Anyone know a DVM exorcist?

[William Sommerwerck]

I was in bed, watching TV, when I noticed an unfamiliar clicking sound. It
persisted, so I leaned over and saw my Fluke 87's backlight flickering, and
heard it clicking. (The knob was in the off position, by the way.) Turning
it on, then off, ended this weird behavior.

The battery enunciator has been coming on lately, so I have to assume it's a
side-effect of low voltage.

--
"We already know the answers -- we just haven't asked the right
questions." -- Edwin Land

[Phil Hobbs]

I have an old original Fluke 87 that did that. It turned out that the
switch rotor had got chipped, allowing the switch to rotate just a bit
past the "Off" position.

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

[Robert Macy]

On Mar 26, 3:15 am, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:

Now THAT's dedication, sleeping with your DVM. ;)

[N_Cook]

William Sommerwerck <grizzle...@comcast.net> wrote in message
news:jkpfi0$6jf$1...@dont-email.me...

never with my Fluke 77 but did have it with a SOAR 3210 DVM with low battery

[William Sommerwerck]

> The battery enunciator has been coming on lately...

Sorry. I meant annunciator. Ouch.

[William Sommerwerck]

> Now THAT's dedication, sleeping with your DVM. ;)

Uh... It was on the floor. Next to the bed. Really.

[Jeff Liebermann]

On Mon, 26 Mar 2012 03:15:20 -0700, "William Sommerwerck"
<grizzle...@comcast.net> wrote:

>I was in bed, watching TV, when I noticed an unfamiliar clicking sound. It
>persisted, so I leaned over and saw my Fluke 87's backlight flickering, and
>heard it clicking. (The knob was in the off position, by the way.) Turning
>it on, then off, ended this weird behavior.

My Fluke 77 does that when the 9V battery is not quite totally dead.

>The battery enunciator has been coming on lately, so I have to assume it's a
>side-effect of low voltage.

Yep. You'll also find that it gives wrong voltage readings with a low
battery. The irritating part is that it will give bogus readings long
before the battery is obviously dead.



--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Jim Yanik]

Jeff Liebermann <je...@cruzio.com> wrote in
news:ea91n7h0976j5ah8q...@4ax.com:

> On Mon, 26 Mar 2012 03:15:20 -0700, "William Sommerwerck"
><grizzle...@comcast.net> wrote:
>
>>I was in bed, watching TV, when I noticed an unfamiliar clicking
>>sound. It persisted, so I leaned over and saw my Fluke 87's backlight
>>flickering, and heard it clicking. (The knob was in the off position,
>>by the way.) Turning it on, then off, ended this weird behavior.
>
> My Fluke 77 does that when the 9V battery is not quite totally dead.
>
>>The battery enunciator has been coming on lately, so I have to assume
>>it's a side-effect of low voltage.
>
> Yep. You'll also find that it gives wrong voltage readings with a low
> battery. The irritating part is that it will give bogus readings long
> before the battery is obviously dead.
>
>
>

doesn't it have a LOW-BATT indicator on the LCD screen?

--
Jim Yanik
jyanik
at
localnet
dot com

[dansabr...@yahoo.com]

To avoid the incorrect readings, use alkaline batteries. The meter will remian more accurate for longer this way.

Yes, the Fluke 77 has a low pattery indicator. I have found that the unit gets a bit unstable before that indicator comes on. I check the battery regularly to prevent this. I don't rely on the low battery indicator.

Dan

[Jeff Liebermann]

On Mon, 26 Mar 2012 12:25:13 -0500, Jim Yanik <jya...@abuse.gov>
wrote:

>doesn't it have a LOW-BATT indicator on the LCD screen?

Yes. The Fluke 77 has a rectangular battery symbol in the upper left
corner of the screen. When it comes on, the battery is certainly
dead. However, voltage measurements go insane somewhat before the
indicator comes on. I was checking my supply of AA alkalines in the
fridge and noticed that I was tossing far too many batteries as dead.
I checked the readings with another DVM and found that the Fluke 77
was erratically reading about 300mv low. The battery indicator never
came on. When I replaced the battery, the readings returned to
normal. I don't recall if the flashing display happened before or
after the battery indicator.

That was with an alkaline 9V battery. I'm tempted to spend the $7.00
and get a "smoke alarm" lithium battery such as an Ultralife:
<http://ultralifecorporation.com/be-commercial/products/9volt/>

[William Sommerwerck]

>> doesn't it have a LOW-BATT indicator on the LCD screen?

> Yes. The Fluke 77 has a rectangular battery symbol in the upper left
> corner of the screen. When it comes on, the battery is certainly dead.

You mean useless. If it were dead...

> However, voltage measurements go insane somewhat before the
> indicator comes on. I was checking my supply of AA alkalines in the
> fridge and noticed that I was tossing far too many batteries as dead.

This is Most Amusing, because I was checking a pile of NiMH AA cells, and
most of them read a few tenths of a volt. Then, a few hours later, they were
all fine.

In case you're wondering... Of course I use an alkaline battery. A lithium
would be an even better choice. MCM has name-brand lithium 9V batteries for
about $5 right now.

