Huayi MS8229 5 in 1 multimeter teardown - Page 1
Forum section: electronics / testgear

author: Robomeds
author_rank: Frequent Contributor
timestamp: September 24, 2015, 04:11:42 pm
content: I recently bought this meter new off ebay for all of $15. I've seen these various 5 in 1 meters over the years and it seems several companies have MS8229 meters. This one didn't look like the others but the price was cheap enough that I figured I would give it a look. The seller was in the US and delivered quickly. I think there are some still listed for this price if any one wants one (it was a buy it now price). It seemed that other listings had these closer to $50 so the generally good impression the meter makes given that price might be due to a pricing error.This is an auto ranging meter with quite a few functions. We have the typical volts (AC/DC), resistance, current, diode, and continuity. It also has capacitance and frequency. The less usual features are the two temp measurement ranges (1C and 0.1C, either via the internal sensor or the thermocouple), relative humidity, sound level, and light intensity. The meter is 4000 count and the stated DCV accuracy was something like 0.8%+2 counts (off the top of my head). Basically it has the sort of specs you expect from a cheap meter.OK, on the outside the meter is generally what you expect for things in the $20 (internet) price range. The plastic is cheap feeling/sounding but the meter feels reasonably solid. The buttons are the rubber membrane kind. The probes felt surprisingly nice for the price. Again, if feels like they intended it to be 2-3x the price I bought it for. In addition to the probes it came with short alligator leads for capacitance testing and a thermocouple with red and black banana plugs. The printing is smudged in some places. The battery door is held with metal inserts and screws. The tilting stand is hard to get out but works well enough when out. The lack of rubber feet makes it hard to operate one handed as the meter just slides around. The screen is easy to read. The main switch feels cheap next to a Fluke but not much worst than the Brymen based meters I've used.I did just some basic accuracy testing with the thing before tearing it down. I'm actually rather impressed. In DC, AC and resistance ranges it was very close to my Fluke 187 readings. The screen update rate seems to be about 3 per second. The auto ranging isn't Fluke fast but pretty good. Perhaps 2 seconds to go from open circuit to shorted in the resistance range. Speaking of resistance, I think they added a fudge factor to zero out the probes. The meter reads 0.0 ohms when you short the leads. The same leads read 0.3 or so in my 187 when I short them. Still, it gave me readings that were very close to my 187 when checking some resistors I had around. The backlight only stays on for 10 seconds or so then fades out. Pity as it works really well. Overall the meter gives the impression of a cheap meter that was carefully adjusted before being sold. These readings agreed with my 187 as well as my Greenlee DM200A (based on the non-RMS Brymen 257 family).So what's inside?Well most of the guts are what you would expect in a cheap meter. The construction is tolerable. Not Centech cheap but cheap. The input protection is very limited and certainly doesn't hit the CAT III 600V claim. There is a place for a 10A fuse but it was bypassed on this unit (and labeled as such on the outside). However, I was suprised that the 1/2 amp fuse is an 600V rated ceramic fuse. There is also a PTC and some diodes to protect the input...The housing does have a grove around the sides but not where the front panel slopes to become the top and bottom of the meter. I noticed that one of the screw bosses that holds the PCB was cracked.The meter has a lot of trim resistors. The largest label I found was VR13. I have no idea what each trimmer does so adjusting things in the future might be questionable.The sensors at the top of the meter don't look like much but I don't really know what to expect out of a humidity sensor.Anyway, for $15 I can't feel cheated. I'll probably use the thing for some light and sound level measurements more than anything else.(no proof readers were harmed or even notified during the creation of this post)

author: Robomeds
author_rank: Frequent Contributor
timestamp: September 24, 2015, 04:15:33 pm
content: More pics:

author: retiredcaps
author_rank: Super Contributor
timestamp: September 24, 2015, 05:24:33 pm
content: Thanks for the review and pictures. It looks like a Mastech VA19E (as seen on pcb)http://mastech.com.cn/html/en/products-va19.htm$15 + free ship is a good price for it.

author: Robomeds
author_rank: Frequent Contributor
timestamp: September 24, 2015, 08:15:26 pm
content: Yeah, that looks like the same thing. I just took the thing for a ride in my car. Not sure I trust the sound level meter. In my living room with basically nothing on it shows 66db. Yes, my laptop fan isn't silent but it's pretty darn quite. In my car on the freeway it was showing 96db. Now my car is a convertible with little sound deadening but it's also bone stock. On this list no car's interior is over 90db. Unfortunately I don't think I can easily calibrate the sound level meter. Pity since even the temp meter was is good agreement with my other meters.

