DMM Victor 98A+

DSC_4340

This is one of Victors better models (189W looks to be a more advanced model of the same meter).

DSC_4327 DSC_4328

The box for the meter is a brown cardboard box, that is very practical for shipping.

DSC_4329

The box contained the meter, probes, a usb cable, a calibration certificate and a DVD with manual in Chinese and software.
It is possible to download a manual from Victor, but it do not match the meter.

DSC_4336
DSC_4337
DSC_4338

The probe is fairly standard with tip covers and the usual rating of CAT II 1000V without covers and CAT III 1000V / CAV IV 600V with covers.

DSC_4347 DSC_4370

The meter is heavy enough to be standing while turning the range switch or pressing buttons.

DSC_4341

DSC_4342 DSC_4343

DSC_4348

The two black "screws" are used to open the meter, but the sleeve must be removed first.

DSC_4350

DSC_4357

DSC_4352

DSC_4351 DSC_4353

DSC_4354

DSC_4355

DSC_4356

DSC_4335

The calibration certificate is on multiple pages and show how well the meter matches the calibration reference.



Display

DSC_4361

All the segments on the display, as usual not all of them are used.
The display has two secondary displays and a bargraph where it can show maximum range.

DSC_4360

A typical measurement without extra function activated, the bargraph shows that the range is "200".

DSC_4362

Activating max/min and selected average.

DSC_4363

When measuring temperature the secondary display shows sensor value and reference temperature.

DSC_4364

The dBm display

DSC_4365

AC+DC is very nice with both AC and DC voltage displayed.

DSC_4366

Logging mode, the meter will save a reading each second (It will also beep each second).

DSC_4802

Capacitance mode, with no capacitor it shows OL, maybe due to a -0.1nF offset in the range. This prevents using the REL button to eliminate the offset.

Secondary display functions (After / is secondary values):

Functions

DSC_4409

Buttons: MaxMin/Peak/Rel will all select manual range.

Rotary switch:

Input

DSC_4410



Measurements
DMMInputVoltageSweepmVDC

The input resistance in mVDC

DMMschema

Range switch is unreliable and may not always select same range as switch position.
Internal thermocoupler compensation sensor is 10C wrong.
Capacitance has a 100pF offset in the lowest range and REL do not work because meter is in overload.
Min in min/max do not show minimum value.



Computer connection

DSC_4332
DSC_4331

The meter included a USB cable with mini usb connector.

DSC_4333

And a CD with the software on (The software is date 2017)

DSC_4344

The meter has a mini usb connector behind a flap, this is good for environment protection.

1s

It was difficult to install the software, it use Chinese file names and my windows could not handle them. Some renaming later I succeeded in getting it installation and started. It uses NI-VISA software.
First windows was a bit depressing to look at.

2s

Pressing the button with the green letters reset the meter and starts reading data.
I did not get a chart or a table, only current values from meter.

3s

Pressing the Hz button in AC mode shows 3 value, but not the same values as the meters display that only shows two vales.

4s

Peak worked the same way, the screen shows peak max and peak min.

The software is not really usable on my machine (It will probably work better on a Chinese windows)



Tear down

DSC_4803

I had to remove the battery cover, then it was four screws to open the meter.

DSC_4804

The back is fairly hard plastic and looks rather thin.

DSC_4805

DSC_4806

I had to remove 3 more screws to get the circuit board out.

DSC_4807

It looks like the switch assembly can be taken out, but it did not move easily and I let it stay in place (I probably had to remove the screw inside the switch).

DSC_4808

DSC_4809

DSC_4810

DSC_4811

The display assembly is clipped on and could be removed if disconnecting the display cable.

DSC_4812 DSC_4813

DSC_4815

This side has the low volt input protection, i.e. transistor pairs: mVDC, temperature, continuity, diode, ohm, RTD, capacity (T1 & T3), Hz (T8 & T9), capacity (T2 & T4) after a 100kOhm (R34) resistor.
The uA current shunt (R24: 100ohm) is on this side.

The main multimeter chip (U1: HY12P65 5000count). There is two memory chips (D4 & D5: Marked 4256-2GLI) for logging and other stuff. Above these chips is the USB interface on a separate board, it has two optocouplers (U1 & U2: Cosmo:K1010 5000V) and a standard USB interface chip (D1: CP2102)

DSC_4824

The optocoupler is fairly good, but how much safety distance are there? The ticks on the ruler is 1mm apart, this means from the usb track to the ground place is about 2.5mm, this is not very good.

DSC_4820

DSC_4821 DSC_4823

DSC_4822

DSC_4814

The voltage input terminal has 3 paths, one with fairly high input resistor (470kOhm) and two with lower ohms value (2x470ohm), both followed by a PTC (PTC1 & PTC2) and a GDT (VR1 & VR2) to common. There is a unmarked capacitor for AC input and the voltage divider resistor (R28..R31: 4x2.5Mohm).
The mA current shunt (R23: 1ohm) is here, together with the current shunt protection diodes (Z1, ZZ3, Z4, Z5).
The power supply (U3: Marked IF33) and maybe one chip more (D5: Marked CM011B / 5AKG4 / CNQH), this chip could also be some other functions.
The main processor is here (D1: Marked 68ALKZTG4 / 430F5327 / EV K).

DSC_4816

DSC_4817 DSC_4819


DSC_4818

DSC_4826

The display module required two screws and four clips to open.

DSC_4827

It has two LCD drivers (D200 & D201: 2xHT1621B) and a transistor (T200) to control the backlight.

DSC_4828

The backlight can be seen at the back of the circuit board.

DSC_4829

A closer view of the two leds.



Conclusion

The meter has what looks like a decent input protection, but I am not sure the distances are enough and the USB output has rather low creepage distance. The fuses are only for low voltage/current, not for CAT III. I.e. the CAT rating is not correct.
The meter can measure a lot, has good usage of the secondary display, but there are too many issues:


Notes

I did complain on Aliexpress about the capacity fault, but it was ruled to be correct behaviour for the meter (Dealer: Instruments).

How do I review a DMM
More DMM reviews