Used Analog vs New Digital Scope

[Cyber Vagrant]

At my local surplus shop I've found a tek 2465 apparently in good
condition for about $700 also a 7704A for $135 with 2 7A13s and a 7B85
$75 each. I have read good and bad about these. My main concern is
if I should just buy a new Digital PC card scope for $500. Money is a
secondary issue here, I just want something usefull that will last a
while. Opinions anyone?

 

[R. D. Davis]

secondary issue here, I just want something usefull that will last a
while. Opinions anyone?

For durability, Tektronix 500 series can't be beat. Beautiful sharp
display as well, which makes the displays on many newer 'scopes appear
pitiful.

 

[Walter Harley]

At my local surplus shop I've found a tek 2465 apparently in good
condition for about $700 also a 7704A for $135 with 2 7A13s and a 7B85
$75 each. I have read good and bad about these. My main concern is
if I should just buy a new Digital PC card scope for $500. Money is a
secondary issue here, I just want something usefull that will last a
while. Opinions anyone?

I've got a used Tek 2465A. Best scope I've owned or used. Can't imagine a
PC-based scope coming close. So much of the functionality has to do with
having really good analog design - you can't make up for it with software.

 

[Cyber Vagrant]

For durability, Tektronix 500 series can't be beat. Beautiful sharp

display as well, which makes the displays on many newer 'scopes appear
pitiful.

I looked to avail for a 585A. Although there were some 435, 453,
5440, 465b 100Mhz, and one Gould 1425 20Mhz apparently in good
condition. At the moment all I need to do is audio work. In the
future I'm planning to building some switched power supplies so I
might need a faily fast one then.

 

[Jim Yanik]

[email protected] (Cyber Vagrant) wrote in

At my local surplus shop I've found a tek 2465 apparently in good
condition for about $700 also a 7704A for $135 with 2 7A13s and a 7B85
$75 each. I have read good and bad about these. My main concern is
if I should just buy a new Digital PC card scope for $500. Money is a
secondary issue here, I just want something usefull that will last a
while. Opinions anyone?

2465 was the best analog scope TEK ever made. BUT,the horizontal output IC
was prone to fail,and there are no replacements available.
$700 is not a bad price for one.

7704A is an older scope,but still a good one.However it uses TEK-made ICs
which are no longer available except from parts scopes.CRT should be
bright,in focus,and not dim as you increase the intensity control.
7A13 is a good plug-in(PI),but two is not necessary,a 7A26 is a better gen-
purpose choice.7B85 is a good Horiz PI.Prices seem OK.

Both of these scopes are better than a PC scope card.If you misconnect a
scope lead with a PC card,you can blow your PC.If you want or need a
digital scope,get a TDS200 series,or the newer model(TDS2000?)

I would not even consider the old 500 series,unless you need the heat from
the tubes to warm your shop,and someone gives you the scope for free.

 

[DaveC]

I've got a used Tek 2465A. Best scope I've owned or used. Can't imagine a
PC-based scope coming close. So much of the functionality has to do with
having really good analog design - you can't make up for it with software.

If you decide on the 2465, know that they are a ticking time bomb (I think
the 244x series is also effected). The custom IC U400 (I think it is) in the
vertical circuit is the first thing to go, and Tektronix is no longer
repairing this. Somebody on the 'net advertises replacing this IC for
$500-plus.

I have a 2465 and it is great, but I know when that IC goes...

Good luck,

 

[R. D. Davis]

I looked to avail for a 585A. Although there were some 435, 453,

That's a nice 'scope. Not too long ago, I spotted one with a note on
it that read "free," so, I grabbed it. No, it's not for sale.
Good luck finding one; they do turn up here and there, when you least
expect them to.

5440, 465b 100Mhz, and one Gould 1425 20Mhz apparently in good
condition. At the moment all I need to do is audio work. In the
future I'm planning to building some switched power supplies so I
might need a faily fast one then.

One thing that I forgot to mention, beware of the HP 17xx series
'scopes. Almost 20 years ago, I picked up a 1707B for US$5 at a
college surplus sale; it worked great for several years, then, one
night I made the mistake of leaving it on overnight. Apparently the
HV transformer overheated, and burned out. It took a long time to
find a replacement. Actually, I didn't find a replacement HV PSU
module for this 'scope until this past year!

