28 Sep
2014
28 Sep
'14
9:42 a.m.
I think the H214 is 8K x 16, and the H215 is the 8K x 18.
I thought about rerouting a few times, but never attempted it.
On Sat, Sep 27, 2014 at 11:59 PM, Josh Dersch <derschjo at gmail.com> wrote:
On 9/27/2014 2:11 PM, Tony Duell wrote:
Further investigation reveals that the connection
between FD1 on the
I'll double check things. My inspection is not made any easier by the
amount of dust covering this thing. I dare not attempt to clean it up, but
it makes finding faults visually pretty difficult.
card edge connector (the XS05 signal) and pin 7
of the 2501 at E22 is
broken. This, I believe, is a matrix wire (or "magnet wire" from the
engineering drawings) meaning that I've got a broken wire somewhere in
the core mat.
I would just trace the tracks, both visually an with an ohmmeter, from
the edge conector pin to the core mat and from the core mat to the diode
array. Just in case.
Incidneatlly, no matter what it says on the cover
over the core mat, you
can take it off quite easily without damage. Just don't drop it on the
corse.
If it is the core address wire in the mat, you may have big problems.
Some of these mats had the cores cast onto the array of wires, no
pre-made cores that were threaded with the wires. In which case,
replacing the wire might be impossible.
My first throught was 'have a go anyway. If you wreck the board, well, it
doesn't work now'. And then I thoguth that no, you should treat it with
care. Even if you don't have the skill to fix it now, you might do so i
nthe future. Or somebody else might have a go. In any case, you don't
want ot make thigns worse.
I do have a semi-crazy idea: The H214 I have is 8Kx18 bits (i.e.
parity). If I were to disable parity on the control boards and reroute one
of the parity-related lines for this damaged section, maybe I could get a
complete 8Kx16?
I'll have to do a bit more research...
- Josh
-tony