12 Nov
2005
12 Nov
'05
9:39 p.m.
Thanks for the hints, I was uncertain whether to use a continuity tester,
but it sounds safe.
I must have traced out over 100 boards in my life. I've always used a
continuity tester (firstly a homebrew one, then the Fluke 85), and have
never damaged anything. The chips on the boards have been a mix of TTL
(plain, L, H, LS, S, F, HC, HCT at least), 4000-series CMOS, NMOS and
PMOS LSIs, bipolar and FET-based analogue, etc (not all on the same
board, of course ;-)). AFAIK I've never damaged a single chip.
I would be wary if there were tunnel diodes on the board (from what I've
read, those are easy to damage), but I doubt that will be the case on
your boards.
The circuit boards are multi-layer and from what I can see, looking at one
side you can see writing on the layer below that says either +5 plane or
ground plane depending on which side you are looking at. I have never seen
this before, the buried ground and +5 buss, is this normal?
Yes, it've fairly normal to have the signal traces on the outside layers
and the power/ground planes inside.
-tony