HD trouble?

"Bill Cunningham" schrieb im Newsbeitrag
...

"Paul" wrote in message ...

The ESD wrist strap, is for safely helping to bring things to the
same potential (equipotential). Yes, it is a better solution while
working on the computer, than zapping things with your fingers.
At one time, a RAM purchase may have included a paper (disposable)
wrist strap. Having your own proper wrist strap, means being
able to reuse it at a future date.

Is there any way to run a voltage or continuity test with a multi meter
on the ram sticks? To see if they're good.

Bill

No, there isn't. Attacking a memory stick with a multimeter is equivalent to
tapping your skull with a hammer. It may ring but you won't find out if it
functions normally.

Bill Cunningham wrote:
"Paul" wrote in message ...

The ESD wrist strap, is for safely helping to bring things to the
same potential (equipotential). Yes, it is a better solution while
working on the computer, than zapping things with your fingers.
At one time, a RAM purchase may have included a paper (disposable)
wrist strap. Having your own proper wrist strap, means being
able to reuse it at a future date.

Is there any way to run a voltage or continuity test with a multi meter
on the ram sticks? To see if they're good.

Bill


I can't think of any good tests. If you're seeing just a few errors
for example, that suggests exterior (visible) electrical issues aren't
the problem, and the problem is inside one of the RAM chips. If the module
gave a clean failure in some way, then you might deduce from that,
that there was an open series damping resistor or a bad solder joint.
But the majority of failures are going to involve something inside
the RAM chip. So the multimeter doesn't tell us a lot.

Paul

Pegasus [MVP] wrote:
"Paul" schrieb im Newsbeitrag
...
Bill Cunningham wrote:
"Paul" wrote in message
...

The ESD wrist strap, is for safely helping to bring things to the
same potential (equipotential). Yes, it is a better solution while
working on the computer, than zapping things with your fingers.
At one time, a RAM purchase may have included a paper (disposable)
wrist strap. Having your own proper wrist strap, means being
able to reuse it at a future date.

Is there any way to run a voltage or continuity test with a multi
meter on the ram sticks? To see if they're good.

Bill


I can't think of any good tests. If you're seeing just a few errors
for example, that suggests exterior (visible) electrical issues aren't
the problem, and the problem is inside one of the RAM chips. If the
module
gave a clean failure in some way, then you might deduce from that,
that there was an open series damping resistor or a bad solder joint.
But the majority of failures are going to involve something inside
the RAM chip. So the multimeter doesn't tell us a lot.

Paul


The multimeter test might destroy the RAM chip, like the tap on the head
with the hammer. I find it difficult to think of a more inappropriate test
for a RAM chip. Remember - it contains a hundred million or more
transistor
gates operating at extremely low currents, less than the most sensitive
multimeter can detect!

Beyond that, it's the wrong tool for the job, no matter how sensitive it is.

There is no way a multimeter could test an integrated circuit. What would
be needed is an IC tester, and that would be specific for that type of chip,
as there is no such thing as a universal IC tester.

The only practical way to test a suspected IC chip for a consumer would be
by substitution with another one to see if that works.

Pegasus [MVP] wrote:


The multimeter test might destroy the RAM chip, like the tap on the head
with the hammer. I find it difficult to think of a more inappropriate
test for a RAM chip. Remember - it contains a hundred million or more
transistor gates operating at extremely low currents, less than the most
sensitive multimeter can detect!

You can safely test silicon devices, if you use a multimeter with
"low power ohms" setting. It applies a voltage not intended to
cause forward conduction in the silicon chips.

If you lost the manual for your multimeter, you can verify this by using
two multimeters. One multimeter set to "ohms". The second multimeter
set to "volts". The "volts" multimeter will show you a rough idea
of the open circuit voltage that the "ohms" meter is putting out.
(Connect red to red, black to black.)

