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.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #11   Report Post  
Old February 4th 08, 06:43 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,572
Default Fluke 79 acting up



You should check its battery, that's where your problem is. Electronic
meters utilize A/D converter, the converter uses Voltage reference, when
battery is weak it give faulty voltage reference, as a result you get
faulty reading. Do not rely on voltage reading, sufficient voltages do
not
mean sufficient Battery without enough current in battery.


I put a brand new battery in it, the symptoms are unchanged.



  #12   Report Post  
Old February 4th 08, 07:37 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,572
Default Fluke 79 acting up


"Meat Plow" wrote in message
...
On Mon, 04 Feb 2008 04:10:23 +0000, James Sweet wrote:



I invested in a moulded rubber surround for my 77, after repairing one
that had been jarred and the main SMD chip had loosened. Someone I know
managed to put his knee on his, while working on the floor, and also
dislodge the main chip. Both repaired after attending to the main chip.



I have the rubber surround, and it hasn't been jarred, it was sitting in
the
closet where I always keep it.

I ordered a Fluke 187, I've wanted true RMS for a while anyway. When that
gets here I'll use it to try to fix the 77 and use that as a backup.


Do you have a 77 or was the 79 a typo?


The 79 was a typo, I have a 77, and I ordered an 87, I'm full of typos
lately. I really liked the 77, aside from its lack of true RMS, it did
everything I ever asked it to, I hope the 87 lives up to what I've come to
expect.


  #13   Report Post  
Old February 4th 08, 10:01 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Aug 2006
Posts: 519
Default Fluke 79 acting up

James Sweet wrote:
This thing has performed flawlessly for many years, but when I turned it on
today something was not right. The ohms range flickers random readings, with
no probes plugged in I get around 230K on the display, or 2.22M, depending
on the range, which would imply that the problem is ahead of the scaling
circuit. When I switch to the low ohms range, the reading starts around 240
ohms and then drops to -0.00 over a period of 10 seconds or so, frequency
reading works, but AC volts reads 70mV when plugged into a 120V outlet.
Something strange is going on! I realized that I don't currently have a
backup meter, I suppose I could use this as an excuse to buy a true RMS
Fluke, I don't think I can bring myself to buy a cheapie, except perhaps as
a backup. Anyone run into this?


Is the fuse intact?

--
God help us all,
The next President of the United States will be a liberal.
  #14   Report Post  
Old February 4th 08, 10:07 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,572
Default Fluke 79 acting up


"clifto" wrote in message
...
James Sweet wrote:
This thing has performed flawlessly for many years, but when I turned it
on
today something was not right. The ohms range flickers random readings,
with
no probes plugged in I get around 230K on the display, or 2.22M,
depending
on the range, which would imply that the problem is ahead of the scaling
circuit. When I switch to the low ohms range, the reading starts around
240
ohms and then drops to -0.00 over a period of 10 seconds or so, frequency
reading works, but AC volts reads 70mV when plugged into a 120V outlet.
Something strange is going on! I realized that I don't currently have a
backup meter, I suppose I could use this as an excuse to buy a true RMS
Fluke, I don't think I can bring myself to buy a cheapie, except perhaps
as
a backup. Anyone run into this?


Is the fuse intact?


I assume so, I didn't do anything that would blow it, but other times the
fuse has blown it has not exhibited any unusual behavior. I know what I'm
doing, I tried all the simple stuff, something has failed.


  #15   Report Post  
Old February 4th 08, 10:09 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,572
Default Fluke 79 acting up



I have an old 77. Serial number 4333xxxxxx. Still works like a charm.
Zeros out on any setting. Wouldn't mind having an 87 and keeping the 77
for a backup. Where did you find the best price?


Ebay, they tend to go for about $160 used and in good shape, closer to $300
new. There's several different models of 87, make sure you know which one
you're getting.




  #16   Report Post  
Old February 4th 08, 10:47 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Feb 2008
Posts: 44
Default Fluke 79 acting up


"William Sommerwerck" wrote in message
...
"Jakthehammer" wrote in message
...

You should check its battery, that's where your problem is.
Electronic meters utilize A/D converter. The A/D converter
uses bat as Voltage reference...


