EEVblog Electronics Community Forum
General => Buy/Sell/Wanted => Topic started by: iloveelectronics on February 02, 2013, 10:18:38 am
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Hello all,
I have a number of brand new Mastech MS5308 LCR Testers in stock at the moment and am offering them for sale to forum members at the discounted price of $170, worldwide registered air parcel shipping (with tracking number) included. Batteries (8 x AA size) will not be included though due to Hong Kong Post's policy.
Another forum member, John, has a wonderful review here:
Mastech MS5308 LCR Tester (https://www.youtube.com/watch?v=9el9mW5woSM#ws)
and I believe Martin (of MJLorton Youtube channel) will be doing another review video as well when the unit I sent him arrives.
WARNING: In his video, John talks about an issue with the power adapter at about 33:25 of the video. Basically the meter will not function correctly using that adapater. In fact, you should NOT be using the power adapter that comes with the package at all, because you could potentially damage the meter!
I have contacted the manufacturer directly and posted their official response in another thread but I'll repost it here:
To summarize:
1. They are aware of the issues through reports from their customers.
2. Besides the incorrect reading on resistance measurement as shown in John's video review, the power adapter could also potentially fry an IC (they didn't mention which one) and stop the meter from switching on.
3. They acknowledge that it's a design flaw in the power adapter that causes excessive ripples, which leads to the above mentioned problems.
4. The meter functions correctly and within specs otherwise (when on battery power).
5. There's no fix at the moment apart from advising their customers against using the power adapter. For customers with a fried IC they will offer a replacement one with instructions and assistance on how to replace it. The power adapter will no longer be packaged with the meter from now on.
6. They will be working on a redesign and modification in the documentation.
7. After that they will modify based on the redesign all the units that still haven't left the factory.
I haven't tested the meter with a better DC 12V power adapter yet but I reckon it will work fine with a proper one. I may try to source some reasonably priced 12V adapters soon, after the Chinese New Year.
If anyone's interested in this meter, please either leave a message here in this thread, or contact me via PM. Thanks!
Cheers,
Franky
P.S. the pictures are taken with my own unit, the ones I'm selling would never be opened up like that :)
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Hi Franky, yes I am in for one. I have been following the other thread and know about the power supply issue, I have no problem building my own linear supply. I was on the fence with this unit but figure it is correctable. I assume you prefer non-ebay, so send me a message to do the paypal thing.
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Hi Franky, I'd like to have one too. Please pm me the details.
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Thanks a lot for all the interest! All PM responded. For those who have sent payment, your LCR meters will be shipped on Monday. Thanks!
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Is this still on? Would love to buy one at that price as well...
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Yes, they are still in stock. Send me a PM with your paypal email address and I'll send you an invoice. Thanks!
Is this still on? Would love to buy one at that price as well...
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Pm sent!
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PM sent, thanks
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I need 2 pcs of MS5308. Do you have it ? Product need to be delivered to UK.
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I need 2 pcs of MS5308. Do you have it ? Product need to be delivered to UK.
I do have the last 2 remaining in stock. If you could send me your paypal email address in a PM I will send you an invoice and reserve them for you. Thanks!
Cheers,
Franky
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PM sent. pls chk ..... :)
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PM sent. pls chk ..... :)
Invoice sent. Please note that I won't be able to ship until Thursday or later, as it is Chinese New Year over here and the post office is closed through Wednesday.
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Thank you everyone for your interest and support. These meters sold out much quicker than I expected! I will be ordering more from Mastech after the holidays but I know pricing on their end has already been adjusted (over their entire range of products) so unfortunately my next batch for sale will be priced higher too :( I will make sure my price stays lower than anywhere else you can find though!
I will likely only have these back in stock in early April. Don't quote me on this but I believe the new ones will be slightly modified because of the power adapter issues, but will NOT come packaged with any power adapter anymore.
If you are still interested in getting one please contact me and I will make sure you get one when they are back in stock.
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how much shipping to italy will cost?
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how much shipping to italy will cost?
Worldwide shipping (with tracking) is already included in the price. However, I'm already out of stock on these. I will likely get some new ones in April but pricing will be adjusted as Mastech has increased their pricing over their entire product range just before Chinese New Year.
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So I got literally the last one at the old price then. I do like it, it is quite big, much bigger than any other meter I have.
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how much shipping to italy will cost?
Worldwide shipping (with tracking) is already included in the price. However, I'm already out of stock on these. I will likely get some new ones in April but pricing will be adjusted as Mastech has increased their pricing over their entire product range just before Chinese New Year.
oooh what a bad news!
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So I got literally the last one at the old price then. I do like it, it is quite big, much bigger than any other meter I have.
No, you didn't. I got 20 of those. Apart from my own and Martin's, you actually got one of first few units I sold.
