22 Jan
2017
22 Jan
'17
2:12 p.m.
On 01/22/2017 01:49 PM, Maciej W. Rozycki wrote:
A problem with reworking is there is sometimes very
little clearance
available, so any modification has to be made in a clever way or you
risk a short-circuit. For example in DECstation 5000 systems their
DS1287 chip is located in the TURBOchannel option slot area with the
top of the chip almost reaching the solder side of the PCB of any
option plugged in there.
Although there are several illustrations of the DS1287 rework where a
coin-cell holder was placed atop the chip, there's absolutely no reason
why that has to be so. A couple of wire leads away to an off-board
battery holder, holding, say, an ER14250 half-AA.will work just fine and
keep the battery away from the PCB--or a couple of alkaline AA cells,
which should last a few years. No reason to stick to lithium.
You know--"use your wetware".
--Chuck