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9205(2)A multimeter

john douglas

Oct 11, 2018
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I have a multimeter Excel DT-9205(2) A. While measuring resistance in the circuit,the probe accidentally touched the positive voltage.Since then whenever I tried to switch on the multimeter , lcd display showed digit for a second and disappeared.On carefully examining the IC near the on/off switch is seemed to be burnt and the ic number is impossible to read .I will be very grateful if anybody can IMG_20180929_134222.jpg suggest the IC number and circuit diagram to repair my multimeter.Thanks in advance.
 

73's de Edd

Aug 21, 2015
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Sir john douglas . . . .

Related to damage from voltage misapplication a TL062 is most suspect.

That units schematic shows two LM358 flat packs being used in the capacitor test function.
A HARRIS version of a LM358 . . .17358 . . . is being used in a power supply function
On your photo, one of the visible I.C.'s is showing a ST manufacturer, but the units critical identifier is being hidden by the right one, of the two GREEN poly capacitors, the visible info marking is probably being a code date, on the end, relating to the manufacturing date of that chip, suggesting, it possibly being the 35th week of 2005 or 2015.
BUT . . . the closest IC to the power switch in the top corner is a TL062.with an associated C20 and D7 nearby.


CLARIFIED SCHEMATIC . . . . . DT9205
upload_2018-10-12_3-40-26.png

73's de Edd
.....
 
Last edited:

Bluejets

Oct 5, 2014
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I have a multimeter Excel DT-9205(2) A. While measuring resistance in the circuit,the probe accidentally touched the positive voltage.Since then whenever I tried to switch on the multimeter , lcd display showed digit for a second and disappeared.On carefully examining the IC near the on/off switch is seemed to be burnt and the ic number is impossible to read .I will be very grateful if anybody can View attachment 43346 suggest the IC number and circuit diagram to repair my multimeter.Thanks in advance.
You do realise a new one is $15.00?
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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In Cambodia $15.00 may be equivalent to a month's earnings. And this multimeter may be difficult to purchase online without a long wait for delivery to the OP's country. However, I doubt it can be economically repaired unless the components required can be obtained for free. Best to replace it if possible and move on with your life.
 

john douglas

Oct 11, 2018
3
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Oct 11, 2018
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Dear sir 73's de Edd
The second ic is 324 a ST manufacturer near two green poly capacitor.Please I need the number of first ic near on /off switch (red encircled) which seems to be burnt out.Thanks sirIMG_20180929_134206.jpg IMG_20180929_132006sc.jpg
 

john douglas

Oct 11, 2018
3
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Oct 11, 2018
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Dear sir as you suggested closest IC near to power switch is TL 062 , BUT http://www.ti.com/lit/ds/symlink/tl062.pdf shows TL062 has total 8 pins (4 on each side) whereas the ic burnt ( encircled red ) has total 14 pins (7 on each side). So I think it is different ic .Hoping the answer from you.
 
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