Test all the "ohms" ranges on the meter, to understand which
ranges are "high power" and "low power". If an ohms range doesn't
put out more than 1 volt open circuit, then it should be relatively
safe to use on just about anything. For the highest resistance
ranges, the results need some interpretation (since the voltmeter
has a finite input impedance of its own)

The $100 The $20
meter meter

Range Ohmmeter Voltmeter Assumed Confidence
Reads Reads Power type

Beep Infinity 2.66V High
Diode infinity 2.67V High High on purpose, for diode test
200 Infinity 1.01V Low
2K infinity 1.01V Low
20K Infinity 0.48V Low
200K infinity 0.43V Low
2M "0.995" 0.23V Low OK, see interpretation
20M "0.99" 0.04V Low
2000M "001" 0.27V ??? suspicious

(Note - a separate set of tests were done, and the "ohms" multimeter
never applied more than 1 milliamp of current to the test leads. Typical
silicon clamp diodes are rated for about 10 milliamps. So there is
no danger from the level of current flow either.)

In the 2 megohm test case, the "volts" multimeter appears to
have only a 1 megohm input impedance. Half of the open circuit
voltage is across the "volts" multimeter, and half is across
the constant current source inside the meter. We could conclude
from that, that the actual open circuit voltage applied
by the multimeter, is 2 * 0.23 volts or 0.46V. And that is suitable
for low power ohms. So you actually have to stare at the display
on both devices to understand what is going on.

My suspicion is, the "insulation test" range on my multimeter, is
actually high power ohms. It is pretty hard to test insulation,
with a low voltage. Insulation testing would normally be done
with a "megger". Since I am suspicious of what I see for the
2000M range, I likely would not switch to it while working on
the average PCB.

There are quality voltmeters, with much higher input impedance
than my $20 "volts" multimeter used in this test. For such a
device (perhaps a $1000 unit), I likely would not need interpretation
except for the last test case. And the voltmeter in that case, could
tell me what the open circuit voltage is, correctly, for the
rest of the ranges.

The $20 meter is the one I lend to friends :-)

So there are six ranges on my $100 multimeter, that I'd use on a DIMM.
Without being concerned about any side effects to the silicon.

Some older meters, like my analog Simpson, are a bit meaner.
They apply nine volts open circuit, and would be unsuited
for this purpose. I could have run the same set of tests for
my Simpson, but there is no point, because I simply wouldn't
use it. My Simpson is good for volts "trend analysis", as digital
meters aren't perfect for all purposes. There are still
occasions for reaching for my oldest multimeter. "Ohms" would
not be one of those reasons.

If a person had concerns about any silicon device they were
working on, they could look in the datasheet for inspiration.
I haven't done that in this case for the memory chip. I'm reasonably
confident, that the six tested ranges on my multimeter, would
be safe enough.

HTH,
Paul

"Paul" schrieb im Newsbeitrag
...
Pegasus [MVP] wrote:


The multimeter test might destroy the RAM chip, like the tap on the head
with the hammer. I find it difficult to think of a more inappropriate
test for a RAM chip. Remember - it contains a hundred million or more
transistor gates operating at extremely low currents, less than the most
sensitive multimeter can detect!

You can safely test silicon devices, if you use a multimeter with
"low power ohms" setting. It applies a voltage not intended to
cause forward conduction in the silicon chips.

If you lost the manual for your multimeter, you can verify this by using
two multimeters. One multimeter set to "ohms". The second multimeter
set to "volts". The "volts" multimeter will show you a rough idea
of the open circuit voltage that the "ohms" meter is putting out.
(Connect red to red, black to black.)

