Products > Test Equipment
Mastech MS5308 LCR meter with ESR measurement - on discount at the moment
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KD0CAC John:
Good to hear some details from them .
Seems to confirm that the issue is with the PS only " excessive ripples " .
Not being into electrical design , just hobby , wouldn't using a filter cap added to the PS solve this ?
Besides just using a good , maybe laptop supply - reduced to the correct voltage ?
SeanB:
Not ripple on the voltage, but too much HF noise riding on top of a mains frequency waveform injected into the power rails. Basically they need a power supply with a grounded secondary side.
nixxon:
It should not be a big deal to find another 12V DC power supply from some old equipment. I will check the output quality first, of course. If it is a linear type, there should not be high frequency noise anyhow.

Even so, I will check out if a .47 uF X2 capacitor I found will reduce the noise from the Mastech power supply...
bingo600:
I have a Mastech meter (from summer 2012) , so i'm prob affected by the problem PSU.

Now i have several 12v wall-wart switchers and also an old 12v ironcore wall-wart.

My question is ...

How close to the 12v do i need to be ?
As in how well regulated/clean does the DC need to be ?

The Iron-core prob puts out 12+ volts ?

Is there a regulator inside the meter ?

Or does the supplied 12v need to be 100% clean , i have some LM340-12 in TO220.
But would like to avoid an "external" box if possible

How many mA does it need to deliver ?

TIA
Bingo.
nixxon:
It draws ~15 mA w/o backlight, according to the review video. With backlight, it was ~30 mV IIRC. EDIT: I don't know the current draw with the backlight on.

I have read that 9 volts is the absolute minimum for the meter to operate.

BTW: The meter can handle a 75 cm drop from a table down onto a ceramic-like tiled floor.  It makes a horrific sound as the unit hits the floor, though.  :palm:
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