[John Robertson]

Jeff Liebermann wrote:
> On Mon, 26 Mar 2012 03:15:20 -0700, "William Sommerwerck"
> <grizzle...@comcast.net> wrote:
>
>> I was in bed, watching TV, when I noticed an unfamiliar clicking sound. It
>> persisted, so I leaned over and saw my Fluke 87's backlight flickering, and
>> heard it clicking. (The knob was in the off position, by the way.) Turning
>> it on, then off, ended this weird behavior.
>
> My Fluke 77 does that when the 9V battery is not quite totally dead.
>
>> The battery enunciator has been coming on lately, so I have to assume it's a
>> side-effect of low voltage.
>
> Yep. You'll also find that it gives wrong voltage readings with a low
> battery. The irritating part is that it will give bogus readings long
> before the battery is obviously dead.
>
>
>

Can you calibrate the Battery Low feature? One would think so...

John :-#)#
--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

[John-Del]

On Mar 26, 6:15 am, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:

FWIW, I had two 87s (early type) die slowly, and in the same manner.
It started out with the beeper making various noises for no reason.
In both units, I opened up the case and disabled the sounder with some
cellophane tape between the sounder and the main board. Later, they
became flakey and eventually stopped completely. My 77, which has
outlasted two 87s, is bulletproof, but doesn't have the features,
speed, resolution, or immunity to noisy situations, like reading dc
voltages in flyback\smps circuits that the 87s have.

John

[Mark Zacharias]

"Phil Hobbs" <pcdhSpamM...@electrooptical.net> wrote in message
news:4F70640E...@electrooptical.net...

Could it be just the function switch is flaky and needs cleaning?

Mark Z.

[Phil Hobbs]

Mark Zacharias wrote:
>
> "Phil Hobbs" <pcdhSpamM...@electrooptical.net> wrote in message
> news:4F70640E...@electrooptical.net...
> > William Sommerwerck wrote:
> >>
> >> I was in bed, watching TV, when I noticed an unfamiliar clicking sound.
> >> It
> >> persisted, so I leaned over and saw my Fluke 87's backlight flickering,
> >> and
> >> heard it clicking. (The knob was in the off position, by the way.)
> >> Turning
> >> it on, then off, ended this weird behavior.
> >>
> >> The battery enunciator has been coming on lately, so I have to assume
> >> it's a
> >> side-effect of low voltage.
> >>
> >> --
> >> "We already know the answers -- we just haven't asked the right
> >> questions." -- Edwin Land
> >
> >
> > I have an old original Fluke 87 that did that. It turned out that the
> > switch rotor had got chipped, allowing the switch to rotate just a bit
> > past the "Off" position.

>

> Could it be just the function switch is flaky and needs cleaning?
>
> Mark Z.

Don't think so. You can see where the missing chunk allowed the rotor
to go about 60 or 80 mils past the "off" position, and preventing this
fixed the problem.

[Jeff Liebermann]

On Mon, 26 Mar 2012 12:08:43 -0700, "William Sommerwerck"
<grizzle...@comcast.net> wrote:

>>> doesn't it have a LOW-BATT indicator on the LCD screen?
>
>> Yes. The Fluke 77 has a rectangular battery symbol in the upper left
>> corner of the screen. When it comes on, the battery is certainly dead.
>
>You mean useless. If it were dead...

It's a common design problem. How does one provide an active
indication that the power source is dead, when the indicator is
powered by the same power source. The usual "solution" is to have the
indicator proclaim a dead battery, long before the device ceases to
function. My HP calculators mostly do it that way. I can run them
for months with the dead battery indicator showing.

>> However, voltage measurements go insane somewhat before the
>> indicator comes on. I was checking my supply of AA alkalines in the
>> fridge and noticed that I was tossing far too many batteries as dead.
>
>This is Most Amusing, because I was checking a pile of NiMH AA cells, and
>most of them read a few tenths of a volt. Then, a few hours later, they were
>all fine.

Ummm... I don't think that's the result of a low battery in your Fluke
78. My 77 is similar and simply produces modest errors before it
quits completely. A few tenths of a volt is a rather drastic error.
Check the probes?

>In case you're wondering... Of course I use an alkaline battery. A lithium
>would be an even better choice. MCM has name-brand lithium 9V batteries for
>about $5 right now.

Cool. I need some other parts from MCM. Thanks.

[Jeff Liebermann]

On Mon, 26 Mar 2012 12:13:29 -0700, John Robertson <sp...@flippers.com>
wrote:

>Can you calibrate the Battery Low feature? One would think so...
>John :-#)#

Calibrate? Methinks not. There no adjustments.

I got lazy and tried to measure the battery voltage using the
voltmeter. I suppose I could install a switch to do that
automatically and call it a "battery test" function.

I have an analog battery tester that puts a small load on the battery
when measuring. It works much better than any open circuit
measurement. However, I can never seem to find it when I need it.

[John Robertson]

Jeff Liebermann wrote:
> On Mon, 26 Mar 2012 12:13:29 -0700, John Robertson <sp...@flippers.com>
> wrote:
>
>> Can you calibrate the Battery Low feature? One would think so...
>> John :-#)#
>
> Calibrate? Methinks not. There no adjustments.
>
> I got lazy and tried to measure the battery voltage using the
> voltmeter. I suppose I could install a switch to do that
> automatically and call it a "battery test" function.
>
> I have an analog battery tester that puts a small load on the battery
> when measuring. It works much better than any open circuit
> measurement. However, I can never seem to find it when I need it.
>

What about adding a terminal or test point somewhere on the case that
connects to the positive terminal on your battery? On my cheap (but
remarkedly durable after ten years of being dropped) meter the readings
I get on the battery positive terminal are 3.06 (using the red + probe)
and -6.03 (with the black - probe) this shows a battery of 9.09VDC charge.

My meter did not like my using the negative probe on the negative
terminal of the battery - it buzzed at me!