%OP%JUY
%OP%PL52
%CO:A,56,56%%C%Eprom Checker - (c) S Marsh 25.1.89
 
%JR%The leaflet issued with the eraser states that after a 
%JL%while the efficiency of the eraser may be impaired and 
%JR%each EPROM may require more than one erase to clear it. 
%JL%If an eprom is not completely erased, then the Z88 will 
%JR%give an "UNABLE TO SATISFY REQUEST" message when saving 
to the area of EPROM which is affected.
 
%JR%This was happening to me, and I tried erasing EPROMs 
%JL%twice - without success. Investigation (with a 
%JR%microscope) revealed tiny particles resting on top of 
%JL%the EPROM inside the chip and I think that these were 
%JR%effectively shading parts of the EPROM from the UV 
%JL%light. A few sharp taps managed to dislodge these 
particles; my EPROMs now only need one erasure.
 
%JL%I have written a program to check whether all EPROM 
%JR%bytes have been reset to &FF after using the UV eraser. 
%JL%It is very easy to use, requiring only the number of 
%JR%pages (blocks of 16K) to be entered. The program is 
available from the User Club library.