streeter@theory.lcs.mit.edu (Kenneth B Streeter) (04/23/91)
I have recently received a Model 100. Before being shipped, it worked flawlessly. Now, however, it doesn't work properly. When it is turned on, most of the time, the display goes all black. Occasionally, however, when it is turned on, the display shows the menu as it should, but then after from 1-5 seconds, the display goes back to being all black and remains that way. The menu is more likely to appear for 1-5 seconds if the "memory switch" was turned off/on as well. Has anybody seen this type of failure mode before? Any suggestions? -- Kenneth B. Streeter | ARPA: streeter@im.lcs.mit.edu MIT LCS, Room NE43-350 | UUCP: ...!uunet!im.lcs.mit.edu!streeter 545 Technology Square | (617) 253-2614 (work) Cambridge, MA 02139 | (617) 225-2249 (home)
cameronjames@snoc01.enet.dec.com (James Cameron) (04/23/91)
In article <1991Apr22.170558.9330@mintaka.lcs.mit.edu>, streeter@theory.lcs.mit.edu (Kenneth B Streeter) writes: > I have recently received a Model 100. Before being shipped, it >worked flawlessly. Now, however, it doesn't work properly. When it >is turned on, most of the time, the display goes all black. >Occasionally, however, when it is turned on, the display shows the >menu as it should, but then after from 1-5 seconds, the display goes >back to being all black and remains that way. The menu is more likely >to appear for 1-5 seconds if the "memory switch" was turned off/on as >well. No, I haven't seen this type of failure before, but I can offer a guess as to what may be going on. Firstly, I assume that "display goes all black" means "display goes blank". I admit that this is a rather obtuse assumption... If the memory backup battery is dying, then this is likely to be the sort of problem you would experience. Or, if you are running on nearly dead batteries, sometimes the low battery light doesn't come on and it just shuts down. Try supplying 6.5VDC to the power supply connector. The documentation does state that the memory backup battery is charged from the current power supply during operation, and that if you leave the machine unused for a time it may lose the memory contents. If the machine experienced a physical shock during shipping, I guess it may have done something to the memory backup battery connections. I can't remember clearly, since it is a while since I last had my 102's open, but I think that the battery is a bit bigger than most things on the PCB, elevated slightly, and is therefore more than likely to suffer from damage induced by physical shock. Now, assuming that the display does go all "black"... I guess it could be the same sort of thing with the battery. Though what would cause the LCD controller to set all pixels is beyond me. Have you used that little dial on the right hand side to adjust the viewing angle of the LCD? I guess a failure of this dial could also cause apparent total blackness. -- James Cameron Digital Equipment Corporation (Australia) P/L (cameronjames@snoc01.enet.dec.com)