4 Jul
2004
4 Jul
'04
5:02 a.m.
On Sunday 04 July 2004 11:09, Dan Kolb wrote:
On Fri, Jul 02, 2004 at 04:33:23PM -0700, Michael
Sokolov wrote:
You could remove one power supply and then either crimp together a
splitter cable for one power supply, or just solder the connectors
together on the backplane...
Also, the power supplies, being switching supplies, need a minimum load.
Do you have boards on both halves (left/right) of the backplane? DEC
sold a "dummy load" board, which was a board with a bunch of resistors
on it, in systems that were "lightly" configured (didn't use most or
all of the left half of the backplane).
I'd recommending taking out a voltmeter and seeing if the system
voltages are "in tolerance" (within about 5% of their rating...
4.8-5.1V for 5V rail, 11.6-12.2V for the 12V rail, etc.)
Pat
--
Purdue University ITAP/RCS --- http://www.itap.purdue.edu/rcs/
The Computer Refuge --- http://computer-refuge.org
the CPU board, it may be the PSU. E.g., it's
out of tolerance and
does not assert the DCOK signal. Follow Tony's advice: check the
PSU voltages and the state of the DCOK signal before randomly
swapping parts (and certainly before rushing out to eBay to buy a
new KA655 board).
Interestingly, having moved the CPU boards to the left-hand side of
the chassis (it was originally on the right-hand side) allows the
machine to start up about 10-20% of the time, whereas before it
wasn't starting at all. Would each side of the backplane be connected
to a separate power supply? Would it be at all possible to run the
machine (BA213 chassis) with only one of the power supplies (I think
it's likely that the right-hand supply is slightly dodgy)?