The 7633 is a fine piece as long as it is working. If you live in a
humid area, try to either keep it working in an airconditioned or
dehumidified area, or use it frequently to keep the HV section from
getting too damp. Also, keep that area clean inside. I killed my
first one and it was not repairable, so if you need parts I may still
have the carcass out in the shed unless I unloaded it at a hamfest
for parts already. One thing I like about vintage old Tek scopes is
that they hardly drift, compared to what old HP scopes did. I am
talking solid state here, not the big tube scopes. They were in a
different league.
Since killing my 7633, I now have a 7623 which is slightly less
capable for storage and a 7603, as I mentioned before. I use the 7603
with Tek S/A plug-ins, as it has a bigger/nicer screen that the
plastic dB graticle cards fit, and you don't need the analog storage
if you are using one of the better S/A units that had digital
storage, like the 7L14 instead of 7L12, and the 7L18 and 7L5. I use
the -5 and -14 in my shop at home. Last week i hauled 7L14 in my 7603
mainframe out to a local AM radio station to help realign their STL
(950 MHz) from their studio. What a monster to move, but it really
worked well. I could easily see their signal (6 watts, other side of
a ridge a few miles distant) from a yagi on the tower, and it was in
the prescence of CDMA cellular transmitters on the same tower at 850
MHz range. They were booming in, so I was worried about damaging the
front end of the S/A, but it survived and picked out the -70 dBm
signal while these big carriers were just 100 Mhz or less away -
without using a bandpass or notch filter. By the way, don't buy a
7L12 S/A plug-in as you will be disappointed, as it has poor phase
lock, 300 Hz min resolution BW, and you need analog storage screen to
really make use of it. I sold my after I got it at an auction,
realizing that digital storage is the only way to go for useful
spectrum analysis where you need to move markers, study the trace for
a while, and compare tuning (before and after adjustments).
My 7623 is used with the 7B53A horizontal and 7A26 veritcal plug ins.
You don't need faster plug ins as the mainframe (deflection
bandwidth) for 7623 or 7633 will limit your vertical response to 100
MHz. With their P6106 10 x fast probe, you could get 95 MHz freq
response if you had the 7A26 and 70 MHz with the 7A18. For timebase,
the 7B53A dual/delayed sweep plug in is the only way to go with these
scopes.
I still use the analog storage on that 7623 scope, but it takes some
care to remember how to make it work well. You have all those strange
options, and you can really make an ugly trace if you don't practice
setting it up. I used it a lot a year ago testing the built-in flash
on digital cameras (the red eye and autofocus are preflash before the
main flash). I needed to modify some slave units so that the slave
flash would only respond to the main and not the preflash. The 7623
did admirable job, although i have to admit to being spoiled having
access to TDS scopes at work now - we got rid of nearly all of the
analog scopes except for 2467. Last year at work I bought and
installed TDS3034B scopes in rack mount in all of the 200 MHz RF
system racks, to be able to track changes in the waveforms as well as
send them over ethernet to my computer in the office. I can now
detect minor changes in cathode current for big 3 MW triodes in
operation, and know when we will have to change tubes, by using the
stored waveforms compared to active trace.
I have seen the old 7D20 digitizing plug-in used at work, and in my
estimation it was a POS. It is so old that the technology was very
primitive for what you have to haul around. The 7D20 would do 40 MS/s
with 1K record length. If i were going for a DSO, I would look hard
at the Tek TDS 2000 or TDS 3000 series of lunchbox scopes. They are
quite incredible what they can do, up to 500 MHz (2 Gs/S). When I
ever find one of those cheap, I will be done with my 7623 scope
altogether and only keep the 7603 with the S/A plug-ins.
If you can find one working, the 7A13 differential comparator
vertical plug-in is real handy. It allows you to dial in a huge DC
offset voltage, and continue to measure low DC changes, all DC
coupled. Also, it has a calibrated read out of this offset. It also
can be used as a differential set of probes and have the offset
function working. You could look at the ripple voltage across a 50 mV
shunt, for example, while in the presence of 400 VDC - if your probe
tips were rated for it. It has a 20,000:1 Common mode rejection ratio.
Good luck, those were great scopes, if you can keep them going. There
are much better ones now, but I believe that those mainframe versions
were more versatile and reliable than the venerable 454, 465, 466,
468 'portables'.
>Message: 9
>Date: Sat, 25 Mar 2006 23:35:39 -0500
>From: "Will Matney" <craxd1@verizon.net>
>Subject: [Amps] Tek Scope
>To: amps@contesting.com
>Message-ID: <200603252335390140.07F52B01@outgoing.verizon.net>
>Content-Type: text/plain; charset=ISO-8859-1
>
>All,
>
>I finally broke down and bought a Tek 7633 ( 100 MHz DSO ) with the
>plug-ins. I bought a 200 Mhz dual trace vertical amp plug-in to
>replace one 80 MHz one that's in it. I'm wondering if any have used
>the digital plug-in which makes it a digital scope? This is the
>plug-in that takes up all three bays, and is a one plug-in deal. I
>primarly bought it with the intention of buying a spectrum analyzer
>and tracking generator plugin later on. Now though, I'm wondering
>about the digital plug-in. The plugins in it are a delayed time
>base, and two dual trace vertical plugins, both 80 MHz. The one
>vertical was damaged, mostly a couple of knobs so I bought a 200 MHz
>to get the full use out of the scope. It will still have the one 80
>MHz in it which is good. Any comments on the 7633 scope would be
>appreciated.
>
>Best,
>
>Will
>
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