Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: dude on March 14, 2020, 12:15:18 pm
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I blew my manual meter by checking for bias current, had reversed a diode and runaway bias current while it was in test probes. Meter was on the 200m setting and the test probes read over 500m bouncing around for a few seconds only, before it blew. The fuse went, only one fuse, .875 amp. replacing the fuse didn't bring the meter back.
It's not completely dead, only continuity function works, but it read .000 KHz all the time, never see the OL as usual. Every setting reads 0.00 (manual dial) and nothing works except continuity.
Pitch it, or fix it....? If I attempt a fix where would be first place to look?
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Are we allowed a clue WHAT kind of meter this is? Some may be fixable. Some aren't. Some may be but it isn't worth yout time at today's prices.
What is "200m"?? milliAmps? milliVolts? MegaVolts? milliFarads?
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Sorry, here an inside and dial picture, the 200m as it says on the meter dial is mA's. I had much more current then 200 mAs when it went, the fuse is not the right side but is the right value, if I get it working I'll replace the correct fuse. I know these meters a a dime a dozen but I like the cap feature, those auto meters are not accurate on P readings.
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guts
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fwiw
In the 'ol days I could send my Fluke back for calibration/ re-certification. I went surfing awhile back n couldn't find anywhere to send it. Did find a repair place, but it was $50 less than a new 87 :think1:
mine works fine, I just get twitchy from days of old seeing a cal sticker 8yrs past due :icon_biggrin:
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I remember when you could send a 87V back to Fluke and they would repair it for a flat $95.
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:laugh:
I remember when
I find I say that a lot :icon_biggrin:
The new world; $300+ repair, fluke 87W $395-ish
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Time for a new meter, the only thing l hate about auto ranging is the pico reading, never accurate.
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auto ranging
then get one that lets you do both. Both mine have a range button, you can however smoke 'em using that feature :icon_biggrin:
the old black fluke VTVM's didn't auto-range, you could hear the needle slap the stops from 30 feet :laugh:
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I always read bias milliamps with meter set to volts or milli-volts with test probe each side of a 1 ohms resistor.
Using voltmeter milliamps scale is not safe for the meter. I blew two time a $15 fuse on my Fluke. Meter is ok. Now I know.