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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Anyone know a DVM exorcist?
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 |
#2
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Anyone know a DVM exorcist?
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. 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 |
#3
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Anyone know a DVM exorcist?
On Mar 26, 3:15*am, "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 Now THAT's dedication, sleeping with your DVM. |
#4
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Anyone know a DVM exorcist?
William Sommerwerck wrote in message
... 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 never with my Fluke 77 but did have it with a SOAR 3210 DVM with low battery |
#5
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Anyone know a DVM exorcist?
The battery enunciator has been coming on lately...
Sorry. I meant annunciator. Ouch. |
#6
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Anyone know a DVM exorcist?
Now THAT's dedication, sleeping with your DVM.
Uh... It was on the floor. Next to the bed. Really. |
#7
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Anyone know a DVM exorcist?
On Mon, 26 Mar 2012 03:15:20 -0700, "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. 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 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#8
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Anyone know a DVM exorcist?
Jeff Liebermann wrote in
: On Mon, 26 Mar 2012 03:15:20 -0700, "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. 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 |
#9
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Anyone know a DVM exorcist?
On Monday, March 26, 2012 1:25:13 PM UTC-4, Jim Yanik wrote:
Jeff Liebermann wrote in : On Mon, 26 Mar 2012 03:15:20 -0700, "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. 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 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 |
#10
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Anyone know a DVM exorcist?
On Mon, 26 Mar 2012 12:25:13 -0500, Jim Yanik
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/ -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#11
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Anyone know a DVM exorcist?
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. |
#12
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Anyone know a DVM exorcist?
Jeff Liebermann wrote:
On Mon, 26 Mar 2012 03:15:20 -0700, "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. 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." |
#13
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Anyone know a DVM exorcist?
On Mar 26, 6:15*am, "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 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 |
#14
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Anyone know a DVM exorcist?
"Phil Hobbs" wrote in message
... 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. 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 Could it be just the function switch is flaky and needs cleaning? Mark Z. |
#15
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Anyone know a DVM exorcist?
Mark Zacharias wrote:
"Phil Hobbs" wrote in message ... 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. 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 |
#16
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Anyone know a DVM exorcist?
On Mon, 26 Mar 2012 12:08:43 -0700, "William Sommerwerck"
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 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#17
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Anyone know a DVM exorcist?
On Mon, 26 Mar 2012 12:13:29 -0700, John Robertson
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. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#18
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Anyone know a DVM exorcist?
Jeff Liebermann wrote:
On Mon, 26 Mar 2012 12:13:29 -0700, John Robertson 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! 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." |
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