Mastech MS5308 LCR Tester member discount

[staxquad]

@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 7x NiMh inboard batteries (max 10v, min 8.55v)


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



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    (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.