Author Topic: Mastech MS-8233E, MS-8240D and MS-8250C  (Read 12111 times)

iloveelectronics

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Mastech MS-8233E, MS-8240D and MS-8250C
« on: November 06, 2012, 11:42:13 PM »
Since opening my own eBay store I've been out trying to source electronics stuff that I can sell at reasonable prices. Obviously being located in Hong Kong my sources would be from China. Mastech is one of those Chinese companies that make a lot of multimeters either under their own brand or rebadged as others. Martin reviewed the MS-8218 on his YouTube channel that I sent him but despite being very accurate there are a few too many negatives going against it. So I continued the search and found these 3 other Mastech at different price ranges. They are rather rare and hard to find and I had to basically contact the manufacturer directly and special order them (at much higher than normal prices unfortunately).

MS-8233E - This is the auto ranging and more feature packed version of the much more common 8233A/B/C variants (easily found on eBay), at a beginner's price point. This E variant is rebadged as the Klein Tools MM200 in the US market, available at Amazon for <$35. EDIT: After looking closer it appears the MM200 is actually slightly different from the 8233E. It doesn't have the NCV detector and it has the frequency/duty cycle measurement in place of the Max Hold feature on the 8233E.

MS-8250C - I haven't been able to find any rebadged version of this meter but what caught my eye first was its appearance which for some reason I really really like. The C variant of the 8250 also features a dual display, non-contact voltage detector, USB interface etc. Its rather unique 6600-count also led me to believe it's running the same chip as the BK Precision BK2709B which won Dave Jones' $100 multimeter shootout 2 years ago.

MS-8240D - This is the mysterious brother of the Uni-T UT61E which some people knew existed but rarely (if ever) seen in real life! It uses the same Cyrustek ES51922A chip that the UT61E uses, so basically it offers the same performance, accuracy and resolution. What sets it apart from the UT61E is that it has implemented most of the features that the UT61E lacks, namely the backlight, MAX/MIN (besides PEAK), Auto Power Off and ability to turn off USB data logging. It also comes default with a USB cable instead of the RS-232 for the UT61E. It is rebadged as the PeakTech 3430 in Germany.

Here's a picture of the 3 meters together with the UT-61E. I'll post a very brief review of them later.

« Last Edit: November 07, 2012, 11:24:18 AM by iloveelectronics »
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iloveelectronics

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #1 on: November 07, 2012, 08:15:46 AM »
MS-8233E

Pros:
1. Exceptionally clear high contrast display.
2. Very compact in size. About the size of a modern large screen smartphone (much thicker though of course).
3. Removable holster.
4. Decent quality leads (for its price) with ratings marked on the probes and wires.
5. Very positive feeling range switch. Nice click-clacking!
6. Good display refresh rate at >3 times per second.
7. Feature rich for its size and price. Autoranging, max hold, backlight, temperature in both C and F scales, non-contact voltage detection.
8. Auto ranges the entire voltage range, no need to select between V or mV.
9. Fast voltage auto ranging.
10. Tilting bail allows 2 tilting angles.
11. Good DC and resistance accuracy (based on DMMcheck Plus/PentaRef and comparison to my Brymen 867).

Cons:
1. Only 2000 counts.
2. Slow continuity tester. Not the slowest I've seen but slow nonetheless.
3. Slow resistance auto ranging.
4. No bar graph display.
5. mA range shares the same socket as V and other measurements.
6. AC V measurement was way out (10%) on the 5VAC output on my DMMcheck Plus. Mains voltage measurement was fine though.
7. No true RMS. Perhaps that's what leads to the problem in (6) above? Can't really expect TRMS at this price point I suppose.
8. Diode tester doesn't work on LED's.
9. Jumper wires connecting the NCV indicator and LCD gingerly soldered onto the main board.
10. Only uses a 9V battery clip. But at least the wires are connected in a way that prevents too much stress on the joints.
11. Cat II 600V rated only. And current inputs are rated (and fused) at 250V only.

