Depending on who you buy from, you will get vastly different prices and
guarantees:
-
At the high end of the range are dealers who sell guaranteed (usually
calibrated) lab grade test equipment at a (substantial) fraction of the new
price. Their web sites are probably most interesting for the information that
they have about particular items, since some of the cut-rate guys only say
something like "HP200CD". Tucker is a good
resource for identifying items and getting a sense of value. It has a large
inventory with pictures and brief descriptions. If you compare to low-price
equipment dealers, you will find that Tucker/3 is usually a
reasonable price, Tucker/5 good and Tucker/10 a steal. However, on eBay at the
moment the market seems so gluttted with used instruments that selling for
Tucker/10 is the norm, and instruments that would have gone for $30 or so a
year ago are getting no bids at all. This is probably due to the downturn in
the electronics industries.
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In the middle are dealers that have a 30day guarantee of operation but no
calibration.
- At the bottom end are dealers who sell stuff "no DOA" or "as is". Many
sellers have a 5 or 10 day "right of return", where you can send it back for a
refund, but are out the shipping costs. eBay sales usually fall in this
category. "no DOA" means "not Dead On Arrival", and doesn't have any clear
legal definition, so it's really between you and the seller. This probably
means that there's no obvious damage, lights came on when powered up, and there
was no smoke. The key question is who pays shipping if when it arrives, you
decide it is "DOA".
I've bought most of my instruments on eBay. If you don't want to spend a lot
of money, and are willing to take the risk of getting something that doesn't
work, eBay is best (see my eBay hints.) Most dealers
now use eBay for selling items with weak demand or that are more popular with
hams and audio buffs than engineers. Because of this an astonishing thing
happened: I bought a Tektronix 7A13 from
Tucker, the premier over-price dealer.
If it's important to get something that works because you don't have the repair
skills, then by all means, buy something that is sold as working. This is a
good approach when starting a home shop because you can't repair anything
without some working instruments. And once you do start servicing instruments,
you'll find you need more instruments...