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Hi, all. I just purchased a "Tektronix Multiplexer Control Unit",
for the huge sum of $2.25. (I guess no one else was paying
attention, at the time! (Ebay, last night!))

It includes 23 individual S-1 Sampling Heads plugins, which I think I
am somewhat familiar with.

But, it also includes 32 individual "S-3260/Mod 20 Compensator"
plugins. I have NO IDEA what these are, and can't seem to find ANY
information with web searches.

I am hoping to help finance my Tek scope lust, with this windfall. I
know the sampling heads are worth a little something. But I haven't
a clue as to the usefulness of the compensators...

Does anyone know what these are good for? (First good answer gets a
free Compensator plugin, post-paid...!)

Thanks!!

Tom Gootee
tomg@...

Wow, I need to pay more attention to eBay! You got a REAL STEAL on this
stuff, and yes, I know what it is.

The Tek S-3260 is a very large computer controlled system for testing
integrated circuits. It is vintage about 1975 or so. Some of the options
for the S3260 included a 568 scope with 3S6 and 3T6 sampling plugins for
making some very fast risetime measurements on the IC under test. The
S3260 was capable of handling large scale ICs with up to 64 pins in its
largest configuration (they may have even made larger ones than that). Any
way, the 568/3T6/3S6 is only a two channel sampling system so how do you
look at 64 IC pins with only two channels? The answer is that you multiplex
the two channels to all 64 pins. How do you do that without losing all the
fast capability of the sampling system? The answer is that you locate the
sampling heads (S1's in this case) as physically close to the IC pins as you
can and dedicate one S1 to each IC pin and multiplex the S1's to the two 3S6
channels. The multiplexing is done in groups of up to four sampling heads
plugged into a 286 Sampling Head Multiplexer. If your system needs more
than four sampling heads multiplexed, you can multiplex up to four 286's
with one 288, for a total of up to 16 sampling heads. Still not enough
sampling heads? OK, you can slave up to three 287's to one 288, each one
loaded with four 286's, with each of those 286's loaded with up to four
sampling heads, for a grand total of 64 sampling heads multiplexed. All of
this is explained with pictures on page 251 of your 1973 Tektronix Catalog .
. .

The multiplexers (286's, 287's, and 288's) are not particularily valuable
today (except as maybe an addition to my collection!) since they are only
one component of a large S3260 system and you don't have the rest of it,
like the DEC PDP-11 computer, the Tek 1340 Interface Units, and the
necessary software to control it all. The S1's however, are the gold at the
end of this rainbow! The 1989 Tek Catalog lists S1 Sampling Heads available
from Tek new at a cost of $1695 each! (And you got 23 of them for $2.25 . .
. ! ! not to mention the 286's, etc.) Anyway, those same sampling heads
are useful in the 3S2, 7S11, 7S12 and a few other sampling plugins. So, if
those sampling heads actually work, you should be able to get at least 1000
times your money back . . . but you would really need to check them out
first to expect that kind of return. You say you don't know how to check
them out? OK, so I will give you ten times your money right now and I'll
check them out . . . how about that! 8-)

I took a look at the picture of the stuff you bought and I actually counted
55 sampling heads in the picture. You could always complain to the seller
that you thought you were getting everything shown in the picture and you
expect to recieve all 55 sampling heads . . . ! ! (Then you should be able
to get 2000 times your money ! ! )

Surely this detailed explanation is worth one sampling head and not just a
crumby old useless S3260 compensator card, right?

Stan
w7ni@...

tomg@... wrote: