Jeroni Paul wrote in message
...
N_Cook wrote:
Is there a special probe for doing this, thin , tough, insulated , with
graduations for indicating which row/column depth from the edge ?


I do not know, but it comes to mind you could use enamelled wire with the
insulation removed on a small area at one end. Drawing a small scale on the
wire may be the hardest part but if you are interested in just a few pins
that reduces the number of marks to place.


+++++
I have some .08mm tungsten wire that is just about stiff enough as a probe ,
for this Ti ADP2000 BGA could have been larger diameter, laquered over and
just the end ground down clean. A refinement I suppose would be contrasted
markings along the laquer for row/column spacings, I think up to 5 deep in
some areas of these