Author Topic: Amprobe resistor identification  (Read 2224 times)

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Offline CaptnshackyTopic starter

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Amprobe resistor identification
« on: May 06, 2019, 11:43:52 am »
Could someone here help me identify this resistor? If it is even a resistor. Its directly solder to the positive lead trace of an Amprobe ACD -41PQ. I asked Digikey to identify and they say the color bands do not make any sense. Which is the same conclusion I got. Any help would be great. Thanks
 

Offline radiolistener

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Re: Amprobe resistor identification
« Reply #1 on: May 06, 2019, 12:01:44 pm »
according to color code calculator, this is 10.2 Ohm ±3% resistor:

https://www.allaboutcircuits.com/tools/resistor-color-code-calculator/
 
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Offline CaptnshackyTopic starter

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Re: Amprobe resistor identification
« Reply #2 on: May 06, 2019, 12:05:56 pm »
Thanks for the help. Would this be a 4 or 5 band color code? Just for my future reference.
 


Offline retiredcaps

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Re: Amprobe resistor identification
« Reply #4 on: May 06, 2019, 06:40:51 pm »
A picture of that resistor and its surrounding area might help us help you?
 

Online Andy Watson

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Re: Amprobe resistor identification
« Reply #5 on: May 06, 2019, 07:05:35 pm »
1k 5%.

Edit: I think the orange band is a voltage rating - 300V.
« Last Edit: May 06, 2019, 07:24:18 pm by Andy Watson »
 

Offline retiredcaps

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Re: Amprobe resistor identification
« Reply #6 on: May 06, 2019, 07:17:29 pm »
1k 5%.
That would be my guess as well if the resistor is part of the input protection.  Likely a fusible 1k resistor found in many higher end multimeters.

http://mrmodemhead.com/blog/fluke-87-fusible-resistor/

@Captnshacky, is that resistor open in your clamp meter?
 
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Offline Jwillis

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Re: Amprobe resistor identification
« Reply #7 on: May 06, 2019, 09:56:04 pm »
Although many resistor  code charts don't show orange as a tolerance, some do .Orange band is 3% tolerance

So the  resistor  is a 10.2 Ohm 3% tolerance
 

Online Andy Watson

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Re: Amprobe resistor identification
« Reply #8 on: May 07, 2019, 09:57:31 am »
Curious! To those advocating 10.2 at 3%, does it not worry you to be specifying three significant digits on a resistor that has 3% tolerence?
 

Online Zero999

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Re: Amprobe resistor identification
« Reply #9 on: May 07, 2019, 02:49:18 pm »
Curious! To those advocating 10.2 at 3%, does it not worry you to be specifying three significant digits on a resistor that has 3% tolerence?
I agree. It does sound strange. 10R2 is an E96 value, which is normally only used for 1% tolerance parts or better. I'd expect a 3% tolerance resistor to be an E24 value, with E48 being feasible, but not E96.

https://en.wikipedia.org/wiki/E_series_of_preferred_numbers#E24_vs._E48,_E96,_E192
 

Offline CaptnshackyTopic starter

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Re: Amprobe resistor identification
« Reply #10 on: May 07, 2019, 11:06:45 pm »
Here the entire pcb. Gold band was closet to the lead input or the left side of this pcb. Thanks guys
 

Offline CaptnshackyTopic starter

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Re: Amprobe resistor identification
« Reply #11 on: May 07, 2019, 11:16:18 pm »
1k 5%.
That would be my guess as well if the resistor is part of the input protection.  Likely a fusible 1k resistor found in many higher end multimeters.

http://mrmodemhead.com/blog/fluke-87-fusible-resistor/

@Captnshacky, is that resistor open in your clamp meter?

You may be correct. I would hate to send this to Amprobe for repair for a simple resistor swap....
 

