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Very nice tester. I have several of these in different brands. I really like this one the most. It has more features then the others packed into one unit. Smd test pads. Direct testing via the multi slot for transistors, caps, resistors , fetts, etc. It can discharge caps completely before testing and also has test leads for quick in circuit testing when possible. The dc input socket is a big plus . You don't kill the batteries if you're doing multiple testing for long periods. Every one i have gets some wonky measurements when the internal batteries get low. Its my go to out of the 5 I have. The others have the locking sockets that tend to wear out fairly quicly and putting grabber leads into them is a pain. This is a very nice solid tester. Even has an average capacitor esr chart on the back for different uf or voltage electrolytics. Bought it over 6 months ago and its still going strong.
There are many features which may seem valuable to many users. Temperature was within a couple degrees at room temperature. Resistance, capacitance, frequency, ac & dc voltages were all respectable. I however was concerned with DC current. Our car had excessive at rest current drain. By inserting ammeter I was getting 0.76A. Shop manual says no production car should draw more than 50ma. Was hoping to use this meter to troubleshoot since inserting current meters in circuits is tedious. Spec says 3% +5 counts. Resolution is 1 ma but drift was better than .1A over less than 5 minutes. Even zero button was not stable enough to give true zero repeatedly. Zero drift was more than 80ma per minute making meaningful readings impossible. It is an adequate handy tester, but mine was not capable of accurate dc current clamp-on measurements. Many of the reviews associated with this meter are not for the acm91. I'm thinking the average indicated is misleading. Hence my dismal rating.
I unboxed the unit and tried to turn it on. Nothing happened at all. Batteries were so dead that the display couldn't even show Low Battery warning. Luckily I have spare batteries handy. Works fine with new batteries. The old batteries showed -.8 V and +1.9 V. And, no I didn't have my meter leads backwards on 1 of the batteries. I've been an electronics tech for 50 years and know how to check batteries. I bought the meter to carry in my computer case. All my other meters are old school and way too big for the case. My only complaint about the meter so far is that there's no back light. The built in flash light will help with the connections, but if it's semi dark you can't see the screen.
This only comes with two probes, and it's basically unusable with the socket. It's impossible to insert a component without just bending the pins, and since it only comes with two probes, I don't think it's going to be useful. Also, the item I received appeared to be used and repackaged. It had several scratches and was packaged incorrectly.
my first LCR meter...i could not afford one before, it's very nice unit...the manufacturer must be very well organized and have very attentive and efficient employees to make these at such a reasonable cost..