sick puppy uni-t ut139c liqid in battery compartment

[kokodin]

Hello there i recently discovered that my favorite work tool uni-t ut139c true rms multimeter has gave out a ghost
the way i discovered it was  even wierder
multimeter was working fine, i taped with it on something to move it, very soft, but it gone blank and after trying to turn it on  was beeping and blinking
after opening battery compartment i discovered that most likely alkaline batteries has leaked. Batteries themeselves might have been there for 3-4 years already so i am amazed it still worked up untill now, but at least one of them spilled the juice all over the battery compartment and probably dameged something inside

i cleaned the thing quite well with ipa, put new batteries in and  it kind of back to life only it now go and show wierd things

volts DC -0.3 - -0.5V
volts AC 0.004 probably fine  but still interesting
mV DC -573.3 mV
mV AC - 0.00
ohms auto range go crazy megaohms shows 0.000 other ranges OL
temperature probe works but shows around 1 to 4 degree celsius too much the lower the temperatore the bigger the error
amps without load shows 0 on all ranges , didn't tested more
nvc worked contantly , now don't detect even close by wires
and a clamp shows -57 amps DC with no clamp

i have no idea which revision of the board is it  but i can find that out probably
i know the case molding was made in 2013 based on the internal stamp but that might be missleading

i don't know what to check or how to clean it better, it doesn't seems to be missing anything or be dirty inside
is it time for a new meter?

[tunk]

Don't know if it makes any difference, but did
you clean the contacts on the rotary switch?

[kokodin]

yes i did, multiple times in fact
i noticed there was some crystalisation buildup on negative battery connector so i desoldered it and cleaned that also along with every area of the board that had the white stuff on it, which wasn't much, mostly around desoldered contact.

board looks clean  but i am not sure is ipa disolves bases or if the crud that is there didn't creadte mini battery with metal on the traces. if yes i can't find it. but it must be after the fuses, taking them out makes no difference

[kokodin]

i think i can close the topic

i got some free time on weekend so i thinkered around the meter some more
since it was alkaline damage  and ipa don't work with that i go a bit crazy road with it and gave it a bath in water with citric acid (after desoldering the screen and beeper)
i don't even know if the solution was strong or weak but it was visably bubbling around any white stuff that reapeared since last clean up, and took it all out in secunds. and i kept it inside for  a bit longer brushing all around.
later i gave it 2 water baths and standard "water damage" ipa cleanup
 after cleanup and drying most of the ranges works normaly exept miliVolts where i still have negative runaway but now around 1mV/s starting from 0 slowing down around negative 30 and it counting 0.1 mV/s from there. who knows, when it get fully dry it may stop doing that
anyway shorting leads gives a stable readout around 0.00mV i say good enough
i don't use miliVolts at work so this might be fine even if it stays like that because this might be even static electricity or something  i didn't clean or dry and does not affect reading accuracy that much