# What can be the result if a resistor has less resistence in circuit?

Discussion in 'General Electronics Chat' started by frank55, Dec 5, 2015.

1. ### frank55 Thread Starter Member

Dec 6, 2013
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Hi guys if i have a SM resistor that should measures 100K and only measures 4K inm circuit on a power supply, what would be the symptoms?

2. ### kubeek AAC Fanatic!

Sep 20, 2005
4,688
806
You just said that, the symptoms are that you are measuring 4K instead of 100K. The reason most likely is that there are other elements in the circuit which means you are not mesuring only the resistor but a whole bunch of other components as well. Try taking it out of the circuit and measuring again.

3. ### frank55 Thread Starter Member

Dec 6, 2013
256
10

thanks but if i take it out and it measures only 4K instead of 100K ?also i have another same 100k in parallel and it gets the right resistance which is about 100K

4. ### dl324 Distinguished Member

Mar 30, 2015
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Other resistances in parallel with the 100K resistor... Remove one end to get an accurate measurement.

5. ### dl324 Distinguished Member

Mar 30, 2015
3,377
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It would help if you posted a schematic.

Apr 5, 2008
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7. ### dl324 Distinguished Member

Mar 30, 2015
3,377
651
Ah! SM in this context means Surface Mount, not SMall... I've never seen them referred to as SM; only SMT and SMD...

Obviously lifting one end is not possible...

Dec 6, 2013
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9. ### ian field Distinguished Member

Oct 27, 2012
4,447
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As everyone else mentioned - other components will conspire to give a low resistance reading in circuit.

Usually - resistors are more likely fail by going open or high resistance - if it read high in circuit, you'd know there was a problem.

Its not impossible for a resistor to fail low - but they usually show signs like scorching.

Dec 6, 2013
256
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thanks

11. ### WBahn Moderator

Mar 31, 2012
18,085
4,917
If they are truly in parallel, then you should be getting the same measurement for both. Why? Because they are in parallel!

So it's pretty clear that they are NOT in parallel. What makes you think they are?

12. ### frank55 Thread Starter Member

Dec 6, 2013
256
10

Thanks WBhn; well i'm not 100% sure, maybe you can figure it out for me and help, this is an LCD Samsung Monitor 2493 HM that i found out in the curve on the street,it has a steady blue light when i turn it on with black screen, i have no 24v to inverter and no 5.3v to the main board ,

so i took out the power supply board and connect by itself , the Big black Cap in the middle has 167v and IC801S pin 2 cc to gnd 10.60v it's too low i think ,i also cleaned all the hard glues that some say it's an issue.

checked all caps with a CapAnalyzer 88A and all other components that can be checked with a Fluke 87 DM and nothing seems to be out of order,

here some pic of the power supply.

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13. ### frank55 Thread Starter Member

Dec 6, 2013
256
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Hi WBahn; any more tips on this power supply fault? thanks

14. ### frank55 Thread Starter Member

Dec 6, 2013
256
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H guys new update on Samsung 2493 HM monitor.

Today i decided to reassemble power supply after taken out Cap 4pf 1KV
clean hard glue and re-solder it back also cleaned all other glue around all other caps,
and for my surprise i have tv on but with no controls and just a screen with switching back and forth between RGB ,white,and blue screen,with no controls on the front,just power on and of switch,see video,
what do you see of this?

I connected HDMI cable and i get sound also

Last edited: Dec 7, 2015

Dec 6, 2013
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16. ### frank55 Thread Starter Member

Dec 6, 2013
256
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You don't have to bother with my monitor no more,i found a bad solder and fixed it.

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