DIYbanter - Advice on buying a tektronix TDS 544A scope

Advice on buying a tektronix TDS 544A scope

(TekMan) wrote in
om:

Jim Yanik wrote in message
...
(Kooner) wrote in
om:

I know someone that is selling a TDS 544A for $3000. No warranty is
offered and Tektronix will not repair if it fails because it is too
old. The seller will let me try it out first for a week before
making a decision. If the scope checks out, would anyone advise me
to grab it or spend a few bucks more and buy something new with a
warranty. For example, a TDS 3014B is $4600 new with a 3 year
warranty.

Thanks,

Kooner

Well,TEK did not put component level schematics in their 'service'
manuals.Now,it's possible that the US military bought some,and they
would have TO's(tech orders) with more complete servicing data.
Also,calibrating one of these is not easy,they were done on automated
test stands by TEK.You need a PC to load cal constants into the
TDS,and the software to do the cal.

Well, that's a difficulty wit hall tds3xx and tds5xx: The service
manual is downloadable, but it's on a module replace basis.
There are no detailed schematics around, AFAIK.

It's been my understanding that -certain- TDS models that were purchased by
the US Navy were required to have complete service manuals,including
component-level schematics.What those models were/are,I do not know.
But those manuals may be available from some military source.

So if scope fails, you either need a junker scope to fix it OR you
have to "track down on component level" by yourself. This works quite
satisfactorily for the pwr supply (a switch mode bought from Zytek
Inc.) or the monitor unit.

But you get lost for the main assemblies: a lot of smd, so extremely
hard to repair.

just my 2 cts.

hth,
Andreas

--
Jim Yanik
jyanik-at-kua.net