Help to identify a strange UNI-T ADC chip

[siealex]

Today I found a strange UNI-T multimeter on our local auction. Externally it looks like an ordinary UT-33C (the old 7106 based version, not 33C+).
However:
1. Overload is displayed "OL" with or without the negative sign, not "1", as on a typical 7106.
2. The HOLD switch is a simple pushbutton connected to the chip, not a 6-pin switch with two fixed positions. Hold is activated (and deactivated) by a short pulse, not by a constant level, as on AME7106.
3. Backlight control is built into the chip, the backlight switch is also a simple pushbutton.
4. The LCD display is compatible with 7106 based devices. So this is not e. g. UM7108F.
5. The external circuitry looks typical for an ordinary 7106.
The chip itself looks like a small COB blob without any markings around it on the PCB. What version can this be?

[Martin72]

Hi,

What version can this be?

A picture of the chip/board instead of the complete meter would be more helpful for your question.

[siealex]

I'll take them tomorrow, taking a picture of the board from the chip side requires unsoldering the backlight LED.
Strangely, on an "ordinary" 33C/133C there are TWO backlight LEDs and they are NOT attached to the display frame, so removing the frame is possible without any soldering.

[magic]

7106 was cloned countless times by countless manufacturers all over the world. Whatever it is, it's probably made in China so maybe search for "7106" on LCSC? But UNI-T is large so I suppose that such chip could also be a custom order from them, not available elsewhere.

I'm sure it looks like every other black blob

[siealex]

I'm sure it looks like every other black blob

Yep, a round black blob. Interestingly, the PCB itself has a marking: 33C (CHN). Normal 33C has simply "33C". Can it be a special model for the Chinese market?