30 Jul
2001
30 Jul
'01
3:51 p.m.
On 30 Jul, Ethan Dicks wrote:
I have a small box of dead NVRAM chips (48T02 from
various sun4c machines).
A SPARCstation 1+ was my entrance to this kind of surgery.
:-)
Are there any components other than the battery in the
potted lid?
Yes. At the side of the pins 1 / 24 is the quartz. The battery is at
the
side of the pins 12 / 13.
i.e., can I just remove it entirely or
NO! (Or
you have to reattach the quartz.)
do I have to perform delicate surgery to seperate the
front leads and solder
wires onto the front of the I.C. where the lid used to connect?
This is more ore
less the case. You have to mill into the resine from
the top down to the top of the battery. You need to remove about 5 to
8mm from the pin 12/13 edge towards the pin 1/24 edge. Prepare the top
of the battery so that you can see the wire that goes down to the chip.
This is +. Carefully mill down that wire up to the gap between the led
and the chip. Free the wire from the resine left and right of it. Cut
the wire at the top from the battery. Solder a wire to it and to the +
connector of a 3V battery. Connect - of the battery to pin 12 (GND) of
the chip. You can connect - of the new battery to the - wire of the old
battery. But that wire is very short and therefore difficult to prepare.
As it is directly connected to pin 12, it is better to use that to
connect - of the new battery.
You can also use rasp to take the top of the led away up to the top of
the battery. Then you can use a sharp cutter knife to prepare the +
wire. But you need to be more careful when using this method than with
a mini drilling machine and you need some more detaild knowledge of the
anatomy of the chips.
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/