(Too_Many_Tools) wrote in
om:

I have an opportunity to buy a TDS420 oscilloscope.

What is your opinion of this scope?

It was a good scope when it was supported by Tek.
Now,YMMV.

Are options and repairs available for it yet?

Repairs or parts from Tektronix,no.It's past the Long Term Product
Support(LTPS) period. They will calibrate it.(done on an automated cal
system.)

Software may not be available from Tek,either.


Where would you buy accessories for it?

Probes are still available from Tek.


TIA

TMT



--
Jim Yanik
jyanik-at-kua.net

(Too_Many_Tools) wrote in
om:

I have an opportunity to buy a TDS420 oscilloscope.

What is your opinion of this scope?

Are options and repairs available for it yet?

Where would you buy accessories for it?

TIA

TMT


One more note;this scope was intended to be repaired by module exchange,but
once past the LTPS period,Tek disposes of the exchange modules and parts
not common to other in-production scopes.Also,Tek did not put component
level schematics or parts lists in the "service manual" sold with the TDS
scopes(ALL models of the TDS scopes,AFAIK).IIRC,there was a complete manual
supplied to the military,but I have no idea how to obtain one,or any part
number for such a manual.It probably would be a T.O.(tech order) number.

It's also calibrated by software that may not be available anymore(from
Tek).

--
Jim Yanik
jyanik-at-kua.net

(Too_Many_Tools) wrote in
om:

Thanks for the information.

That is what I have been to find out also.

So are we saying that TDS series scopes are throw away scopes?

No,just the *OLDER* TDS models that are no longer under Long Term Support
Period(LTPS). TEK(www.tek.com) has a list of what models are still
supported.Originally,theperiod was 9 years after the last catalog
sales,then dropped to 6 years,and it may be variable now,depending on
model.


If so, Tektronix should be ashamed of themselves.

It would seem that the only way to fix this series of scope is to find
a parts machine. It would also seem likely that the parts machine
would have the same problem of a scope needing fixing since power
supplies (especially HV) have a higher likelihood of failing.

The TDS supplies are purchased components;the manufacturers MAY have
schematics,probably not.The power supplies are switchers,probably much
easier to repair than the scope circuitry.The usual stuff;shorted
diodes,bad caps(ESR),etc.


Another question...in the last 10 to 15 years, what digital scope
(manufacturer and model) do you recommend for repairability?

I don't have an answer for this one.
IMO,if you want repairability,buy a new scope and you'll have the warranty
and the support period.



One more note;this scope was intended to be repaired by module
exchange,but once past the LTPS period,Tek disposes of the exchange
modules and parts not common to other in-production scopes.Also,Tek
did not put component level schematics or parts lists in the "service
manual" sold with the TDS scopes(ALL models of the TDS
scopes,AFAIK).IIRC,there was a complete manual supplied to the
military,but I have no idea how to obtain one,or any part number for
such a manual.It probably would be a T.O.(tech order) number.

It's also calibrated by software that may not be available
anymore(from Tek).




--
Jim Yanik
jyanik-at-kua.net

I bought an TDS620 2/3 weaks ago on a public auction. I am very pleased
with it. Manuals you can find at tektronix.com . Repair parts...very
difficult..but if you keep the machine in good condition, the
opportunity of malfunctioning is minimal. Buying extra probes; I
recommend Ebay (United stated..but an second hand good TEK probe will
cost you at least 80 euro)

When you buy it let show him the start up screen !! A picture with al
tests passed is important. Sometimes with TDS500/600/700 they don't
pass the aquisition test because somebody ended too soon the probe
calibration function (cost about 20 minutes)...once I thought I killed
mij scope with this action, because I aborted the procedure, bute with
an new calibration procedure on the scope everything worked fine...

For dutch people:
ALs hij 'm maar 3 weken in zijn bezit heeft , 1 probe en waarcshijnlijk
missende kap voor het front..dan weet ik waarschijnlijk wat hij ervoor
op de veiling heeft betaald...moet je me ff mailen...

groetjes
koen


Too_Many_Tools wrote:
I have an opportunity to buy a TDS420 oscilloscope.

What is your opinion of this scope?

Are options and repairs available for it yet?

Where would you buy accessories for it?

TIA

TMT

koen verstappen wrote in
:

I bought an TDS620 2/3 weaks ago on a public auction. I am very pleased
with it. Manuals you can find at tektronix.com .

Do the TDS manuals contain component-level schematics?

Or just block diagrams,the "troubleshooting algorithm",and exchange module
part numbers?


--
Jim Yanik
jyanik-at-kua.net

(Too_Many_Tools) wrote in
om:

Jim,

I appreciate your comments but a scope is either repairable or it is
not.

Product loyalty works both ways. When the user is held to the mercy of
when the manufacturer will decide whether or not it is convenient for
them to have parts on hand and schematics avaiable, then that user
should shop with price being the number one consideration. When a
product becomes a commodity item as scopes are becoming, brand name
means nothing if the product is to be purchased with a throwaway
mentality in mind. If I am forced to buy a scope that has an effective
lifetime of several years, then I will shop for price first and
performance second.

The time a company will carry parts is driven by the quantity of their
last time buy on components for that product. If they considered
reliability important (and customer loyalty), they would make
provisions for long time support through third party sources.

As for TDS power supplies, when the schematics themselves are not even
available then that tells you how little Tektronix cares about its
customer base. Something I will keep in mind when I plan for our
company's next bench upgrade.

