Troubleshoot M92A Multimeter - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th May 2008, 05:45 AM   #1
haseeb is offline haseeb  India
diyAudio Member
 
Join Date: Feb 2008
Send a message via Yahoo to haseeb
Default Troubleshoot M92A Multimeter

Hi Guys,

Is there any body who knows about the multimeter Model M92A.

I am having a problem with ma functionality of my multimeter.

Any body has the schematics for this model.

I am attaching the device picture the right side device in the picture is my model.

Regards,
Haseeb
Attached Images
File Type: jpg mastech_92aa.jpg (70.7 KB, 98 views)
  Reply With Quote
Old 30th May 2008, 11:32 AM   #2
Mooly is online now Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Hi,
If it's just the ma range I would guess at either an internal fuse, open circuit shunt resistors or open circuit print in that order.
What have you been measuring
  Reply With Quote
Old 30th May 2008, 12:05 PM   #3
oshifis is offline oshifis  Hungary
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
These little bastards can be very easily destroyed by meausuring voltage when the DMM is in resistance setting. Fortunately, replacing the 7106 chip generally cures the problem.
  Reply With Quote
Old 30th May 2008, 04:06 PM   #4
Minion is offline Minion  Canada
diyAudio Member
 
Join Date: May 2006
Location: Cowican Bay , vancouver island
Also in case you didn"t know , some multimeters have the Probes going into different holes for the Ma Function.... At least mine does...


Cheers
  Reply With Quote
Old 3rd June 2008, 01:49 AM   #5
haseeb is offline haseeb  India
diyAudio Member
 
Join Date: Feb 2008
Send a message via Yahoo to haseeb
Thanks guys for responding.

I was actually measuring the tail current in the input stage of my power amp project.

I checked the fuse and it is fine.

mooly: can you please eloborate "open circuit shunt resistors "


oshifis : I did not check what chips my multimeter has but I'll check and try to replace, if it is the same.

oshifs , will my Ampere fuctionality still be available?, if 7106 chip gets blown ...
  Reply With Quote
Old 3rd June 2008, 06:19 AM   #6
oshifis is offline oshifis  Hungary
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
Haseeb,

If only the mA is wrong, but resistance and voltage is OK, then the chip is good. Maybe one of the current sensing precision resistors is broken. You need another DMM to measure them one by one.

BTW, the 7106 chip (originally coming from Intersil as ICL7106) has many different names with the same pinout and functionality. They are interchangeable, regardless what is printed on them. Maxim also produces it.
  Reply With Quote
Old 3rd June 2008, 06:26 AM   #7
Mooly is online now Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Hi,
A DVM is really just a millivolt-meter. When you measure current you are actually measuring the volt drop across a known resistor- the shunt resistor - and there will be a few of these selected by the function switch, depending on what range you are on.
See www.kitsrus.com/pdf/7106.pdf for a data sheet.
If all other ranges work I would have thought the 7106 would be O.K.
  Reply With Quote
Old 3rd June 2008, 09:27 AM   #8
haseeb is offline haseeb  India
diyAudio Member
 
Join Date: Feb 2008
Send a message via Yahoo to haseeb
Guys thanks for the suggessions and inputs.

I will post once after my findings and troubleshoot.

Regards,
Haseeb
  Reply With Quote
Old 4th June 2008, 04:55 AM   #9
haseeb is offline haseeb  India
diyAudio Member
 
Join Date: Feb 2008
Send a message via Yahoo to haseeb
Guys,

I could not figure out the fault in my device.

Every thing looks fine, I did not dare to do RND on this because only problem with my device is ma functionality else every thing is fine Ampere,ohm,volts etc.

I tried to figure out the pcb components routed through the ma connector,but the traces were rounted almost all board.

decided to keep quit until I loose all the functionality of my meter.

Regards,
Haseeb
  Reply With Quote
Old 4th June 2008, 07:54 AM   #10
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
silly I know , but - did you checked the fuse ( if any is present inside ) ?
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
System Troubleshoot: Need Help ronfi Analogue Source 2 17th October 2008 10:07 PM
Help me troubleshoot this design, please teemuk Solid State 19 7th August 2006 10:07 PM
Technics SL-J90 troubleshoot Samson Analogue Source 1 30th December 2004 09:53 AM
My P68 sub amp just went poof - help me fix/troubleshoot it! Jonathan M Solid State 21 23rd December 2002 07:08 PM
Help - Troubleshoot arkay Tubes / Valves 16 5th January 2002 05:53 AM


New To Site? Need Help?

All times are GMT. The time now is 01:54 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2