pelegri@RENOIR.BERKELEY.EDU (Eduardo Pelegri-Llopart) (04/24/87)
I just bought a cheap quartz clock with an LCD. It is one of those smallish units that you can stick on your refrigerator, desk, or whatever, and has mode/set buttons. I have had similar clocks before - in a different package - so I assume the internals are all the same. I know little of electronics, so here goes the description of my problem as far as I can see it. The clock works fine except that, whenever I place it in direct sunlight it turns itself off. I.e. it is not that the display goes blank, but the clock resets itself too. This seems equivalent to what happens if I take the battery off. The behaviour is reproduceable and it does the same thing when close to an incandescend (sp?) light bulb. The battery seems fine, I had it checked out. I took the clock appart and it there seems to be nothing loose. There is a single board with contacts for the set/mode buttons, something that has to be the quartz what-ever, and contacts leading to the upper side of the board, where there is a connecting white plastic bar, with some black (i guess conducting) inserts going to what seem to be the "in" contacts in the LCD. The reaction to the sunlight is pretty fast, and somewhat cumulative: it takes ~3 secs at the beginning, and later it can be on 1 sec or less. Since I wanted the clock to place on the stem of my bicycle, removing it from direct sunlight is not a solution :-). Besides, I am pretty curious. suggestions?- thanks- eduardo p.s. Sorry for the length of this.
wtm@neoucom.UUCP (04/30/87)
Perhaps the cheap LCD clock shuts down when placed in the sun is due to heating. In some cheap units the LCD connets to the PC board though a flexlible plastic strip with carbon fibers imbedded in it. If the parts heated at uneven rates, the connection to the battery might be lost. Just a thought... --Bill