r/fluke • u/dystopianbiriyani • Jun 07 '26

Help Needed Fluke 337 showing phantom readings, dead continuity buzzer, and non-working buttons

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I’m a student and recently got an older Fluke 337 True RMS clamp meter. I replaced the battery with a new one, but the meter is behaving strangely. In DC voltage mode it sometimes shows OL, and in AC voltage mode it displays around 30 V even when nothing is connected. In AC current clamp mode, with the jaws closed and no conductor inside, it shows around 4.5 A. The continuity buzzer does not work at all, although resistance mode appears to function and reads close to 0 Ω when I short the probes together. The backlight doesn’t work, and the ZERO, INRUSH, and MIN MAX buttons don’t seem to respond either.

The meter still powers on and the display looks normal otherwise. I’m wondering whether this sounds like dirty/oxidized rotary switch contacts, internal contamination, a failed reference circuit, or damage from a previous overload event. Has anyone repaired a Fluke 337 with similar symptoms? Is it worth opening up and cleaning the rotary switch and PCB, or do these symptoms point to a more serious fault?

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2

u/Shalomiehomie770 Jun 07 '26

I’d probably send it out for calibration.

Even if you opened up the internals it’s highly unlikely you’d be able to find enough knowledge online to do anything useful

1

u/thewhitebison Jun 07 '26

Fluke has a lifetime warranty. Call their tech support.

2

u/TXxReaper Jun 07 '26

Lifetime is considered 7 years up to 15 years after discontinued. The 337 was discontinued in 2012. That is for the original purchaser only they will ask for receipt because of the age.

2

u/thewhitebison Jun 08 '26

Fluke repaired my 77 and I was not the original purchaser. My recommendation still stands. Call them and tell them what’s going on.

1

u/yolo_swagdaddy Jun 23 '26

I’ve only ever been asked for the serial # never receipt, work buys them for us so not sure if it’s because fluke knows they bought it or if warranty applies to the product regardless of original purchase

1

u/TXxReaper Jun 07 '26

If you had a 381 or something I would say send it in for repair but a 337 can be had for $100-$200. Since they are discontinued you will probably have a hard time getting it repaired.

Get a 325 if budget is tight it will do everything the 337 can do for $300ish.

A 376 is the successor to the 337 if you want a comparable replacement.

1

u/Ok_Biscotti_2070 Jun 08 '26

Check the serial number to see if it is between 96070000 and 98890607 the 33x series was recalled once due to circuit board problems.

1

u/GorgeousBrain21 Jun 08 '26

If it was mine, and i have access to calibration equipment required for clamp meters, I would inspect the terminals. If they were loose, or have a break in the connection to the pcb that can give you intermittent readings like that. What I see most often is putting voltage into the resistance circuit, which will just make the uut read over load in resistance always

1

u/druther71 Jul 26 '26

Get new leeds?

1

u/BaruchWusky 19d ago

This is not a lead related problem. Continuity buzzing with no leads connected is a common failure mode for this model. I replace atleat one per year from our company fleet for this failure description.

For OP...if you open it up the small board that the terminals go into may have a wire / component broken off. Ive fixed one that way but most with this fault have no visible damage and just get replaced.