Innova 3320 Multimeter teardown - Page 1
Forum section: electronics / testgear

author: Robomeds
author_rank: Frequent Contributor
timestamp: July 04, 2013, 06:19:58 am
content: This isn't going to be much of a review but I thought people might appreciate another meter teardown. This time it's a cheapie, the Innova 3320. By cheapie I mean $20 from Amazon.First, on the outside:The meter is quite small. I think it looks bigger in pictures. The controls are very basic... just that knob in the center. The large display is quite easy to read though the contrast isn't the best, just decent. I like the clips for the leads as well as the strap on the back which lets you strap the meter to your wrist when working in tight areas or with both hands (I wouldn't try that where power and safety is a concern).The auto ranging is reasonably quick though not really fast. The continuity check is on the slow end of things. Accuracy specs seem OK for a cheap meter. (1%+5 counts DC). The under load battery check is nice though I don't know how much I would ever use it. Battery replacement is poor as you have to remove the back half of the meter. The screws of course are self tapping thus you have to be careful to avoid cross threading.The probes are quite cheap feeling. The tips aren't that sharp and the main part of the barrel doesn't seem to make good contact. The 10 A range is unfused. The box is rather funny. They show someone taking a voltage measurement with the positive lead in the 10A range. The measurement in the picture is of an AC outlet! Good thing the picture was staged! A 15A, 120V line might hurt someone...So what about the inside? Cheap again. A single fuse for the shared voltage/current input. The 10A is unfused. The meter claims Cat 2 but with no fuse on the 10A I don't know if that is really OK. I certainly doubt the glass fuse is rated to 600V. A single PTC seems to handle an over voltage condition. It does have a few isolation cuts in the PCB.All around I would feel better about recommending this as a cheap meter if it had a 10A range. Most of it works well enough for the simple home user but I don't like the idea that they might put the leads in the wrong holes and discover the mistake the hard way.

author: Robomeds
author_rank: Frequent Contributor
timestamp: July 04, 2013, 06:51:47 am
content: And the last pics

author: retiredcaps
author_rank: Super Contributor
timestamp: July 04, 2013, 08:06:20 am
content: Thanks for the teardown and mini-review. Keep them coming.I can't remember if this exact model, but some places in Canada sell this for $49.95 MSRP CDN and then have it on "sale" for $24.99 or $14.99, making it look like a good deal.We get hosed (pun intended) for pricing here in Canada even though the Canadian dollar has been at par or better for a few years now.

author: ModemHead
author_rank: Frequent Contributor
timestamp: July 04, 2013, 12:05:56 pm
content: Wow, they couldn't be bothered to put some spaghetti on the bare R31 lead? Or at least re-orient it so that it isn't right on top of those SMD components.

author: z11aalex
author_rank: Newbie
timestamp: January 08, 2014, 10:06:05 am
content: I purchased one, and as being a beginner I accidentally shorted in mA. However on the box it is stated 200mA fused and the fuse itself it is 5mA. Is that correct cause I do not get it.It is still functioning voltage, resistance but no current. Do I need to buy a fuse as stated 5mA or 200mA. Thanx and sorry for dumb question.

author: Tube_Dude
author_rank: Regular Contributor
timestamp: January 08, 2014, 08:10:08 pm
content: From the pic, it look's like a T315mA ( T means slow blow )....

author: Wytnucls
author_rank: Super Contributor
timestamp: January 08, 2014, 10:19:38 pm
content: A slow blow fuse in a multimeter sounds like madness. I would replace that one with a fast blow fuse (FF) with a rating of 200 mA or slightly higher.

author: retiredcaps
author_rank: Super Contributor
timestamp: January 08, 2014, 11:13:03 pm
content: The online manual for the multimeter says it is 315mA and even gives part numbers and vendors.

author: fifty442
author_rank: Newbie
timestamp: November 14, 2014, 10:54:38 pm
content: Thank you for the teardown/review. Do you have a picture that shows the contacts located on the back side of the selector wheel by any chance?