chrismarseille wrote:Hi,
I managed to find a Frontier 2005 :) (not an 2005a) in a "sold for parts" watch ! Its works except the first digit :( so the base of this digit seems not connected (else I guess it´s a faulty driver or calculation iC?)
No corrosion on board links...I read in other posts about "dead digit" that it could come from "dry solder joints" between display and board but who knows which connection pad to check for the first left digit base ? I cannot see which circuit board wires go to the driver chip since chips are covered with black resin or silicone...
The one closest to this digit in the uppercut left corner (when facing the display) ?
If someone has a picture of this module without its protection resin, It also would help me :)
Thanks for reading
Chris
Hello Chris,
The "display stick" on Frontier modules were mounted using silver bearing epoxy,
they were not soldered. If the first digit, that is, viewing the display from left to right is completely out while all others are operational, its most likely the electrical connection from the substrate to the "ball" connection on the display stick, a bad epoxy joint. This would be the "K1" (common cathode) of the first digit. It could also be a broken wire bond from the digit driver to the substrate trace. Don't attempt to get to the digit driver chip which is under the black silicon rubber coating, you will definitely break several wire bonds for sure. Turn the display on in the "set" mode so that the first digit should be indicating a "1" or a letter, S,M,T,W,F and then apply a bit of pressure to the lower left side of the display. Bad epoxy joints will usually show up with pressure applied and go out when released. If this is the case, then all the wire bonds under the black blob are good and the fault is in the joint. The display stick can be "popped" off using the blade of a hobby knife with ease, putting it back on with conductive epoxy or "wire glue" (Google "wire glue" for info) is another story, one which I haven't read yet so to speak. Attached is the Monsanto data sheet showing the layout of connections for the display. I hope this will help you getting the module to work properly.
Joe
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