz, I have it working now. I have been doing this with the display and metal surround as one unit. So coming in at an angle to install one edges four clips, then bring down the other edges clips. The results seem very much dependant on how well seated the display zebra strips are. I just kept on re-seating the display unil it worked. It's just a little tricky installing the display on one edge with the metal clips, then do the other edge, but by then then zebra strip on the first edge is not seated correctly. I realise I could have removed the metal surround, and placed the display flat on the circuit board, then slid the metal surround over and push the clips through the holes. Maybe that's the better way to do it to avoid problems like missing segments. Cheers, john

Re: 16C display problem: thatīs new! Message #4 Posted by Vieira, Luiz C. (Brazil) on 7 June 2010, 10:26 p.m., in response to message #3 by John Robinson HI; I use a long sewing needle to seat the zebra stripe correctly. The needle helps aligning it, either from the inside or the outside of the zebra stripe. If you look at the LCD assembly from the extreme edges, youīll notice small cuts in both sides of the metal frame where the zebra stripes end. This is where I carefully insert the needle and align the zebra stripe accordingly. I also came to the conclusion that placing the metal frame after the LCD + stripes works better. Unfortunately I had nothing but bad results with the early models with the flex circuit assembly... Cheers. Luiz (Brazil) Edited: 8 June 2010, 8:03 a.m.

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