BTW, does anyone reading this know which leads to the HV module
connect where? Alas, in the course of quite a few years, I lost my
notes from when I disassembled that part of the 'scope. Now, I don't
know how to connect the new module to the 'scope. IIRC, all of the
17xx scopes use the same HV module, so, if anyone reading this has one
and can kindly take a quick peek inside theirs...

 

[mike]

At my local surplus shop I've found a tek 2465 apparently in good
condition for about $700 also a 7704A for $135 with 2 7A13s and a 7B85
$75 each. I have read good and bad about these. My main concern is
if I should just buy a new Digital PC card scope for $500. Money is a
secondary issue here, I just want something usefull that will last a
while. Opinions anyone?

If you're designing power supplies, I'd avoid a PC scope. A slip of the
probe and you can smoke the scope and the PC.
Having a scope in your PC sounds like a good idea IFF you need to
manipulate the data after acquisition. For most other uses, it's a PITA.

If you've not used a digital scope, find someone who has one and play
with it before you buy. I found my Tek TDS540 to be extremely useful
when the event doesn't happen often. Like if you want to watch the
transformer saturate just before the FET explodes. For most other uses,
I find it extremely annoying. I often turn on the analog scope to see
what's happening so I'll be able to set up the digital scope for the
capture I want. Memory depth is critical. It takes a LOT of memory
to be able to view two adjacent pulses at a 25 KHz rep rate...that
funny-lookin' trapezoid doesn't give you much information.

The 2465 has an excellent reputation as an alalog scope.
I have one for sale here:
http://nm7u.tripod.com/homepage/te.html
There's also a discussion of the IC reliability and why you
might want to be concerned about the serial number of the unit you buy.

mike



--
Bunch of stuff For Sale and Wanted at the link below.
laptops and parts Test Equipment
Honda CB-125S
TEK Sampling Sweep Plugin and RM564
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[Walter Harley]

If you decide on the 2465, know that they are a ticking time bomb

Yeah, but what isn't? You could buy a brand new TDS2000, and it's a ticking
time bomb too, because when it breaks the only way to fix it is to replace
the innards, which probably costs more than buying a new used 2465.

We're all gonna die sooner or later; doesn't mean we're worthless

 

[Jim Yanik]

Yeah, but what isn't? You could buy a brand new TDS2000, and it's a
ticking time bomb too, because when it breaks the only way to fix it
is to replace the innards, which probably costs more than buying a new
used 2465.

And once the scope is past the Long Term Product Support period,TEK will no
longer have parts or assemblies for the scope,any of the TDS models.And
they don't come with component-level schematics in the "service"
manuals,either,unless TEK has changed that policy recently.
TDS scopes are intended for module-exchange service only.(unless policy has
changed)

 

[Jim Yanik]

If you decide on the 2465, know that they are a ticking time bomb (I
think the 244x series is also effected). The custom IC U400 (I think
it is) in the vertical circuit

No,it's the Horizontal output IC that has a high failure rate.

is the first thing to go, and Tektronix

 

[Cyber Vagrant]

For durability, Tektronix 500 series can't be beat. Beautiful sharp

display as well, which makes the displays on many newer 'scopes appear
pitiful.

I read good things about the displays, although I read that cleaning
the cams that do some kind a switching is a delicate operation that
has to be periodically done.

 

[Jim Yanik]

[email protected] (Cyber Vagrant) wrote in

I read good things about the displays, although I read that cleaning
the cams that do some kind a switching is a delicate operation that
has to be periodically done.

The cam switches are used on later,solid-state scopes like the 465,475 and
7000 series plug-ins,not the 500 tube-type scopes.They used ordinary wafer
switches,with silver-plated contacts.

The 500 series CRTs are at end-of-life status,a gamble that they'll be
useable for any length of time.The switches will be wearing out,too.