Offline CaptnshackyTopic starter

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Offline retiredcaps

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Re: Amprobe resistor identification
« Reply #13 on: May 08, 2019, 06:14:42 am »
Does this look correct? Its a 1k 5%

https://www.mouser.com/ProductDetail/Vishay/NFR2500001001JA500?qs=%2Fha2pyFadujwYBQf3%252BFYSuuGxPDNPv1QpIGWG5vyaRjUWSvp39XiAA%3D%3D
The one you linked is 1/3 W.  Most fusible resistors in the input protection is 1W or 2W.  I suggest this one as per modemhead's blog

https://www.digikey.com/products/en?keywords=OY102KE

As a test to see if your clamp meter works, and assuming your existing resistor R2C is open (since you didn't answer me earlier), I would just put in a normal 1k resistor to test low voltage measurements like a 1.5V AA cell.  If that works, then order the replacement part.
« Last Edit: May 08, 2019, 06:18:02 am by retiredcaps »
 
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Offline CaptnshackyTopic starter

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Re: Amprobe resistor identification
« Reply #14 on: May 08, 2019, 10:37:56 am »
Does this look correct? Its a 1k 5%

https://www.mouser.com/ProductDetail/Vishay/NFR2500001001JA500?qs=%2Fha2pyFadujwYBQf3%252BFYSuuGxPDNPv1QpIGWG5vyaRjUWSvp39XiAA%3D%3D
The one you linked is 1/3 W.  Most fusible resistors in the input protection is 1W or 2W.  I suggest this one as per modemhead's blog

https://www.digikey.com/products/en?keywords=OY102KE

As a test to see if your clamp meter works, and assuming your existing resistor R2C is open (since you didn't answer me earlier), I would just put in a normal 1k resistor to test low voltage measurements like a 1.5V AA cell.  If that works, then order the replacement part.

Will it matter that its 10% and not 5%? Thanks
 

Offline David Hess

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Re: Amprobe resistor identification
« Reply #15 on: May 08, 2019, 08:18:11 pm »
Will it matter that its 10% and not 5%? Thanks

No, it will not matter.

I also think it is 1k 5%.  It is some sort of flame proof or fusible resistor for safety and overload protection.
 

Offline retiredcaps

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Re: Amprobe resistor identification
« Reply #16 on: May 08, 2019, 10:29:24 pm »
Will it matter that its 10% and not 5%? Thanks
Modemhead's blog that I linked tells you why.

http://mrmodemhead.com/blog/fluke-87-fusible-resistor/

"The replacement I’ve selected is a 1kΩ 2W Vishay metal-film fusible resistor.  It is 5% tolerance instead of the original 1%, but the value of this resistor does not affect the calibration.  (It is in series with the voltage divider’s 10 Meg input impedance, which far outweighs any variations in this resistor.)"
 
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Offline CaptnshackyTopic starter

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Re: Amprobe resistor identification
« Reply #17 on: May 08, 2019, 10:57:37 pm »
R2C is open. You assume correct. Thanks for the help
 

Offline retiredcaps

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Re: Amprobe resistor identification
« Reply #18 on: May 08, 2019, 11:05:22 pm »
Since RC2 is open, it's prudent and very quick, qucker for you test, than for me to write this out, PTC, SPG1, SPG2 and SPG3.

The PTC should be around 1k ohm.  SPG1, 2 and 3 should all measure open circuit.

 
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Offline CaptnshackyTopic starter

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Re: Amprobe resistor identification
« Reply #19 on: May 08, 2019, 11:11:57 pm »
Since RC2 is open, it's prudent and very quick, qucker for you test, than for me to write this out, PTC, SPG1, SPG2 and SPG3.

The PTC should be around 1k ohm.  SPG1, 2 and 3 should all measure open circuit.
all correct 1.7k ohms on PTC Thank you so much for the help.  :)
 

Offline retiredcaps

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Re: Amprobe resistor identification
« Reply #20 on: May 09, 2019, 05:08:56 am »
all correct 1.7k ohms on PTC Thank you so much for the help.  :)
1.7k ohm is in the ball park.  I just see Fluke use 1k to 1.1k ohm for their PTCs.  I wouldn't worry too much about 1.7k ohms.

I found a PTC in the 100k ohm range on one used/abused meter.
 


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