Overall I think (I may be biased) it's a very decent meter in the sub-40 dollar price range. Things like bar graph and true RMS you can't really expect from a low end meter like this anyway. It performs quite well and quick otherwise.
« Last Edit: November 07, 2012, 08:28:18 AM by iloveelectronics »
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Kiriakos GR

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #2 on: November 07, 2012, 09:37:03 AM »
I do not think that posts like this is what Martin had in mind as product reviews.

The poorly made Mastech its not an attraction magnet, but thanks for the pictures.
By the way tell to Mastech that the Europeans favor only the complete  packaged IC's .   

iloveelectronics

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #3 on: November 07, 2012, 11:17:41 AM »
I do not think that posts like this is what Martin had in mind as product reviews.

That's why I said it was just going to be a "brief review". I don't pretend to know enough nor do I have the proper equipments to do a proper product review. I was just trying to highlight some of the good and bad things I noticed. Hopefully a few people would still find it somewhat useful.
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iloveelectronics

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #4 on: November 07, 2012, 11:45:25 PM »
MS-8250C

Pros:
1. Very nice tough looking appearance. This is a very personal thing, I just really like the straight lines, angles and layout on this meter. Holds very nicely in the hand too.
2. Excellent range switch with ball bearing mechanism.
3. Easy access to fuses and battery with metal threaded screw receivers. (The 8233E also has metal threaded screw receiver for the battery compartment with I forgot to mention)
4. Lightning fast continuity tester.
5. Lightning fast autoranging, for both voltage and resistance.
6. Down to 1pF resolution for capacitance measurement. I don't have the equipment to test its accuracy but readings from basic ceramic and electrolytic caps look well within spec.
7. Very nice and even white backlight.
8. Doesn't have the Fluke Auto Hold but features the same "delayed hold" found on the UT61E for handsfree operation, by holding the HOLD button for a couple of seconds.
9. Dual display for measuring AC voltage/current and frequency, or frequency and duty cycle at the same time.
10. Built-in RS-232 to USB interface conversion with CP2102. Optically isolated with 2 pairs of infrared LED's and photodiodes. 2-way communication maybe?
11. Auto detects the USB connection so no need to push any button for enabling/disabling PC data logging.
12. Very good sensitive and accurate NCV detector (much more sensitive than the one on the 8233E).


Cons:
1. Display doesn't have very good contrast, looks a bit washed out when viewed directly. No problem when viewed at a slight angle.
2. Defaults to AC on all voltage and current ranges.
3. Software that comes with it is really basic.
4. Weak input protection. Only 3 PTC's, no MOV's or power resisters.
5. Only 6600 counts (which is actually quite sufficient for normal use).
6. Also only uses a 9V battery clip.

I thought the MS8250C used the same main chip as the BK2709B which Dave reviewed in his $100 multimeter shootout video, but I was wrong. It uses a Chinese made Silan SC7968 and I can't find any datasheet on the internet. EDIT: Someone over at the EEVblog forum pointed out that the SC7968 is actually a Cyrustek ES51968 ripoff.

I just found that DealExtreme actually has this meter for sale at a similar price point as the UT61E. I don't think I can beat them on the price even if I manage to source some for my eBay store. Apart from the number of counts this meter actually compares quite well against the UT61E in terms of performance and features. However, the lack of datasheet for the main chip probably means it's hard to find/write custom software to replace the very basic one that comes with it. EDIT: Again, now that we know it's basically equivalent to the Cyrustek ES51968 finding a datasheet isn't a problem anymore.
« Last Edit: November 08, 2012, 09:04:49 AM by iloveelectronics »
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MJLorton

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #5 on: November 08, 2012, 04:15:18 PM »
I do not think that posts like this is what Martin had in mind as product reviews.
 

