Review on the FLUKE 381 REMOTE DISPLAY TRMS CLAMP METER - Page 1
Forum section: electronics / testgear

author: DS-LABOR
author_rank: Newbie
timestamp: December 14, 2012, 09:12:51 pm
content: Hi all,find a review on the Fluke 381 attached as a PDF to this post. this is a quick review, and it will be updatet in the next few days...daveErrata: Page one on bottom: it should say: "It is not loose but since I know the quality of products like their multimeters, I am really disappointed in what they have done here"

author: saturation
author_rank: Super Contributor
timestamp: December 14, 2012, 09:50:17 pm
content: A very nice review, and well formatted ! Comments later when I finish it, but kudos for details, photos and readability.

author: ilikepez
author_rank: Regular Contributor
timestamp: December 16, 2012, 02:19:32 am
content: Yeah I really don't know how to feel about some of Flukes newer stuff.

author: kriwoel
author_rank: Newbie
timestamp: November 23, 2015, 09:17:36 pm
content: Hi,Any update about the review yet? no teardown and post some details inside the meter ?I got an used Fluke 381 from local pawnshop for 5 euros, unfortunately broken one, have blown its all input protections: PTCs, fuse, power resistors and have a big hole trough the outer back case. Someone' mistake using standard probe not the iFlex when measuring HVAC current. I'd already cleaned the PCB and repaired the plastic casing using 2-components plastic epoxy. The meter still turn ON and VDC/VAC still works fine but strange R/Continuity and of course I cannot check ADC/AAC.Maybe someone with F381 at hand can share picture of its input protection components. I need to replace components marked as RT1, RV1, RV2 ( PTC fuses), high wattage resistor R2 and some smd R27, F1 and CR3. And L1, L2 , L11 ( loops?).Thank you for any help in advance.

author: crispy_tofu
author_rank: Super Contributor
timestamp: November 23, 2015, 10:15:27 pm
content: L is the designator for inductor.

author: kriwoel
author_rank: Newbie
timestamp: November 24, 2015, 08:09:03 am
content: Yes, thanks, I'm just not sure what it could be before. I found some components from the debris, from the dimension its looks like the missing inductor and fuse (1206 with marking code A). Maybe they just pop off from the PCB when the PTC/MOV blown. I'm not an real EE actually, only know how to replacing components according to schematic diagram. And I found the meter still can measure IAC and IDC using the clamp.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 24, 2015, 11:37:28 pm
content: Quote from: kriwoel on November 23, 2015, 09:17:36 pm1) Does DCV and ACV actually give you good readings? For example, if you measure a 9V battery, do you get 9V on the lcd display?Quote2) Most Fluke front end input protection consists of the same components across several multimeters.3) Here is a picture of the clamp meter 374 fromhttps://www.eevblog.com/forum/repair/fluke-374-clamp-tester-diagrams-ohms-resistance-scale-fault/4) RT1 is your 1.1k ohm 1000V thermistor (PTC). RV1 and RV2 are likely 575V rated MOVs (same ones used in the Fluke 87V). R1 is a 1k ohm 2W fusible resistor. F1 is a fuse marked with the letter "A". R125 (8542) on the 374 might be a good guestimate for your 381's R27?5) For test purposes, you can put in any 1k ohm resistor for RT1 and R1 in the 381. Leave RV1 and RV2 unpopulated (meter will work without it, but not give you any input protection). If resistance readings work, then you can source the proper rated safety values for each.6) Put in a fuse for F1, 10k ohm resistor for R125 for test purposes. I have no idea for CR3 or the values of the inductors.