[comp.sys.att] flaky 3b1

pusateri@macbeth.cs.duke.edu (Thomas J. Pusateri) (03/08/90)

I'm having some weird symptoms with my 3b1 and was wondering if any
one else had similar problems.

I'll be typing along and all of a sudden everything will freeze. The
heartbeat LED stops and nothing works. When I cycle power on the machine,
it doesn't ever get past the rom initialization. Usually the LEDS stop
at the first stage with just the red LED on but occasionally it gets
to the GREEN led.

This happenned once before and I took the machine completely apart and
put it back together and it worked okay again.

This only started happenning after I connected an epson rx-80 to the
parallel port. It happenned the first time with the 3.51a kernel and
this most recent time with the 3.51m kernel. It never happened with
the 3.51 standard kernel.

I love the machine but I have to admit, its not very reliable. By the
way, I don't have any power protection on the machine. I've been told
the cheapo surge supressors are junk and can't afford a good power
line conditioner yet.

Any suggestions would be appreciated.

Tom Pusateri
Duke University Medical Center
pusateri@nbsr.duke.edu

kevin@kosman.UUCP (Kevin O'Gorman) (03/09/90)

In article <18039@duke.cs.duke.edu> pusateri@macbeth.cs.duke.edu (Thomas J. Pusateri) writes:
>I'm having some weird symptoms with my 3b1 and was wondering if any
>one else had similar problems.
>
> [description of flakiness]
>
>This only started happenning after I connected an epson rx-80 to the
>parallel port. It happenned the first time with the 3.51a kernel and
>this most recent time with the 3.51m kernel. It never happened with
>the 3.51 standard kernel.
>
>I love the machine but I have to admit, its not very reliable. By the
>way, I don't have any power protection on the machine. I've been told
>the cheapo surge supressors are junk and can't afford a good power
>line conditioner yet.

I also was having a bunch of 'flakiness' on my 3b1.  It would come and go,
and I would wonder if it was related to the most recent slight alteration
to what was going on or what was connected.  It had built up over time,
so I got used to it, but finally got worrisome enough that I posted a
message much like yours.  I got about 3 replies, all suggesting a power
supply problem.  I have surge protectors, but that's all.

Well, I had bought a couple of spare supplies and had never installed them,
so I did it right away.  This machine has been up solid now for two
months, and looks just plain bulletproof.

Alerted to this, and paying attention to other traffic on the net, I have
come to the conclusion that all sorts of off-the-wall troubles can be
caused by a weak 3b1 or 7300 supply.  Try to get a spare, or just get
someone who knows how to work on your existing supply.  They are almost
always repairable.


-- 
Kevin O'Gorman ( kevin@kosman.UUCP, kevin%kosman.uucp@nrc.com )
voice: 805-984-8042 Vital Computer Systems, 5115 Beachcomber, Oxnard, CA  93035
Non-Disclaimer: my boss is me, and he stands behind everything I say.

scj@casux4.uucp (Steve Johnson) (03/12/90)

In article <1137@kosman.UUCP> kevin@kosman.UUCP (Kevin O'Gorman) writes:
...
>
>Well, I had bought a couple of spare supplies and had never installed them,
>so I did it right away.  This machine has been up solid now for two
>months, and looks just plain bulletproof.
>
>Alerted to this, and paying attention to other traffic on the net, I have
>come to the conclusion that all sorts of off-the-wall troubles can be
>caused by a weak 3b1 or 7300 supply.
...

I don't think that Kevin missed this himself, but for those out there
that plan to replace their power supplies, remember to check out those
voltages carefully when you install.  Both of the 3B1 power supplies I
bought recently were badly out of trim (How about +4.3V & +10.5V). 
Prior postings cover the voltage & pinout assignments, email to me if
you want a copy.

___
Steven C. Johnson, Bell Communications Research, Inc.
{scj@casux4.custom.bellcore.com (128.96.153.2)} or {bellcore!navaho!scj}