Uni-T UT204A clamp meter 600 A range zero adjustment?

[pOM]

Is there a way to adjust the 600 Amp DC range indication to be at or near zero when there's no wire or nearby field present?  Mine reads 23 ("0023") Amps!

The 40 Amp range has some residual, but it's down around 10 or 20 ma., and not a concern for my use. 

I know I can, and I do, use the "relative" function to zero the meter; however, if I could get the 600 A range residual to be zero, or even just a few Amps, it would be small enough that I wouldn't have to use the relative function every time.

https://www.eevblog.com/forum/testgear/uni-t-ut204-clamp-meter-review-and-tear-down/msg173557/#msg173557 has a link to the schematic (Reply #23) and a list of the variable resistors (Reply #2), but as far as I can tell none of the latter are for zeroing the residual indication on the 600 A range.

The "23" is rock-solid and repeats every time the meter is turned on.  It also adds to the actual current in the positive direction, and subtracts from the current in the negative direction.  I wonder if it's being caused by an errant fixed component rather than a variable control that needs resetting. 

I've opened the case but haven't yet done any close inspection/testing along these lines.

[Fungus]

It might need degaussing.

[pOM]

Thanks.
I had thought of something like that, but then wouldn't it affect the lower current range (40 Amps), at least as much, and perhaps even more? 

Not sure how I could degauss it, in any event.  Ideas?

[Fungus]

Thanks.
I had thought of something like that, but then wouldn't it affect the lower current range (40 Amps), at least as much, and perhaps even more? 

Probably.

Not sure how I could degauss it, in any event.  Ideas?

Wave a magnet near it. See if the offset goes up or down. If it goes up then turn the magnet around. Repeat.

[pOM]

Moving a magnet near the sensing end, and especially within the clamp area, does cause the reading to change, but that's normal.  It's simulating the magnetic field around a wire that's carrying current.

Earlier I linked another thread that had a schematic and range-calibrating controls; however that was wrong.  It's for the UT204, not the UT204A that I have. 

I found https://www.eevblog.com/forum/reviews/uni-t-ut204a-clamp-meter-review-not-the-one-with-the-truerms/msg169667/#msg169667, which is, indeed, about the 204A.  There, others comment about the somewhat high residual offset.  The response is that it's normal.

I guess that's probably it.