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I m the one who got the last two ... :D :D :D
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|O
I wish I had waited a month later before buying mine. Paid about $20 bucks more on Ebay.
It is a very good LCR meter, just toss the power supply into the garbage, unless they changed them out with a better one.
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Finished the linear power supply today, and it works. Very simple, an old 12VAC 1VA transformer ( dead clock radio), a 2A bridge rectifier ( out of the box of bits as the first that was small), a used 2200uF 25V capacitor ( checked it on the LCR meter before use, it was passable for capacitance, ESR and loss so in it went) and a 7812 regulator on a small heatsink ( A little overkill as it will never get warm even as the bare TO220 package but the tiny heatsink made it easier to epoxy down) with the negative grounded to mains via a small inductor. Added a 0.22uF class x capacitor to the input and then epoxied the transformer and the components into the recycled plug top case. Made sure there was a lot of clearance along with placing plastic isolation barriers between the mains side and the low voltage side. Wired it up point to point and reused the original cable strain relief for the Mastech power cord ( persuade the old one out then use superglue to hold the new one in) and added a used green LED as a power indicator. All in all about 2 hours work excluding curing time for the epoxy.
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Received my MS5308 today from Franky, and had a short look at the power supply. It's probably the worst one I've ever seen!
It is rated for 12V/1A, but loading it with a 33 ohm resistor (so something like 360mA) created an output with pulses from 7 (low) to 17 (high) volt!
I'm not even going to use it for something else or trying to fix it, what a piece of cr*p...
The meter is fine though, and since we already knew about the power supply there's nothing to complain about.
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I wish I had waited a month later before buying mine. Paid about $20 bucks more on Ebay.
It is a very good LCR meter, just toss the power supply into the garbage, unless they changed them out with a better one.
$20 is el cheapo for a whole extra month of fun & experience. It is just 67 cents a day ;)
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Did I get a dud I thought to myself?
Tested the supplied power adapter and found it was as noisy as alluded to so cut the cord and mated it with a 12V wall wart. Scrounged some batteries (until I could go to the store to purchase fresh primaries), loaded them in and observed 3 bars on the battery indicator of the unit, seems reasonable.
Tried out the unit back and forth with AC and batteries, same result, frustration. The meter in auto LCR just would not settle on the type of component, let alone a proper value for L, C or R. Switching to L, C, or R modes stopped the incessant dancing around from L, to C, to R in auto LCR mode, but still would not settle, or would settle on a completely bogus value.
Not knowing what was going on, I tested the wall wart's voltage and it fluctuated from 12.5V down to 12V depending on the load MS5308 drew. So I tried a CV power supply (12v, 10A, switching), adjusted it to 12.00V and as MS5308 operated, the voltage remained constant, but this time MS5308 operated as you'd expect, homing in on the component mode then the correct value in auto LCR and the individual modes.
Afterwards checked the voltage on the supplied power adapter to see what it was adjusted to, 12.45V.
So for the unit to function properly, it requires fresh primary cells or a constant voltage power supply. The unit is not a dud.
1V/div, 100khz repeat (2 micro sec/div)
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@staxquad: a little warning
Have you seen the other thread started by wavebits? ms-5308-power-supply-issues (https://www.eevblog.com/forum/testgear/ms-5308-power-supply-issues/msg189749/#msg189749/)
That thread indicates that there is a LDO on the inside that is operating right at its maximum input voltage. I have been ultra cautious with my unit. First when I loaded it with fresh alkalines I measured a battery voltage of 12.79 (before inserting all) so I replace 4 batteries with some Nimh rechargeables to bring it back down to 11.75. It has been working fine with full battery indicator. It does hunt a bit with nothing connected to the inputs before settling on 9.2 pF but that is expected. When I build a dedicated bench supply for this thing I am going to set the output to 11.5 volts. I haven't used it that much yet but find it is more fun than expected when I do.
edited: having trouble with the URL thing, think it is fixed now
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(http://)@chickenHeadKnob...Thanks for the heads up. I assumed if the manufacturer supplied a power source at 12.45v and required 8 cells that it ran on ~12v. So much for assumptions.
So the power supply has issues with noise and over voltage, MS5308 has battery voltage issues with 8 cells and MS5308 requires voltage stability.
I tested the unit all the way down to when "batt" showed up on the display for a few seconds before shutdown.
the battery indicator shows:
four bars from 11.43 volts and up;
three bars from 10.38 volts to 11.42 volts;
two bars from 9.37 volts to 10.37 volts;
one bars from 8.34 volts to 9.36 volts;
shutdown at 8.33 volts (idling).
shutdown at 8.35 volts (running with back-light and RS232)
Tested MS5308 at 8.50 volts while using RS232 data logging and the back light on while changing frequencies and it worked fine, with stability, so obviously any higher voltage also did work, not dancing around. No point risking the chips if it works at lower voltages.
