"TJ Hertz" wrote ...
When I said "I've got a Japanese Akai S1000 sampler",
I actually meant "I'm selling a Japanese Akai S1000 sampler
for someone else". As a result, I didn't know much about
the unit and its condition.

But I asked the owner what she used to do with regards to
power supply and she gave me the transformer that she had
been running it off for the past 7 years or so. Surprise surprise
- it's a 240V to 115V transformer, and she said the Akai
always worked fine despite being labelled 100V. In other
words, she'd been using an incorrect transformer for years,
but it worked anyway.

Generously-designed equipment can likely take a 15% over-
voltage although it may run warmer (and may reduce its expected
lifespan.) But lots of modern equipment is designed on the very
edge of acceptable ranges, so I wouldn't try it as a rule.

A buyer emailed me today from eBay asking if the screen was
still bright or if it had gone dim with age, so I plugged in the
sampler using aforementioned 115V transformer and promptly
got an electric shock from an area on the sampler's case where
a bit of the paint had been scratched off, leaving bare metal. It
is worth bearing in mind that I was barefoot and standing on a
concrete garage floor, but nevertheless, this shouldn't happen.
I plugged it in again and the same thing happened. However,
when turned on, the sampler worked fine - it just gave me a
shock whenever I touched the case (a sizeable electric shock,
not like static). The owner said that she'd never experienced
this before despite using the sampler with the same transformer
on a UK mains supply.

PLEASE DON'T do that experiment again. We would miss you
if you electrocuted yourself! Seriously! There are SAFE ways
of testing for this that don't put your life or limb at risk.

One thing I noticed about the unit was that it used a 2-pin power
lead with apparently no earth. As in, the socket on the machine
only had 2 pins, so there was no option to use an earthed cable
(even though the transformer had earthed sockets). What's the
deal with this? Can anything be done? Obviously I can't sell a unit
on eBay in Very Good Condition if it shocks you when you plug
it in, even if it works fine otherwise.
Is my only option to sell it as-seen with a buyer warning?

Now that you know about it, and especially now that you have
revealed it in public, you really have no ethical choice but to
disclose it to any potential buyer. If somebody bought it and
electrocuted themselves full disclosure would be your minimum
defense.

If it were me, I would be tempted to fit an IEC power connector
on it (like the kind used for computers), with the green-wire
ground securely bonded to the metal chassis. But mains wiring
is not a project for amateurs. I would think that most consumer
equipment service shops ("TV Repair", etc.) would be equipped
for and experienced with testing and fixing this kind of problem.

Ironically, it may be working just as it was designed back
when it was first sold. But you can't get away without telling
bidders about the hazard today IMHO.