Path: utzoo!attcan!uunet!decwrl!wuarchive!zaphod.mps.ohio-state.edu!tut.cis.ohio-state.edu!pt.cs.cmu.edu!dsl.pitt.edu!pitt!jcd
From: jcd@pitt.UUCP (Jim Durham)
Newsgroups: comp.sys.dec
Subject: More MVII Hardware Help
Keywords: DZV11, Serial Ports, SLIP
Message-ID: <8810@pitt.UUCP>
Date: 9 Oct 90 16:43:35 GMT
Organization: Computer Science Dept., Univ. of Pittsburgh
Lines: 37

Thanks to all who replied to my inquiries concerning the TK50/RQDX2
problems I have been having. That conversation has taken off in
a slightly different direction, but is still good reading.

Here's my latest dilemma with my "used" MVII 8-) : I have
a need for a SLIP link to another computer. I have two AVIV SDZV11
8 port serial cards, which are supposed to emulate the Dec cards.
WHen running SLIP or just Kermiting to the other machine, the
whole serial system just dies at random times. It seems to be
that the incoming data is lost. If I ping the other machine, the
Microvax sends, but does not receive the reply. This also happens
when running Kermit, so it doesn't appear to be a SLIP driver
problem.

I have tried both cards, and the results are identical. Sometimes
I can move a 100k file and sometimes I can't get 5 characters between
the machines. All 8 ports die together. A terminal on tty00 will die
also if SLIP on tty02 dies.

This sounds like an input buffer problem to me. By the way, this
is Ultrix 3.1 . Oh yes, the only way to restore the serial system
is to reboot. Any ideas?

Incidentally, for those of you to whom old MVII's are starting to
filter down, let me reiterate my first two hassles with this machine.
First...keep the VR260 monitor *cool*. The flyback in this monitor
is capable of blowing with any kind of heat. I know. Second...if
the MVII is dusty, check the voltage on the bus. The connectors from
the power supply to the bus are cheesy and you can get over a volt
of drop in the +5 supply. TTL doesn't work well on 4 volts. I've
been through this one, too. If you have an extender card, pull
some module, put it on the extender, and measure with a digital
voltmeter from ground to +5 on some chip. If you don't have
at least 4.9 volts, better clean up the power suppply/bus connectors.
I hope this helps someone to not lose as much cranial hair as I did.

-Jim Durham