Is there a way to test an IC voltage regulator with a digital volt
meter? I have a three pin adjustable voltage regulator and I need to
know if it is bad.

Thanks!

Milkman

On May 12, 9:23 pm, LVMilkman wrote:
Is there a way to test an IC voltage regulator with a digital volt
meter? I have a three pin adjustable voltage regulator and I need
to
know if it is bad.

Thanks!

Milkman

If there are no shorts between pins (totally trashed), the usual
method is to connect it up with the proper resistors and measure the
actual output under varying loads. Is there any other way?

GG

wrote in message
oups.com...
On May 12, 9:23 pm, LVMilkman wrote:
Is there a way to test an IC voltage regulator with a digital volt
meter? I have a three pin adjustable voltage regulator and I need
to
know if it is bad.

Thanks!

Milkman

If there are no shorts between pins (totally trashed), the usual
method is to connect it up with the proper resistors and measure the
actual output under varying loads. Is there any other way?

GG

Not that I know of, and that is certainly the way that I do it. They are
pretty reliable though, if we're talking something like an LM317T. I repair
about 6 or 7 hundred per year of a particular board that uses one. I would
guess that I get perhaps 10 regulator problems in that number, and amongst
those, probably only 3 or 4 are the device itself. The rest are o/c
resistors in the output voltage set chain, or short circuit caps at the set
or output pins.

Arfa

Meat Plow wrote:

On Sun, 13 May 2007 11:30:45 +0000, Arfa Daily wrote:

Not that I know of, and that is certainly the way that I do it. They are
pretty reliable though, if we're talking something like an LM317T. I repair
about 6 or 7 hundred per year of a particular board that uses one

LOL pretty reliable and you repair that many?


I repaired over 10,000 CATV converters for United Video's Cincinnati,
Ohio system in the early '80s, along with commercial C-band microwave
receivers and other headend equipment for over a dozen CATV systems in a
four year period. I processed the converters 100 at a time, unless the
total spare stock was below that number and ran a production line
repair, kicking out the few dogs to finish last.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Meat Plow" wrote in message
...
On Sun, 13 May 2007 11:30:45 +0000, Arfa Daily wrote:

Not that I know of, and that is certainly the way that I do it. They are
pretty reliable though, if we're talking something like an LM317T. I
repair
about 6 or 7 hundred per year of a particular board that uses one

LOL pretty reliable and you repair that many?




Hey Meat, how's it going?
Perhaps you misunderstood what I said. I stated that I repaired 6 or 7
hundred a year of a particular board that happens to *use* an LM317T. I then
went on to explain that of those several hundred, *very few* of the faults
that the boards had, were related to that '317.

Actually, I've just looked at the figures, and I do about 100 every 6 weeks,
so it's actually nearer 800 a year. This board has an LM317T and a 7805 on
it, neither of which are heatsunk by anything other than being screwed down
( and often not very well ) to the PCB. Both of these regs run too hot to
touch in normal use. I have a separate spares drawer cabinet for the repair
of these, and in it, I keep a running stock of 5 LM317's, which I replenish
perhaps once a year. The very occasional power supply faults that these
boards suffer on their 12v rail, which the '317 is used to derive from the
raw 24v supply, are almost invariably o/c surface mount R's in the voltage
set network, or s/c tantalum surface mount caps.

Considering that these devices are s/c, thermal, and SOA protected, this
pretty much puts them outside being damaged by external conditions, so any
failures have to be random chance. Semicon manufacturers have got random
chance failures, after the bottom of the bathtub, licked these days, so I
don't see why you find the fact that I don't have very much trouble with the
317's, given the number that pass by me, funny ??

Do you have some other experience of them ? Am I alone in not seeing a big
reliability problem ? Just interested ... d;~}

Arfa

On May 14, 1:37 am, "Arfa Daily" wrote:
"Meat Plow" wrote in message

...

On Sun, 13 May 2007 11:30:45 +0000, Arfa Daily wrote:

Not that I know of, and that is certainly the way that I do it. They are
pretty reliable though, if we're talking something like an LM317T. I
repair
about 6 or 7 hundred per year of a particular board that uses one

LOL pretty reliable and you repair that many?



Hey Meat, how's it going?
Perhaps you misunderstood what I said. I stated that I repaired 6 or 7
hundred a year of a particular board that happens to *use* an LM317T. I then
went on to explain that of those several hundred, *very few* of the faults
that the boards had, were related to that '317.

Actually, I've just looked at the figures, and I do about 100 every 6 weeks,
so it's actually nearer 800 a year. This board has an LM317T and a 7805 on
it, neither of which are heatsunk by anything other than being screwed down
( and often not very well ) to the PCB. Both of these regs run too hot to
touch in normal use. I have a separate spares drawer cabinet for the repair
of these, and in it, I keep a running stock of 5 LM317's, which I replenish
perhaps once a year. The very occasional power supply faults that these
boards suffer on their 12v rail, which the '317 is used to derive from the
raw 24v supply, are almost invariably o/c surface mount R's in the voltage
set network, or s/c tantalum surface mount caps.

Considering that these devices are s/c, thermal, and SOA protected, this
pretty much puts them outside being damaged by external conditions, so any
failures have to be random chance. Semicon manufacturers have got random
chance failures, after the bottom of the bathtub, licked these days, so I
don't see why you find the fact that I don't have very much trouble with the
317's, given the number that pass by me, funny ??

Do you have some other experience of them ? Am I alone in not seeing a big
reliability problem ? Just interested ... d;~}

Arfa


Guys:
Thanks for the help and I really appreciate the advice of the down
stream resisitors. I will check all components, I just was not sure
how to check a voltage regulator, but it seems that there is no easy
way to do that with a DVM.

Thanks again,

Milkman