author: Fungus
author_rank: Super Contributor
timestamp: September 24, 2015, 08:43:45 pm
content: Quote from: Robomeds on September 24, 2015, 04:11:42 pmSeller? Auction link...??Quote from: Robomeds on September 24, 2015, 04:11:42 pmI don't think there's any way that PCB belongs to a $15 meter - look at all those chips!

author: Robomeds
author_rank: Frequent Contributor
timestamp: September 24, 2015, 08:52:28 pm
content: Quote from: Fungus on September 24, 2015, 08:43:45 pmHere is a link to the auctionhttp://www.ebay.com/itm/161829150674?_trksid=p2060353.m1438.l2648&ssPageName=STRK%3AMEBIDX%3AIT

author: icpart
author_rank: Regular Contributor
timestamp: September 24, 2015, 09:06:38 pm
content: Hi guys.I have the same 5in1 V&A 19 multimeter and tomorrow I can post some pictures from inside of my multimeter for comparison vs that Huayi branded multimeter. It will be interesting to compare that multimeters. That multimeter Huayi seems to be very cheap in USA.For comparison the price of VA19 in Europe is around 41EUR.

author: Robomeds
author_rank: Frequent Contributor
timestamp: September 24, 2015, 11:23:44 pm
content: Quote from: icpart on September 24, 2015, 09:06:38 pmThe 41EUR price sounds about in line with most of the prices I saw on Ebay. I think it's just a fluke () that this seller is listing the thing for $15.

author: icpart
author_rank: Regular Contributor
timestamp: September 26, 2015, 08:31:10 am
content: Hi I have posted some pictures inside my VA19. The PCB layout seems to be similar to PCB of that Huayi multimeter. Also from your pictures seems that PCB quality is not very good. I also have another cheap multimeter with that crap looking PCB like of the Huayi multimeter. The PCB of VA19 seems to be a little better quality compared to MS8229.Also on mine multimeter there are huge trim pots if we compare them against trimpots on Huayi PCB. Also mine multimeter is 7 years old.

author: amirm
author_rank: Regular Contributor
timestamp: September 26, 2015, 04:06:11 pm
content: Quote from: Robomeds on September 24, 2015, 08:15:26 pmYou can't trust any of these SPL meters to tell you how loud your environment is. Much of what they detect is low frequencies which your ear is not very sensitive to. I wrote an article on this which you can read here:http://www.madronadigital.com/Library/RoomDynamicRange.html. It is targeted toward audiophiles but the explanation is there for this use also.

author: radhaz
author_rank: Regular Contributor
timestamp: September 26, 2015, 04:12:59 pm
content: What microphone element is used in these meters? It looks like a piezo.

author: Fungus
author_rank: Super Contributor
timestamp: September 26, 2015, 06:07:44 pm
content: Quote from: Robomeds on September 24, 2015, 08:52:28 pm"Does not ship to Spain"It has to be said it's a completely different shape to all the other "MS8229"s on eBay.

author: kanareks
author_rank: Newbie
timestamp: January 26, 2018, 11:49:47 am
content: Dear Robomeds,I know it's an old topic, but maybe you still have this multimeter. I need to replace resistor R46 (marked on the picture). Could you check its value for me please?

author: retiredcaps
author_rank: Super Contributor
timestamp: January 26, 2018, 10:39:38 pm
content: Quote from: kanareks on January 26, 2018, 11:49:47 amWhat is wrong with that resistor? Is it open? What is its color code?

author: kanareks
author_rank: Newbie
timestamp: January 28, 2018, 02:49:38 pm
content: Resistor burned out, I am unable to read its color code. I have found your pictures, but only if they will be in different angle I would be able to read its color codes.

author: retiredcaps
author_rank: Super Contributor
timestamp: January 28, 2018, 06:45:29 pm
content: I don't have time today, but search the Internet for MS8229 images or teardown and see if someone else posted a picture where you can see the resistor color band.This meter is originally made by Mastech.

author: Robomeds
author_rank: Frequent Contributor
timestamp: February 02, 2018, 02:33:01 am
content: Kanareks,I do still have the meter. Give me the weekend and I will try to get a better picture for you.

author: Robomeds
author_rank: Frequent Contributor
timestamp: February 03, 2018, 01:25:00 am
content: It's a 300 ohm, 1% resistor (orange-black-black-black-brown).

author: kanareks
author_rank: Newbie
timestamp: February 06, 2018, 09:10:58 am
content: Thank You so much, I will let you know if replacing it will fix the device.