Test all the "ohms" ranges on the meter, to understand which
ranges are "high power" and "low power". If an ohms range doesn't
put out more than 1 volt open circuit, then it should be relatively
safe to use on just about anything. For the highest resistance
ranges, the results need some interpretation (since the voltmeter
has a finite input impedance of its own)

The $100 The $20
meter meter

Range Ohmmeter Voltmeter Assumed Confidence
Reads Reads Power type

Beep Infinity 2.66V High
Diode infinity 2.67V High High on purpose, for diode
test
200 Infinity 1.01V Low
2K infinity 1.01V Low
20K Infinity 0.48V Low
200K infinity 0.43V Low
2M "0.995" 0.23V Low OK, see interpretation
20M "0.99" 0.04V Low
2000M "001" 0.27V ??? suspicious

(Note - a separate set of tests were done, and the "ohms" multimeter
never applied more than 1 milliamp of current to the test leads. Typical
silicon clamp diodes are rated for about 10 milliamps. So there is
no danger from the level of current flow either.)

In the 2 megohm test case, the "volts" multimeter appears to
have only a 1 megohm input impedance. Half of the open circuit
voltage is across the "volts" multimeter, and half is across
the constant current source inside the meter. We could conclude
from that, that the actual open circuit voltage applied
by the multimeter, is 2 * 0.23 volts or 0.46V. And that is suitable
for low power ohms. So you actually have to stare at the display
on both devices to understand what is going on.

My suspicion is, the "insulation test" range on my multimeter, is
actually high power ohms. It is pretty hard to test insulation,
with a low voltage. Insulation testing would normally be done
with a "megger". Since I am suspicious of what I see for the
2000M range, I likely would not switch to it while working on
the average PCB.

There are quality voltmeters, with much higher input impedance
than my $20 "volts" multimeter used in this test. For such a
device (perhaps a $1000 unit), I likely would not need interpretation
except for the last test case. And the voltmeter in that case, could
tell me what the open circuit voltage is, correctly, for the
rest of the ranges.

The $20 meter is the one I lend to friends :-)

So there are six ranges on my $100 multimeter, that I'd use on a DIMM.
Without being concerned about any side effects to the silicon.

Some older meters, like my analog Simpson, are a bit meaner.
They apply nine volts open circuit, and would be unsuited
for this purpose. I could have run the same set of tests for
my Simpson, but there is no point, because I simply wouldn't
use it. My Simpson is good for volts "trend analysis", as digital
meters aren't perfect for all purposes. There are still
occasions for reaching for my oldest multimeter. "Ohms" would
not be one of those reasons.

If a person had concerns about any silicon device they were
working on, they could look in the datasheet for inspiration.
I haven't done that in this case for the memory chip. I'm reasonably
confident, that the six tested ranges on my multimeter, would
be safe enough.

HTH,
Paul

Regardless of the characteristics of any multimeter, it is a totally
unsuitable device for checking out a RAM chip.

Pegasus [MVP] wrote:


"Paul" schrieb im Newsbeitrag
...
Pegasus [MVP] wrote:


The multimeter test might destroy the RAM chip, like the tap on the
head with the hammer. I find it difficult to think of a more
inappropriate test for a RAM chip. Remember - it contains a hundred
million or more transistor gates operating at extremely low currents,
less than the most sensitive multimeter can detect!

You can safely test silicon devices, if you use a multimeter with
"low power ohms" setting. It applies a voltage not intended to
cause forward conduction in the silicon chips.

If you lost the manual for your multimeter, you can verify this by using
two multimeters. One multimeter set to "ohms". The second multimeter
set to "volts". The "volts" multimeter will show you a rough idea
of the open circuit voltage that the "ohms" meter is putting out.
(Connect red to red, black to black.)

Test all the "ohms" ranges on the meter, to understand which
ranges are "high power" and "low power". If an ohms range doesn't
put out more than 1 volt open circuit, then it should be relatively
safe to use on just about anything. For the highest resistance
ranges, the results need some interpretation (since the voltmeter
has a finite input impedance of its own)

The $100 The $20
meter meter

Range Ohmmeter Voltmeter Assumed Confidence
Reads Reads Power type

Beep Infinity 2.66V High
Diode infinity 2.67V High High on purpose, for
diode test
200 Infinity 1.01V Low
2K infinity 1.01V Low
20K Infinity 0.48V Low
200K infinity 0.43V Low
2M "0.995" 0.23V Low OK, see interpretation
20M "0.99" 0.04V Low
2000M "001" 0.27V ??? suspicious

(Note - a separate set of tests were done, and the "ohms" multimeter
never applied more than 1 milliamp of current to the test leads. Typical
silicon clamp diodes are rated for about 10 milliamps. So there is
no danger from the level of current flow either.)

