20 Nov
2014
20 Nov
'14
1:38 p.m.
Roe Peterson roeapeterson at gmail.com
I would remove all the boards, blow it out, insert the
minimum board
set, (CPU, memory, DL console, maybe bus terminator depending on
backplane) and just turn it on.
That long in storage, I think that I'd probably go for powering it on with a
dummy load first. It's not _that_ much more work, and it could save some
expensive/rare electronics.
It you don't have any QBUS Minimum Load Modules, get a couple of high-wattage
resistors (down at Radio Slack, if necessary) and rig the equivalent. The
M7556 MLM draws 1A of +5V, and I like to run two for testing. RS sells
10-Ohm/10-W resistors (ISTR they had smaller ones too, but I needed to test a
12V supply, hence the 10-W), so buy four...
Probably a good idea to throw a 'scope on the DC power, too, check for
ripple, etc.
Noel
20 Nov
20 Nov
5:09 p.m.
OK, decided to let the machine acclimate from 25 F to inside-house temps
overnight. The thing's still all together - RD54, TK50 with a tape in it
(!), Ethernet, DZ interfaces and TK25 interface plugs on rear.
Guess I'll be conservative, empty out the backplane and do the careful
powerup first. So where would I put the resistors? I still have my
wirewrap tool somewhere around here. Could try to figure out what pin is
the 5v rail and tie in a resistor on there, I guess. But I'd rather not
tear the thing apart *quite* so much if I could avoid it. Is there a way
to check ripple w/o a scope? (don't have one)
thx
jake
On Thu, Nov 20, 2014 at 4:38 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
wrote:
Roe Peterson
roeapeterson at gmail.com
I would remove all the boards, blow it out,
insert the minimum board
set, (CPU, memory, DL console, maybe bus terminator depending on
backplane) and just turn it on.
That long in storage, I think that I'd probably go for powering it on with
a
dummy load first. It's not _that_ much more work, and it could save some
expensive/rare electronics.
It you don't have any QBUS Minimum Load Modules, get a couple of
high-wattage
resistors (down at Radio Slack, if necessary) and rig the equivalent. The
M7556 MLM draws 1A of +5V, and I like to run two for testing. RS sells
10-Ohm/10-W resistors (ISTR they had smaller ones too, but I needed to
test a
12V supply, hence the 10-W), so buy four...
Probably a good idea to throw a 'scope on the DC power, too, check for
ripple, etc.
Noel
3689
days inactive
3690
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