IMO, TEK does not consider hobbyists to be part of their customer base.
(and I'm not arguing in support of TEK;IMO,they SHOULD include schematics
and circuit descriptions in their service manuals.)

Supplying custom parts,like any other industry,is a choice that they make
on their own,though.






--
Jim Yanik
jyanik-at-kua.net

Too_Many_Tools wrote:
Hi Jim,

As I said before, I do appreciate your comments.

I agree with you on this. If any company does not want to carry parts,
that it is their right but not to provide the intellectual property
(schematics, part parameters, calibration procedures, etc.) to allow
long term support is in my opinion inexcusable and is done for only
one reason...to force the marketplace to buy new product. If my
experience is any indication, the majority of old scopes are still in
the inventory of companies. It is very common to see 20 to 30 year old
scopes still in use today in a range of industries. While it is their
right to attempt to manipulate the market, it is also the customer's
right to buy from whoever provides the best value. For my money, that
includes long term reliability and maintainability.

Again, I am interested in hearing from anyone who has recommendations
for digital scopes that have demonstrated a good track record of
maintainability and repairability. Also, any other place I should post
this question?

TIA

TMT



Jim Yanik wrote in message ...

(Too_Many_Tools) wrote in
.com:


Jim,

I appreciate your comments but a scope is either repairable or it is
not.

Product loyalty works both ways. When the user is held to the mercy of
when the manufacturer will decide whether or not it is convenient for
them to have parts on hand and schematics avaiable, then that user
should shop with price being the number one consideration. When a
product becomes a commodity item as scopes are becoming, brand name
means nothing if the product is to be purchased with a throwaway
mentality in mind. If I am forced to buy a scope that has an effective
lifetime of several years, then I will shop for price first and
performance second.

The time a company will carry parts is driven by the quantity of their
last time buy on components for that product. If they considered
reliability important (and customer loyalty), they would make
provisions for long time support through third party sources.

As for TDS power supplies, when the schematics themselves are not even
available then that tells you how little Tektronix cares about its
customer base. Something I will keep in mind when I plan for our
company's next bench upgrade.

Back when the world was controlled by engineers, life was good.
When the bean counters took over Tektronix, they had only one goal.
Make money. Old reliable scopes do not make money. Only shiny new
scopes that need to be replaced regularly make money.

Go find a schematic for that shiny TFT flat panel display you're sitting
in front of.
Go find a schematic for the computer in that shiny new SUV in your driveway.
Go find a schematic for that cable tv box that entertains you.

It's not like Tektronix is the only bad guy on the block. You're just
spoiled 'cause it usta be better.

It's better for everybody...except maybe you and me...to throw away the
broken one and get a new one. Welcome to the 21st century.
mike




--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

(TekMan) wrote in
om:

Jim Yanik wrote in message
...
koen verstappen wrote in
:

I bought an TDS620 2/3 weaks ago on a public auction. I am very
pleased with it. Manuals you can find at tektronix.com .

Do the TDS manuals contain component-level schematics?

Or just block diagrams,the "troubleshooting algorithm",and exchange
module part numbers?


Hi Jim,

even the tds6xx manuals have NO component-level schematics.

Just what you described: block diagrams,the "troubleshooting
algorithm",and exchange module part numbers.

I had a a pwr supply failure in a tds620a AFAIR, and tracked down the
circuit by handmade drawing myself. Consumes a lot of time, but was
the only way to rescue the scope for a university project.

I still did not find the military source of the schematics (component
level) of the tds scopes Jim mentioned some time ago. So if anyone has
some information for component level schematics for the tds
2xx/3xx/4xx/5xx/6xx/7xx series scopes: Pls. make a contribution to the
newsgroup.

Andreas


I was wondering because TEK is now selling TDS3000 series scopes,and
probably even newer models.
I just wondered if those "service" manuals contained component-level
schematics.

--
Jim Yanik
jyanik-at-kua.net

(Jerry Greenberg) wrote in
om:

I bought the manual for a TDS 420 since I own one that I bought new.
The manual cost me $160 at the time. The main details only cover the
calibration, using some dedicated calibration equipment, calibration
interface, and the software. Even the software is optional along with
all the specialized test gear.

The manual was a complete waste of money for anyone who is not a
Tektronix authorised service center with the proper Tektronix
instrumentation setup for doing the maintenance on that model series.

The complete scope is serviced at the modular level only. When a
module is replaced, it must be calibrated to match, or the specs will
be out.

The bottom line is that if this scope goes defective on you, if you
are not equiped to deal with it, Tektronix is the only one that can
service it for you. The only thing an indepedent technician can do is
to change an obvious non critical component, if it is determined to be
defective.

As for the performance of this scope, it is very good. I have done a
lot of work with it, and it has helped me resolve a lot of problems. I
compared it to the older 465 series, and it is much ahead in its
performance for many aspects. Being digital, it has its advantages.



Jerry Greenberg
===============




This is why I'm reluctant to recommend a used TDS scope to hobbyists or
small businesses,because it probably is past the LTPS period and no longer
supported by TEK,that being WHY the scope is on the used market.
TEK wanted to "wash it's hands" of it's older products quicker than the
venerable 400 series(extended from 9 years LTPS to 12!).


(LTPS= long term product support)


The sad thing is that TEK was sending the "obsolete" exchange assemblies to
RAMS(Recycling and Material Salvage,or *scrap*) instead of selling them to
a 3rd party service like Verizon,to continue support for their older
products.
That could have changed since I left TEK,though I doubt it.
--
Jim Yanik
jyanik-at-kua.net