In the 2 megohm test case, the "volts" multimeter appears to
have only a 1 megohm input impedance. Half of the open circuit
voltage is across the "volts" multimeter, and half is across
the constant current source inside the meter. We could conclude
from that, that the actual open circuit voltage applied
by the multimeter, is 2 * 0.23 volts or 0.46V. And that is suitable
for low power ohms. So you actually have to stare at the display
on both devices to understand what is going on.

My suspicion is, the "insulation test" range on my multimeter, is
actually high power ohms. It is pretty hard to test insulation,
with a low voltage. Insulation testing would normally be done
with a "megger". Since I am suspicious of what I see for the
2000M range, I likely would not switch to it while working on
the average PCB.

There are quality voltmeters, with much higher input impedance
than my $20 "volts" multimeter used in this test. For such a
device (perhaps a $1000 unit), I likely would not need interpretation
except for the last test case. And the voltmeter in that case, could
tell me what the open circuit voltage is, correctly, for the
rest of the ranges.

The $20 meter is the one I lend to friends :-)

So there are six ranges on my $100 multimeter, that I'd use on a DIMM.
Without being concerned about any side effects to the silicon.

Some older meters, like my analog Simpson, are a bit meaner.
They apply nine volts open circuit, and would be unsuited
for this purpose. I could have run the same set of tests for
my Simpson, but there is no point, because I simply wouldn't
use it. My Simpson is good for volts "trend analysis", as digital
meters aren't perfect for all purposes. There are still
occasions for reaching for my oldest multimeter. "Ohms" would
not be one of those reasons.

If a person had concerns about any silicon device they were
working on, they could look in the datasheet for inspiration.
I haven't done that in this case for the memory chip. I'm reasonably
confident, that the six tested ranges on my multimeter, would
be safe enough.

HTH,
Paul

Regardless of the characteristics of any multimeter, it is a totally
unsuitable device for checking out a RAM chip.

Doing an ohms test on the chip itself has no meaning. (Like measuring
the resistance from DQ0 to DQ7. That wouldn't mean anything in particular.)

If you're checking continuity on a series damping resistor,
that could be used as a check that the wiring is OK. For
example, doing this, shows the resistor pack is soldered
down OK.

contact ---- resistor ----- Memory_chip
^ ^
| |
+- ohm from here to here -+

There aren't a lot of other tests you can do.

If you buy "generic" DIMMs by the barrel full, one good test
to run, is measure the rail to rail resistance. Some failed
cheap bypass caps are a dead short, and can cause the motherboard
socket to get burned. (I've seen reports of this on Newegg.)
If you were doing incoming inspection, a quick check between
rails might be a good test. (We actually used to do that
for large circuit packs as well, as an optional test before
applying power. I was surprised, while recording the results
for this test, how well correlated it was. There was little
unit to unit variation, in the ones I recorded. If something
was out of the ordinary, I wouldn't plug in the unit, until
determining why.)

But I can't see a lot of reasons to be using a multimeter
on a DIMM. If memtest shows it is bad, just throw it away
(or return it under the warranty terms). I can't remember
the last time I combined "multimeter" with "DIMM". It would
not be high on my to-do list, if I was just trying to get
something running again.

If you want to play around, as long as the meter uses
low power ohms ranges, I don't see the harm in it. But
you could just as easily spend your time probing a
rock with the multimeter.

Paul

"Paul" screv in ...
But you could just as easily spend your time probing a rock with the
multimeter.

