21 Feb
2009
21 Feb
'09
7:37 p.m.
On Sat, Feb 21, 2009 at 7:41 PM, Rick Murphy <rick at rickmurphy.net> wrote:
If the cables between your power supply and the
backplane are ribbon cables
with IDC connectors, they can overheat (often you'll find them showing
discoloration.) If they're separate wires with white connector blocks, you
have the updated harnesses.
Confirmed.
I haven't seen this problem with BA23 boxes, but
have seen several BA123
boxes with signs of overheating.
We had a MicroVAX I that was FS-converted to a MicroVAX II ($20K,
IIRC, for boards, disk and license upgrades). When we finally traced
the acrid smell in the testing area, we found that the middle 25% of
the contacts on the IDC cable were charred, and, I think, the
connector housing itself broke apart when the cable was removed.
It may have helped that we had a totally-loaded BA23 since we needed
9MB of memory, serial, tape, *plus* room for our own 3rd party board.
There wasn't an empty slot in the machine.
The good news is that I still have that same machine and it still
works just fine 20+ years later, with the replacement DC power
harness.
-ethan