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Products => Other Equipment & Products => Topic started by: funnel on November 11, 2013, 05:02:31 pm

Title: Multimeter Amprobe broken help
Post by: funnel on November 11, 2013, 05:02:31 pm

I need help figuring out what is wrong with my multimeter. It's an Amprobe 240. I don't know how it happened exatcly but the knob was acting weird for a few weeks with the screen going on and off when selecting the DC function. You can see in the attached picture the burnt trace I cleaned but didn't help. Without measuring anything the multimeter is showing 1.052 V DC, 25.86 kOhm, and 144.1 uA. I also get wrong readings for resistors using the relative button.

Anybody knows how to find out what's wrong? Can I fix it or is the main chip toast?

Thanks.

Title: Re: Multimeter Amprobe broken help
Post by: retiredcaps on November 11, 2013, 05:26:42 pm

Check the PTC right by the volt jack.  It should be around 1 kohm.

Check your burnt trace to make sure it is not conductive as per

http://mrmodemhead.com/blog/ideal-carbon-footprint/ (http://mrmodemhead.com/blog/ideal-carbon-footprint/)

Title: Re: Multimeter Amprobe broken help
Post by: funnel on November 11, 2013, 05:51:59 pm

Wow. Thank you. I scraped the carbon with an exacto knife and now it works perfectly. Thank you.

Title: Re: Multimeter Amprobe broken help
Post by: retiredcaps on November 11, 2013, 06:45:38 pm

I'm glad you got it working, but all credit/kudo should go to modemhead for taking the time to document and photograph the repair for everyone's benefit.