multimeter

[dilbert firestorm]

can anyone recommend a good multimeter for checking voltage on mobos & psu?

I would like to get one for me......

I recieved a faulty diagonsis from a repair shop who said my pc had a bad
mobo. (no socket 370 to test with). so I took it to another shop that had
socket 370 to have the cpu tested. they tell me its bad psu......

sigh....

 

[w_tom]

Just about any $20 multimeter (at least 3.5 digits) sold in
Home Depot, Radio Shack, Sears, or Lowes canl perform a PSU
'system' verification.

 

[Looker007]

can anyone recommend a good multimeter for checking voltage on mobos & psu?

I would like to get one for me......

I recieved a faulty diagonsis from a repair shop who said my pc had a
bad mobo. (no socket 370 to test with). so I took it to another shop
that had socket 370 to have the cpu tested. they tell me its bad
psu......

sigh....

Fluke

 

[Guest]

can anyone recommend a good multimeter for checking voltage
on mobos & psu?

I recieved a faulty diagonsis from a repair shop who said
my pc had a bad mobo. (no socket 370 to test with). so I
took it to another shop that had socket 370 to have the cpu
tested. they tell me its bad psu......

Did the first shop charge you anything? Did they test your power
supply?

Did the second shop test your power supply?

Fluke meters are the best, but you don't need anything nearly that
expensive, and generally any $5-20 meter capable of displaying at least
a 2000 count (displays from 0000-1999, also called "3.5 digit") is more
than adequate. Sears, Wal-Mart, Fry's, Radio Shack have decent
selections, but to get an idea of every meter available, look in the
catalogs of www.mcminone.com , www.contacteast.com , and www.extech.com
.. More elaborate meters can also measure temperature, frequency, RPM,
or capacity, memorize readings, or even send a data stream to a
computer (usually through an old RS-232 serial port, not USB).

 

[dilbert firestorm]

Did the first shop charge you anything? Did they test your power
supply?

yes. they claimed they did. I think there was a possiblity that they were
using a cheap PSU with a low 12volt amp. I had an antec psu that died last
year (it lasted 3 years) and they put in a cheap 420v psu with a low
12volt amp. this lasted 1 year.

Did the second shop test your power supply?

yes, they did. the guy at the shop got it to post on a new psu. don't know
if this is a good psu with high 12 volt amp. it sounds like it might be.

I have 6 scsi hard drives, scsi tape drive, & scsi cd rom. I will be
adding a ide dvd writer to the mix.

Fluke meters are the best, but you don't need anything nearly that
expensive, and generally any $5-20 meter capable of displaying at least
a 2000 count (displays from 0000-1999, also called "3.5 digit") is more
than adequate. Sears, Wal-Mart, Fry's, Radio Shack have decent
selections, but to get an idea of every meter available, look in the
catalogs of www.mcminone.com , www.contacteast.com , and www.extech.com
. More elaborate meters can also measure temperature, frequency, RPM,
or capacity, memorize readings, or even send a data stream to a
computer (usually through an old RS-232 serial port, not USB).

thanx, I will check them out.

 

[johns]

I have 6 scsi hard drives, scsi tape drive, & scsi cd rom. I will be
adding a ide dvd writer to the mix.

All powered by the same supply ? You are frying your psu
doing that. Why so much old junk? scsi tape ... cd ??
Time to start over from scratch ... 1 SATA drive .. 1 Sony
cdrwdvd .. 1 USB drive, and you are done, and you have
10 times the machine that you have now.

johns

 

[dilbert firestorm]

All powered by the same supply ? You are frying your psu
doing that. Why so much old junk? scsi tape ... cd ??
Time to start over from scratch ... 1 SATA drive .. 1 Sony
cdrwdvd .. 1 USB drive, and you are done, and you have
10 times the machine that you have now.

johns

I'm a pack rat, I hate to throw out good junk. besides, I hate to waste
good drive space.

i guess I prolly can retire the 2 gig python scsi tape drive tho, its just
too hard to back up 52 megs of drives (4 lvd, 2 scsi-2).

its good for backing up the os tho.

 

[w_tom]

Just because something is replaced and appears to work
instead can even mean a symptom was cured. A marginal power
supply controller could have made one supply look bad and
another look good. Just another reason why one first uses the
meter before replacing something. If the power supply was
really defective, then the meter would have made it obvious
what had failed. Problems that still exist elsewhere could be
the original reason for earlier supply failures.

BTW, two power supplies in so many years? Statistically it
is not power supplies that are reason for failure.

If the power supply has insufficient 12 volt output, then is
the power supply damaged? No. Obviously no. No, even 30
years ago no. No as in don't even ask to go to Cabo. Either
the power supply outputs everything necessary, or the power
supply simply shuts down all voltages - without damage. Short
together all outputs from a power supply and apply power.
Will the power supply be damaged? Yes, if defective when
purchased. But all power supply outputs must be shorted - and
still the power supply cannot be damaged. So why did you have
power supply failures? Overloading the 12 volts? Not possible
if the power supply was acceptable when purchased. Time to
suspect something else.

Just saying a supply is defective is not sufficient. Why
is it defective? A good shop could have written that on the
invoice. Power supply defective often means they just swapped
parts until something worked - leaving a potential defect
unidentified. Just another reason why numbers from the meter
would provide useful information.

 

[dilbert firestorm]

got my computer today, they told they rechecked the computer, besides the
psu being bad, the mobo was also bad. the cpu however is still good.

with regard to overloading, can the mobo affect the psu?

 

[w_tom]

Defective power supply must include circuits that make it
impossible to harm the motherboard and other components. That
assumes the power supply includes basic functions required
specifically by Intel specs. And a failed motherboard cannot
damage a power supply. As also specifically stated in Intel
specs AND demonstrated by:
If they declare a component defective, then the immediate
question is "Why?" Why do they know it is defective? What
specifically says it is defective? That is what the
multimeter reports. Ask the question and he could provide the
number. Either power supply is obviously defective and a
specific number on that meter says so, or there is nothing
wrong with that power supply.

Common for computer assemblers to just keep replacing parts
until something works. It's called shotgunning. A technique
used because so many computer assemblers don't understand
basic electrical principles. For example, does the computer
assembler know why a power supply must not damage? Does the
assembler even know that all power supply outputs must be
shorted without damage - even a motherboard cannot damage the
power supply? Overloading a power supply must not cause
computer damage. Two simple questions to separate the
shotgunner from one who is electrically literate. Shotgunning
is so common even with certified computer techs who need not
know any of this to pass those tests.