Paul

Exactly. We finally appear to agree.

"Paul" wrote in message ...

If you want to play around, as long as the meter uses
low power ohms ranges, I don't see the harm in it. But
you could just as easily spend your time probing a
rock with the multimeter.

Mine is a small digital multimeter. I think it sends out 1.5 to 2 volts
or so. I don't think that would damage digital equipment would it? That's
about the voltage in my DDRAM that is a "bit turned on".

Bill

Paul wrote:
Pegasus [MVP] wrote:


The multimeter test might destroy the RAM chip, like the tap on the head
with the hammer. I find it difficult to think of a more inappropriate
test for a RAM chip. Remember - it contains a hundred million or more
transistor gates operating at extremely low currents, less than the most
sensitive multimeter can detect!

You can safely test silicon devices, if you use a multimeter with
"low power ohms" setting. It applies a voltage not intended to
cause forward conduction in the silicon chips.

Paul, this only applies to checking *discrete* devices, like diodes and
transistors, it does not apply to integrated circuits.

Pegasus [MVP] wrote:
"Paul" schrieb im Newsbeitrag
...
Pegasus [MVP] wrote:


The multimeter test might destroy the RAM chip, like the tap on the head
with the hammer. I find it difficult to think of a more inappropriate
test for a RAM chip. Remember - it contains a hundred million or more
transistor gates operating at extremely low currents, less than the most
sensitive multimeter can detect!

You can safely test silicon devices, if you use a multimeter with
"low power ohms" setting. It applies a voltage not intended to
cause forward conduction in the silicon chips.

If you lost the manual for your multimeter, you can verify this by using
two multimeters. One multimeter set to "ohms". The second multimeter
set to "volts". The "volts" multimeter will show you a rough idea
of the open circuit voltage that the "ohms" meter is putting out.
(Connect red to red, black to black.)

Test all the "ohms" ranges on the meter, to understand which
ranges are "high power" and "low power". If an ohms range doesn't
put out more than 1 volt open circuit, then it should be relatively
safe to use on just about anything. For the highest resistance
ranges, the results need some interpretation (since the voltmeter
has a finite input impedance of its own)

The $100 The $20
meter meter

Range Ohmmeter Voltmeter Assumed Confidence
Reads Reads Power type

Beep Infinity 2.66V High
Diode infinity 2.67V High High on purpose, for diode
test
200 Infinity 1.01V Low
2K infinity 1.01V Low
20K Infinity 0.48V Low
200K infinity 0.43V Low
2M "0.995" 0.23V Low OK, see interpretation
20M "0.99" 0.04V Low
2000M "001" 0.27V ??? suspicious

(Note - a separate set of tests were done, and the "ohms" multimeter
never applied more than 1 milliamp of current to the test leads. Typical
silicon clamp diodes are rated for about 10 milliamps. So there is
no danger from the level of current flow either.)

In the 2 megohm test case, the "volts" multimeter appears to
have only a 1 megohm input impedance. Half of the open circuit
voltage is across the "volts" multimeter, and half is across
the constant current source inside the meter. We could conclude
from that, that the actual open circuit voltage applied
by the multimeter, is 2 * 0.23 volts or 0.46V. And that is suitable
for low power ohms. So you actually have to stare at the display
on both devices to understand what is going on.

My suspicion is, the "insulation test" range on my multimeter, is
actually high power ohms. It is pretty hard to test insulation,
with a low voltage. Insulation testing would normally be done
with a "megger". Since I am suspicious of what I see for the
2000M range, I likely would not switch to it while working on
the average PCB.

There are quality voltmeters, with much higher input impedance
than my $20 "volts" multimeter used in this test. For such a
device (perhaps a $1000 unit), I likely would not need interpretation
except for the last test case. And the voltmeter in that case, could
tell me what the open circuit voltage is, correctly, for the
rest of the ranges.

