EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: jmm418 on August 29, 2023, 07:36:26 am
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Hi
I just Bought a Craftsman 82289 scope meter for $50
it seems to be off when testing capacitors for example a 2.2uf is reading 1.5 i have another cheap meter that reads 2.2 when testing the same cap.
The AC & DC voltage reading is accurate
so i was thinking maybe there is a way to adjust it with a pot that's inside
I have done some research on it the meter seems to be made by extech and there is also a VOLTCRAFT version of it model GDM 704 & Extech 381265 they look the same as the craftsman
someone had taken the volt craft one apart there are a lot of pots inside i wouldn't know which one to adjust without messing it up maybe someone else would know or maybe it's best just to leave well enough alone
https://www-elektroda-pl.translate.goog/rtvforum/topic1678487.html?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp&_x_tr_hist=true
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Are you using the same test leads with both meters? Some of the difference might be there, at least.
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Hi
yes i tried the same leads in both meters but it did not make a difference.
maybe that's just the way the meter is made. or maybe it drifted i think it's almost 20yrs old
if i had the same one to compare it to then i would know.
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I just picked up a Craftsman 82289 miniscope as well (don't ask me why). You got a better deal than I did.
According to the silkscreen the meter is a rebrand of the WENS33N. Amazingly it turns out there's a page dedicated to the WENS33N (in Japanese):
- https://hirokun.jp/av/wens_33n.html
- google translated: https://hirokun-jp.translate.goog/av/wens_33n.html?_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp
The person who wrote that info page also posted calibration instructions with schematics:
- https://hirokun.jp/av/wens_33n_sch.pdf
So you might be in luck as far as getting the capacitance adjusted. Please post details on how it goes!
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Thanks for posting that. Now I just need to figure out how to get it apart.
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it was kind of a pain to get apart at first
the 4 screws in the back where the copper shield is do not need to come out
and the white dial i thought was missing metal contact and one fell out but it's double sided and the top pcb has a smaller contact area so i hope & think it's fine.
all i really had to do to get it apart was pry with a plastic pry panel tool and it disconnects from the f1-4 buttons on the front cover.
adjusting the pot made more of a difference on higher rating caps than lower ones for example 10uf reads about 8