17 Mar
2011
17 Mar
'11
3:38 p.m.
I have a MicroVAX 3100 Model 95 (KA51) which seems to be damaging my SIMMs.
It will work for a while and then one or more SIMMs will fail. The failed
SIMMs have always been in SET 0. Sometimes it has been just one SIMM, this
time it seems to have been the whole set of 4.
Is it really possible for the CPU to do this?
Anyone got a KA51 they don't want?
Regards
Rob
17 Mar
17 Mar
3:53 p.m.
In article <008201cbe4f4$153cf260$3fb6d720$(a)ntlworld.com>om>,
"Rob Jarratt" <robert.jarratt at ntlworld.com> writes:
Is it really possible for the CPU to do this?
Bad voltage supplies or current surges can damage any parts. Have you
checked that the PSU is operating within specification? Have you
checked for signs of aging capacitors?
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4:08 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Richard
Sent: 17 March 2011 22:53
To: cctalk
Subject: Re: MicroVAX 3100 Model 95 Damaging SIMMs?
In article <008201cbe4f4$153cf260$3fb6d720$(a)ntlworld.com>om>,
"Rob Jarratt" <robert.jarratt at ntlworld.com> writes:
No I have not, sounds like that is my next step, although I don't think I
have the equipment to check if the PSU is operating to spec, I can visually
check components. I won't be switching the machine on again until this is
resolved as I am losing memory modules at an unpleasant rate.
Thanks
Rob
Is it really possible for the CPU to do this?
Bad voltage supplies or current surges can damage any parts. Have you
checked that the PSU is operating within specification? Have you checked
for signs of aging capacitors?
--
"The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
<http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/>
Legalize Adulthood! <http://legalizeadulthood.wordpress.com>
7:56 p.m.
In article <008301cbe4f8$36678f50$a336adf0$(a)ntlworld.com>om>,
"Rob Jarratt" <robert.jarratt at ntlworld.com> writes:
No I have not, sounds like that is my next step,
although I don't think I
have the equipment to check if the PSU is operating to spec, I can visually
check components.
Supply voltages can be checked with a simple voltmeter. With dummy
resistor loads on the PSU you can check current supplied by measuring
the voltage across the resistor load.
--
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<http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/>
Legalize Adulthood! <http://legalizeadulthood.wordpress.com>
25 Mar
25 Mar
4:22 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Richard
Sent: 18 March 2011 02:56
To: cctalk
Subject: Re: MicroVAX 3100 Model 95 Damaging SIMMs?
In article <008301cbe4f8$36678f50$a336adf0$(a)ntlworld.com>om>,
"Rob Jarratt" <robert.jarratt at ntlworld.com> writes:
I have just been checking the outputs from the PSU and was wondering how
"good" they are. Here is what I measured:
On the standard Molex connector the 5V output is around 5.3V, the 12V output
is pretty much dead on. On the CPU power connector I measured these
voltages:
5.0V
5.3V
5.3V
-12.46V
-5.98V
5.31V
12.04V
5.31V
I am not sure what the nominal voltages are supposed to be on this connector
(the -5.98 looks a bit suspicious) and how much out of tolerance they are.
How do these voltages look?
Regards
Rob
No I have not, sounds like that is my next step,
although I don't
think I have the equipment to check if the PSU is operating to spec, I
can visually check components.
Supply voltages can be checked with a simple voltmeter. With dummy
resistor loads on the PSU you can check current supplied by measuring the
voltage across the resistor load.
--
"The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
<http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/>
Legalize Adulthood! <http://legalizeadulthood.wordpress.com>
4:52 p.m.
-----Original Message-----
From: Rob Jarratt [mailto:robert.jarratt at ntlworld.com]
Sent: 25 March 2011 23:22
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: MicroVAX 3100 Model 95 Damaging SIMMs?
Actually I just found some info on the PSU label, it says
V1 +5.1V
V2 +12.1V
V3 +3.3V
V4 -12 V
V5 -9V
Some of the voltages I measured are a long way from that. I certainly did
not measure 3.3V or anything close anywhere. Of course I am not sure which
of the pins I measured should be 3.3V and little clue which one it might be
except perhaps for the one that I measured at 5.0V which is only because it
is numerically closest. Should I be looking at replacing capacitors as
suggested, would that be the cause, or is it going to be something else
entirely? Having inspected the capacitors there is no *visual* sign of
anything wrong.
Thanks
Rob
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Richard
Sent: 18 March 2011 02:56
To: cctalk
Subject: Re: MicroVAX 3100 Model 95 Damaging SIMMs?
In article <008301cbe4f8$36678f50$a336adf0$(a)ntlworld.com>om>,
"Rob Jarratt" <robert.jarratt at ntlworld.com> writes:
I have just been checking the outputs from the PSU and was wondering how
"good" they are. Here is what I measured:
On the standard Molex connector the 5V output is around 5.3V, the 12V
output is pretty much dead on. On the CPU power connector I measured
these voltages:
5.0V
5.3V
5.3V
-12.46V
-5.98V
5.31V
12.04V
5.31V
I am not sure what the nominal voltages are supposed to be on this
connector (the -5.98 looks a bit suspicious) and how much out of tolerance
they are. How do these voltages look?
Regards
Rob No I have not, sounds like that is my next step,
although I don't
think I have the equipment to check if the PSU is operating to spec,
I can visually check components.
Supply voltages can be checked with a simple voltmeter. With dummy
resistor loads on the PSU you can check current supplied by measuring
the voltage across the resistor load.
--
"The Direct3D Graphics Pipeline" -- DirectX 9 draft available for
download
<http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline
/>
Legalize Adulthood! <http://legalizeadulthood.wordpress.com>
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