The $20 meter is the one I lend to friends :-)

So there are six ranges on my $100 multimeter, that I'd use on a DIMM.
Without being concerned about any side effects to the silicon.

Some older meters, like my analog Simpson, are a bit meaner.
They apply nine volts open circuit, and would be unsuited
for this purpose. I could have run the same set of tests for
my Simpson, but there is no point, because I simply wouldn't
use it. My Simpson is good for volts "trend analysis", as digital
meters aren't perfect for all purposes. There are still
occasions for reaching for my oldest multimeter. "Ohms" would
not be one of those reasons.

If a person had concerns about any silicon device they were
working on, they could look in the datasheet for inspiration.
I haven't done that in this case for the memory chip. I'm reasonably
confident, that the six tested ranges on my multimeter, would
be safe enough.

HTH,
Paul

Regardless of the characteristics of any multimeter, it is a totally
unsuitable device for checking out a RAM chip.

That is correct.

Paul wrote:
Pegasus [MVP] wrote:


"Paul" schrieb im Newsbeitrag
...
Pegasus [MVP] wrote:


The multimeter test might destroy the RAM chip, like the tap on the
head with the hammer. I find it difficult to think of a more
inappropriate test for a RAM chip. Remember - it contains a hundred
million or more transistor gates operating at extremely low currents,
less than the most sensitive multimeter can detect!

You can safely test silicon devices, if you use a multimeter with
"low power ohms" setting. It applies a voltage not intended to
cause forward conduction in the silicon chips.

If you lost the manual for your multimeter, you can verify this by using
two multimeters. One multimeter set to "ohms". The second multimeter
set to "volts". The "volts" multimeter will show you a rough idea
of the open circuit voltage that the "ohms" meter is putting out.
(Connect red to red, black to black.)

Test all the "ohms" ranges on the meter, to understand which
ranges are "high power" and "low power". If an ohms range doesn't
put out more than 1 volt open circuit, then it should be relatively
safe to use on just about anything. For the highest resistance
ranges, the results need some interpretation (since the voltmeter
has a finite input impedance of its own)

The $100 The $20
meter meter

Range Ohmmeter Voltmeter Assumed Confidence
Reads Reads Power type

Beep Infinity 2.66V High
Diode infinity 2.67V High High on purpose, for
diode test
200 Infinity 1.01V Low
2K infinity 1.01V Low
20K Infinity 0.48V Low
200K infinity 0.43V Low
2M "0.995" 0.23V Low OK, see interpretation
20M "0.99" 0.04V Low
2000M "001" 0.27V ??? suspicious

(Note - a separate set of tests were done, and the "ohms" multimeter
never applied more than 1 milliamp of current to the test leads. Typical
silicon clamp diodes are rated for about 10 milliamps. So there is
no danger from the level of current flow either.)

In the 2 megohm test case, the "volts" multimeter appears to
have only a 1 megohm input impedance. Half of the open circuit
voltage is across the "volts" multimeter, and half is across
the constant current source inside the meter. We could conclude
from that, that the actual open circuit voltage applied
by the multimeter, is 2 * 0.23 volts or 0.46V. And that is suitable
for low power ohms. So you actually have to stare at the display
on both devices to understand what is going on.

My suspicion is, the "insulation test" range on my multimeter, is
actually high power ohms. It is pretty hard to test insulation,
with a low voltage. Insulation testing would normally be done
with a "megger". Since I am suspicious of what I see for the
2000M range, I likely would not switch to it while working on
the average PCB.

There are quality voltmeters, with much higher input impedance
than my $20 "volts" multimeter used in this test. For such a
device (perhaps a $1000 unit), I likely would not need interpretation
except for the last test case. And the voltmeter in that case, could
tell me what the open circuit voltage is, correctly, for the
rest of the ranges.

The $20 meter is the one I lend to friends :-)

So there are six ranges on my $100 multimeter, that I'd use on a DIMM.
Without being concerned about any side effects to the silicon.

