2 Mar
2008
2 Mar
'08
10:45 a.m.
Subject: Re: VAXstation/MicroVAX 2000 CPU/FPU overheating?
From: "Dave Dunfield" <dave06a at dunfield.com>
Date: Sun, 02 Mar 2008 09:35:46 -0500
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
Aw, I wish ... the only things socketed on this board are the ROMs and
the serial device. The CPU/FPU are 68 pin surface mount devices.
It doesnt other than not jamming the busses. VAX does nto need the FPU
to boot.
The
extended system tests 101, 102 and 80000106 will not test the FPU
- this may be normal, I don't know. The docs say they will test all
hardware which is installed - this may mean that the FPU is not being
full detected... I don't know.
Is the FPU socketed? If so, can you remove it, and what the boot and
test output looks like? If you can't remove the FPU (likely), the
diagnostics would probably be
complaining about it not working...
Which is the main reason I'm not 100% convinced the FPU is faulty. But I
can't get the extended disgnostics to test it, and I don't know how
"good"
it has to be to pass the basic startup test. I've not had my uV2000 opened up (or even
turned on yet...), but that'd
be my next step.
Maybe if I have some time, I'll dig mine out and try playing with it.
If you do open it up and have it to the point where you can scope signals,
please contact me ... I've got a few questions about the signals I see in
mine. I've also got a couple of questions about the diagnostics and the
FPU that could be answered with a running system (only the console ROM
required).
If anyone has a running VS2000 or UV2000 and is willing to open it up to
help me do some comparison testing, here are the things I would most like
to know: [For best results, it would be good if the system were
configured to match
mine - all expansion boards, drives, peripherals etc. disconnected, and
the uVAX/VS jumper located about 3" directly behind the BNC ethernet connector
set to the uVAX position, which is AWAY from the BNC connector.]
Sounds like mine more or less. I cant scope it at this time as the wide
band scope is burried and likely not going to emerge for a while. I
have a 20mhz dual trace for most work handy as it's smaller but it
will not see a 40mhz clock well nor do I use it for that kind of work.
Allison
[To run the extended diagnostics 101, 102 and 80000106
you need a DB-25-F
connector installed (on the DB-25-M connector on the board) with pins 12
and 18 connected together]
a) Whats tests are run by the "T 101" command?
Mine runs: C, B, 7, 6
b) If you run "T 80000106" and then enter '9' at the "?
>>>" prompt,
do you get any test output other than the CPU designation title?
[For the following, I would like a description of the waveforms
observed, waveshape, amplitude and frequency where appropriate]
c) The 40Mhz clock at the W4 jumper (right beside the 40Mhz oscillator
"can") - with the jumper installed?
I see 40Mhz sine wave, about 2.3v p-p
d) The 40Mhz clock at the W4 jumper pin closest to the oscillator
"can" with the jumper removed?
I see 40Mhz sine wave about 3.4v p-p
e) Pins on FPU
44 - I see about 160mv irregular square wave
59 - Same as above
15 - I see 40Mhz at about 160mv
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html