Actually, a semiconductor device similar to a Zener diode is used as the
voltage reference. But the battery has to be at or above the device's
threshold to provide a stable reference.



Correctly, the zener (or an IC reference circuit) are part of the A/D
circuit. You cannot design a complete A/D without Voltage Referencing.

Jack....

  #17   Report Post  
Old February 4th 08, 11:10 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,220
Default Fluke 77 acting up

James Sweet wrote in message
news:[email protected]

"clifto" wrote in message
...
James Sweet wrote:
This thing has performed flawlessly for many years, but when I turned

it
on
today something was not right. The ohms range flickers random readings,
with
no probes plugged in I get around 230K on the display, or 2.22M,
depending
on the range, which would imply that the problem is ahead of the

scaling
circuit. When I switch to the low ohms range, the reading starts around
240
ohms and then drops to -0.00 over a period of 10 seconds or so,

frequency
reading works, but AC volts reads 70mV when plugged into a 120V outlet.
Something strange is going on! I realized that I don't currently have a
backup meter, I suppose I could use this as an excuse to buy a true RMS
Fluke, I don't think I can bring myself to buy a cheapie, except

perhaps
as
a backup. Anyone run into this?


Is the fuse intact?


I assume so, I didn't do anything that would blow it, but other times the
fuse has blown it has not exhibited any unusual behavior. I know what I'm
doing, I tried all the simple stuff, something has failed.




If the fuse is blown you get a consistent reading of about 1 per cent of the
true reading.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/


  #18   Report Post  
Old February 4th 08, 11:16 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,572
Default Fluke 77 acting up



If the fuse is blown you get a consistent reading of about 1 per cent of
the
true reading.



That isn't anything like is going on here. If I set it to read low ohms for
example, it starts out at around 300 ohms, then ticks down steadily until
after a few seconds the continuity beeper activates and then it keeps going
down to -0.00. If I set it to the regular ohms range, the bargraph ticks
rapidly. AC volts reads a few millivolts regardless, haven't tried DC volts
yet.


  #19   Report Post  
Old February 5th 08, 01:56 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 191
Default Fluke 77 acting up

I bought a 73 from a pawn shop years ago and it started doing wierd
stuff right away . I found several cold solder joints here & there ..
been working fine ever sence .

My 83 shortly after new started goofing up . It was the rubber thing
that connects the screen . Later it would start making chirping sounds
when turned off . That was a switch on the back of the circuit board .
This meter sits in a desk drawer and seldome gets used , it still looks
like brand new . I thought Fluke was bullet proof .

  #20   Report Post  
Old February 5th 08, 01:58 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,572
Default Fluke 79 acting up



I want the 87-V I guess. I won't buy used though. While I got your
attention, do the digits on you 77 appear solid black? Mine look a bit
brownish and I don't remember if they were ever black. I've had it new
since around 1987 if memory serves me correctly.

There are a few authorized Fluke dealers within driving distance from me.
I guess I'll make some calls tomorrow and see what prices I can get. These
places don't sell to joe consumer so they usually have competitive
pricing.


I've only ever bought used, in this case it was a demo or some sort and
comes in the original box with accessories and warranty, I'm not gonna pay
another hundred bucks to get to break the shrinkwrap. I saw a surprising
number of new and nearly new Flukes on ebay, with many going substantially
below retail. For some silly reason, I dislike the new wedge shaped models
and prefer the classic style. I have no logical reason for that though as
it's a tool.

The digits are black on the 77, though some of the segments are a bit washed
out. I fixed that years ago by washing the zebra strips but it came back
eventually.




Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Panasonic DVD-S27 acting odd Mark Modrall Electronics Repair 8 June 4th 07 01:04 AM
A/C Thermostas Keep acting up Z28 Home Repair 4 August 16th 06 08:45 AM
DMM acting flaky ed Electronics Repair 3 February 15th 06 06:49 PM
Why do Fluke multimeter LCD displays fade? Any Fluke model immune? fancy nospam tunes Electronics Repair 6 February 2nd 05 09:09 PM
Help! Heating acting up coldguy Home Repair 11 January 9th 05 01:44 AM


All times are GMT +1. The time now is 01:25 PM.

Powered by vBulletin® Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Copyright 2004-2022 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"

 

Copyright © 2017