Some older meters, like my analog Simpson, are a bit meaner.
They apply nine volts open circuit, and would be unsuited
for this purpose. I could have run the same set of tests for
my Simpson, but there is no point, because I simply wouldn't
use it. My Simpson is good for volts "trend analysis", as digital
meters aren't perfect for all purposes. There are still
occasions for reaching for my oldest multimeter. "Ohms" would
not be one of those reasons.

If a person had concerns about any silicon device they were
working on, they could look in the datasheet for inspiration.
I haven't done that in this case for the memory chip. I'm reasonably
confident, that the six tested ranges on my multimeter, would
be safe enough.

HTH,
Paul

Regardless of the characteristics of any multimeter, it is a totally
unsuitable device for checking out a RAM chip.

Doing an ohms test on the chip itself has no meaning. (Like measuring
the resistance from DQ0 to DQ7. That wouldn't mean anything in
particular.)

Exactly. It can be fairly useful for some discrete devices like diodes
and transistors, however, but is completely inadequate for integrated
circuits.

If you're checking continuity on a series damping resistor,
that could be used as a check that the wiring is OK. For
example, doing this, shows the resistor pack is soldered
down OK.

contact ---- resistor ----- Memory_chip
^ ^
| |
+- ohm from here to here -+

There aren't a lot of other tests you can do.

And that's a pretty limited test.

If you buy "generic" DIMMs by the barrel full, one good test
to run, is measure the rail to rail resistance. Some failed
cheap bypass caps are a dead short, and can cause the motherboard
socket to get burned. (I've seen reports of this on Newegg.)

Again, that is a pretty limited test. Extremely limited!!

If you were doing incoming inspection, a quick check between
rails might be a good test. (We actually used to do that
for large circuit packs as well, as an optional test before
applying power. I was surprised, while recording the results
for this test, how well correlated it was. There was little
unit to unit variation, in the ones I recorded. If something
was out of the ordinary, I wouldn't plug in the unit, until
determining why.)

But I can't see a lot of reasons to be using a multimeter
on a DIMM.

Because there really aren't any, for all practical purposes. Simply
checking whether or not a capacitor on the board is shorted is a very
limited test of the IC (actually, it's not even testing the IC itself).

"Bill in Co." wrote in message
...

Paul, this only applies to checking *discrete* devices, like diodes and
transistors, it does not apply to integrated circuits.

So I couldn't use a multimeter to check my machine's transformer that
steps down 120 V powersupply or the system buses in the motherboard?

Bill

Bill Cunningham wrote:
"Bill in Co." wrote in message
...

Paul, this only applies to checking *discrete* devices, like diodes and
transistors, it does not apply to integrated circuits.

So I couldn't use a multimeter to check my machine's transformer that
steps down 120 V powersupply or the system buses in the motherboard?

Bill

Of course you could. We were talking about semiconductor devices (like ICs
= integrated circuits) in this discussion, not transformers, resistors, etc.
But just FYI, a transformer is also a discrete (i.e. not integrated) device.
:-)

"Bill in Co." wrote in message
...

Of course you could. We were talking about semiconductor devices (like
ICs = integrated circuits) in this discussion, not transformers,
resistors, etc. But just FYI, a transformer is also a discrete (i.e. not
integrated) device. :-)

Isn't the motherboard, system bus, address bus and so on made of ICs?
Can a person test memory with a multimeter via the motherboard and its
bridges?

Bill

Bill Cunningham wrote:
"Bill in Co." wrote in message
...

Of course you could. We were talking about semiconductor devices (like
ICs = integrated circuits) in this discussion, not transformers,
resistors, etc. But just FYI, a transformer is also a discrete (i.e. not
integrated) device. :-)

Isn't the motherboard, system bus, address bus and so on made of ICs?

AND some discrete components.

Can a person test memory with a multimeter via the motherboard and its
bridges?

No.