 

[Watson A.Name - Watt Sun, Dark Remover]

If you decide on the 2465, know that they are a ticking time bomb (I think
the 244x series is also effected). The custom IC U400 (I think it is) in the
vertical circuit is the first thing to go, and Tektronix is no longer
repairing this. Somebody on the 'net advertises replacing this IC for
$500-plus.

I have a 2465 and it is great, but I know when that IC goes...

Why not put a heatsink on the chip now to prevent or delay it from
dying in the future?

Good luck,

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[Watson A.Name - Watt Sun, Dark Remover]

[email protected] (Cyber Vagrant) wrote in


2465 was the best analog scope TEK ever made. BUT,the horizontal output IC
was prone to fail,and there are no replacements available.
$700 is not a bad price for one.

7704A is an older scope,but still a good one.However it uses TEK-made ICs
which are no longer available except from parts scopes.CRT should be
bright,in focus,and not dim as you increase the intensity control.
7A13 is a good plug-in(PI),but two is not necessary,a 7A26 is a better gen-
purpose choice.7B85 is a good Horiz PI.Prices seem OK.

Both of these scopes are better than a PC scope card.If you misconnect a
scope lead with a PC card,you can blow your PC.If you want or need a
digital scope,get a TDS200 series,or the newer model(TDS2000?)

I would not even consider the old 500 series,unless you need the heat from
the tubes to warm your shop,and someone gives you the scope for free.

I agree 100%. The 541s and their ilk are fine scopes, but they're a
waste of power; and the knobs take so much force to turn that if you
use it a lot, you'll get callouses on your fingers, or blisters.



--
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###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Walter Harley]

Why not put a heatsink on the chip now to prevent or delay it from
dying in the future?

Do we actually know that the failure is heat-related? I know a couple of
people have suggested doing this, but I don't think I've ever heard why
those chips fail in the first place.

 

[Jim Yanik]

"Watson A.Name - Watt Sun, Dark Remover" <[email protected]>
wrote in message > > I have a 2465 and it is great, but I know when
that IC goes...

Do we actually know that the failure is heat-related? I know a couple
of people have suggested doing this, but I don't think I've ever heard
why those chips fail in the first place.

At TEK we were never told of any specific failure mode,just that the ICs
were first in short-supply,then "internal use only",then not
available;supply depleted.

ISTR it was a bad production run,and the high failure rate was not known
until the ICO/Hybrid manufacturing unit was sold to Maxim and no changes
were able to be made.

But a HS would not do any harm.
(as long as it does NOT contact the cabinet.)

 

[Watson A.Name - Watt Sun, Dark Remover]

Do we actually know that the failure is heat-related? I know a couple of
people have suggested doing this, but I don't think I've ever heard why
those chips fail in the first place.

Well, my thinking is that the cooler the chip, the slower the
degradation from whatever reason. So if you cool the chip ten deg C,
it should last twice as long since the chemical activity doubles with
every ten deg C.

But then I have no idea what's causing the problem. It may have
nothing to do with chemical activity.

--
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###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Walter Harley]

But then I have no idea what's causing the problem. It may have
nothing to do with chemical activity.

Fer instance, maybe the vibrations eventually break the little tiny wires in
there.

I think I'll put a heat sink on mine...

 

[John Miles]

The 2465 has an excellent reputation as an alalog scope.
I have one for sale here:
http://nm7u.tripod.com/homepage/te.html
There's also a discussion of the IC reliability and why you
might want to be concerned about the serial number of the unit you buy.

Interestingly, although your page claims that the 155-0241-02 variation
of U800 is more durable than previous ones (presumably 155-0241-01), a
Google News search shows about the same number of posts from users
asking about both part numbers. I wonder if the production quantities
were similar?

From what I can tell based on the service manual, this chip really isn't
anything all that special. It looks like an ordinary RPTV video driver
chip could replace it, if you made provision for the variable-gain
feature needed for the X10 magnification feature. There is plenty of
room under the motherboard for an aftermarket kludge^h^h^h^h^h^h
assembly, if anyone were inclined to develop one.

I just sold a 2467 on eBay with the -01 part number with 27,000 hours on
it, still going strong. My own 2467 has over 12,000 hours on a -02
part. So they definitely don't ALL die an early death.

-- jm