This means I could erase the 509 with some patience and a shiny day !! Thanks for all your replies Javier -----Mensaje original----- De: Dr. Imre Bartfai Para: PICLIST@MITVMA.MIT.EDU Fecha: Viernes 24 de Septiembre de 1999 04:18 a.m. Asunto: Re: Erase 12c509 with Sun >Hi, >your experiment was unsuccessfull, because of normal window glasses filter >the UV component out. That's why EPROM's have special quartz window. A >direct exposure can tamper the EPROM's content in less than one hour I >guess (at least at us, in a Summer Noon). > >Regards, >Imre > > >On Thu, 23 Sep 1999, Keelan Lightfoot wrote: > >> >Is it possible to erase a windowed PIC with sun light ?? >> >How much do I have to wait ? >> >Bye and thanks >> >> Yes, it is possible. For EPROMs (27xxx series), some datasheets state that >> erasure in the sun requires 1 week of constant direct exposure. I left a AMD >> 2732 EPROM in a south facing window for 2 months, and nothing changed. An >> intel datasheet says "constant exposure to room level fluorescent lighting >> could erase the EPROM in approximately 3 years." >> >> I finally broke down and bought a $150 canadian EPROM eraser, that can eat >> about 20 EPROMs at a time, meaning about 80 8 pin PICs at a time. >> >> If you are looking for alternative erasure methods, have a look at: >> http://www.intermarket.net/~don/uvbulb.html >> >> - Keelan Lightfoot >> >>