[sdiy] weird analog multimeter

[Ingo Debus]

Hi all,

ok, many of you use analog multimeters for synth-DIY, so it's not
completely OT....

Recently I bought an analog multimeter (not very expensive, 30 Euro).
When I tried it at home I found that the voltage readings were about 10%
too low, both for AC and DC. For instance, with 10 volts at the input it
read only 9 volts. According to the manual the maximum error should be
3% or 4%. Resistors could be measured fine, after adjusting the zero, of course.

So I took it back to the shop. The error could be reproduced there, at a
230 volts wall outlet. It showed about 200 volts. So the salesperson
gave me another multimeter (same type). I tried it immediately at the
shop at the wall outlet, it showed about 230 volts. Ok, fine, so I went
home again. Tried it again and.... same error as the first multimeter!!
What had happened? Did I inadvertently take back the bad meter again
instead of the good one?

Again back to the shop. The salesperson didn't want to check the meter
again, but said he was "101%" sure that I hadn't took back the old
meter. I am pretty sure that I hadn't done any bad things to the meters.
Since they had no more meters of that type, they gave me the money back.

Then it dawned on me: the meters are packed in cardboard boxes with an
"anti-theft" sticker on it. Before one leaves the shop, these stickers
are deactivated with a strong magnet. Could this have ruined both
meters? The salesperson said they never had any issues with these
magnets. But it could be possible.

Sounds reasonable?

Ingo