I don't mind the posts and I'm sure some folks will find value in them.
« Last Edit: November 09, 2012, 08:28:56 AM by MJLorton »
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iloveelectronics

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #6 on: November 08, 2012, 09:44:42 PM »
MS-8240D

Pros:
1. High resolution at 22000 counts
2. Easy access to batteries and fuses through 2 screws with metal threaded recievers.
3. Big beefy fuses.
4. Uses 4 AA size batteries instead of a 9V.
5. Offers the missing features on the UT61E, namely the Backlight (nice and even too), Max/Min, Auto Power Off and the ability to turn off PC data logging to save battery life.
6. Good accuracy.
7. Lightning fast continuity tester.
8. Fast autoranging (the 8250C is faster though).
9. Built-in RS232 to USB interface conversion with CP2102, optically isolated by a pair of infrared LED and photodiode.

Cons:
1. Mushy range switch.
2. Build quality and design of the housing not as nice as the UT61E. With the UT61E once you put the back and front of the housing together it feels very robust even without the screws. With the 8240D how well you tighten the screws plays an important role. And because there is no metal threading for the housing screws the longevity and robustness really comes into question over time (after you've opened it up a few times).
3. A bit too bulky, especially when comparing to the UT61E.
4. Still no temperature measurement although the chipset has the function available.
5. Only down to 10pF resolution on capacitance measurement. Curiously UT61E does it down to 1pF resolution.
6. Aside from the beefy fuses the input protection looks wimpy. I can only see one spark gap and a tiny surface mounted MOV. The fuse terminals also seem a bit too close to the input jacks, although when closed the plastic case does offer a bit of separation but it's still not completely shielded.
7. Same as the UT61E, it suffers from a very high burden voltage problem for low current measurement, especially on the micro amp range.
8. At least 50% higher in price comparing to the UT61E.

The particular unit I've got has the user manual and software missing, although the supplier claims that they were included. I have tested the PC connectivity with the UltraDMM software though which supports the UT61E, and I can report that it works fine with this MS8240D. Another interesting thing about all 3 of these Mastech meters is that I don't see any aluminium shielding at all on the back or around the cases. I have no idea if the missing software or the lack of the shielding has any thing to do with these being special ordered units and not retail ones.

As it shares the same main chipset with the Uni-T UT61E I tend to compare them a lot with each other. The backlight and the other missing features from the UT61E surely are nice but at a much higher price level I'm not sure I would choose this over the UT61E. The less robust housing and mushy range switch also are a bit of a turn-off for me as well.
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iloveelectronics

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #7 on: November 08, 2012, 10:19:20 PM »
That concluded the mini review of the 3 Mastech meters. I hope some of you would find some value in it.

Now the question as an eBay store owner: do you think any of these meters will sell? Would you buy any of them?
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retiredcaps

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #8 on: November 08, 2012, 11:11:54 PM »
That concluded the mini review of the 3 Mastech meters. I hope some of you would find some value in it.
Hi Frankie,

I think your reviews are great.  They give enough info with good pics that if I'm interested, I can do more research and ask questions.

Quote
Now the question as an eBay store owner: do you think any of these meters will sell? Would you buy any of them?
If I were interested in them, I would certainly support your store/Martin and buy from you.  A lot of it depends on the price.  For example, if they sell for $100, then you are competing against an used Fluke 87 on ebay.

iloveelectronics

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Re: Mastech MS-8233E, MS-8240D and MS-8250C
« Reply #9 on: November 08, 2012, 11:28:40 PM »
I think your reviews are great.  They give enough info with good pics that if I'm interested, I can do more research and ask questions.

Thanks!

Quote
If I were interested in them, I would certainly support your store/Martin and buy from you.  A lot of it depends on the price.  For example, if they sell for $100, then you are competing against an used Fluke 87 on ebay.

Since I don't know eventually what prices I can actually get them for, if I decide to order more, it's hard to give hard figures. I did give some indications in the reviews for some rough price ranges. The 8233E would be a sub-40 dollar meter, 8250C at a similar price as the UT61E (sub-60), and the 8240D I would imagine to be at least $90, likely to be closer to $100. All these prices I'm quoting would have worldwide air mail shipping included.
My eBay store: http://www.99centHobbies.com
Email: franky @ 99centHobbies . com