Looks like voltage stability makes the meter work correctly, weak batteries and unregulated wall warts are susceptible to voltage dips making the unit dance. So when I had scrounged mixed secondary batteries for the unit, it showed 3 bars (10.38 volts to 11.43 volts) and still danced around, because the cells' discharge wasn't capable to maintain the voltage under load.
Since MS5308 works correctly at 8.50 volts, and works right up to 4 bars starting at 11.43 volts, I'll settle in between on the low side with the CV power supply set to 9.00v and will use 7x NiMH batteries with the 8th battery a dummy, so the voltage will range from 9.94 ~ 9.66 volts (from 1.42v to ~ 1.38v under load), when the batteries are fresh to 8.50 (1.21v) when the batteries are low, or till the meter dances. Will use a CV power supply set to 9.00v until the ordered matched NiMH batteries arrive, then will test my assumptions. NiMH batteries are pretty flat in discharge.
Good thing I didn't buy primary batteries for it and was aware of the power supply issues, and luckily I didn't apply too many volts to the unit while not aware of it's voltage limitations.
(mica and film caps tested nicely at 100kHz)
update 2/26/13
Received my rechargeable batteries, Chinese versions of Sanyo Eneloop XX, minimum 2300mAh, very stable discharge, preferred by photographers in their flash units, cameras, motor drives; flashlights.
Charged them up, 1.40~1.42v; used 7 of them in the MS5308 meter with one dummy battery giving a voltage of around 10V to start (after a couple of hours and some use, it's at 9.81v) and can use until 8.50v when the batteries are at minimum charge at ~ 1.22v each and at the lower limit of the voltage required to operate the meter, using it's 2500mAh (min 2300mAh) capacity, so >100 hours use before recharge required is my estimate.
The resistance is a test standard at .0025 ohms, MS5308 displays either .002 ohms or .003 ohms.
The meter is stable while using all it's capabilities with either batteries (10.00v to 8.50v using it's full capacity) or with a constant voltage supply of 9.00vdc, so I'm set and satisfied with low voltage use.
(The battery level was at one bar when I was using the 9.00vdc power supply)
update 2/27/13
Had one shutdown at 8.50 volts, so upped the lower limit to 8.55 volts.
video tests:
MS5308 test with a Constant Voltage Power Supply adjusted to 8.55V
MS5308 test with a Constant Voltage Power Supply adjusted to 8.55V (https://www.youtube.com/watch?v=673U3lpoL0s#)
MS5308 test with 7x NiMh inboard batteries (max 10v, min 8.55v)
MS5308 test with 7x NiMh inboard batteries (max 10v, min 8.55v) (https://www.youtube.com/watch?v=3f9QSnLBvOI#ws)
Batteries being used, 7x BTONE AA 2500mAh (min 2300mAh) similar to Sanyo Eneloop XX, and one dummy battery to allow 7 batteries to work in an 8 battery holder.
Components under test:
.0025 Ohm test standard resistor;
1mH to 5mH variable inductor;
10 Ohm 1% resistor;
1k Ohm resistor;
1.2uF to 40pF decade capacitor
10 Mohm resistor;
3900pF mica capacitor;
1000uF electrolytic capacitor;
.1uF film capacitor;
.05uF ceramic capacitor;
.001uF polystyrene film capacitor.
update 3/6/13
(Maybe someone can report how well 1.5v alkalines x 7 works, ~10.5 volts down to 8.5 volts?)
Removed the batteries to drain some capacity, 2.5A for 30 minutes on a load, reinserted the batteries at 8.70V to continue testing.
Completed the MS5308 test with 7x NiMh inboard batteries to shutdown at ~ 8.50v
MS5308 test with 7x NiMh inboard batteries to shutdown at ~ 8.50v) (https://www.youtube.com/watch?v=YGGINAXfd4w#ws)
Charging the cells: the smart charger determines how many cells are being charged, determines the charge current and terminates the charging when complete. Charged to 10.19v taking 4hr53m (had set the max to .5A but the charger decided not to go higher than .43A), next day the cells settled to 9.80v or 1.40v/cell.
The smart charger even charges wood ;D (a drilled through the center dowel with copper ends and a wire joining both and soldered, completes the circuit for the 8 battery holder).
update 3/27/13
(Maybe someone can report how well 1.5v alkalines x 7 works, ~10.5 volts down to 8.5 volts?)
Tested that.
8x Alkaline cells ends up @12.993V
7x Alkaline cells plus a dummy cell ends up @ 11.370V
Running with 7 cells, the meter worked as expected
I didn't try the meter with 8 alkaline cells @12.993V.
The dummy cell with either 7 alkaline cells or 7 NiMH cells is the way I will run the meter by battery power.
From a regulated power supply, the voltage will be adjusted 9V.