Date   

Re: 80E02 80E03 Sample Module Repair

Mark Kahrs
 

These are definitely a return to Tek kind of item, much like the SD heads.
In fact, you might notice a remarkable resemblance between the two heads!
Unless you are lucky, the sampler is a mite toasted... The heads are very
sensitive to static.

Can I presume you've done all the tests in the user manual?

On Sat, Feb 22, 2020 at 12:02 PM dalek <@dalek> wrote:

Hi. Has anyone had any success repairing these modules? I could find
little to no information regarding the servicing of them.
Richard




Re: Repairing my Tektronix 454 oscilloscope need some advice

 

Hi Ed,

Any discussion, information about HV testing of components should be welcomed by us owners of tube oscilloscopes, and as valuable information in general. The ability to have a variable source of HV and a means (well protected) to detect leakage current should be within our test capabilities. I designed a 100 KV supply with a 29 stage ladder to power a minitron tube, and I survived any electrocution to be able to tell about.

Regards,
Ernesto


Re: Weird 466 horizontal glitch-- be aware

Jim Ford
 

D'oh!  (forehead slap)Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Brad Thompson <brad.thompsonaa1ip@...> Date: 2/22/20 5:07 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Weird 466 horizontal glitch-- be aware Ed wrote...Tomorrow  I will squirt cleaner in it. if no joy there,  then scope therails is next.Be aware that control cleaners may contain flammable ingredients. Years ago, I found out the hard way when I sprayed a band switch in a Hallicrafters receiver with power applied. The minute arc caused by switching B+ ignited residual cleaner on the switch and burned a wafer. 73-- Brad AA1IP-- Sent from Postbox <https://www.postbox-inc.com>


Re: Repairing my Tektronix 454 oscilloscope need some advice

toby@...
 

On 2020-02-22 7:10 PM, Ed Breya via Groups.Io wrote:
With all this talk about HV stuff, I think it's a good time to introduce my HV curve-tracer/test box thing. I have been wrapping up the final design and features recently, and it's looking real good, with high utility for all sorts of HV device testing. ...
Anyway, it is moving along and working nicely, so I'll soon be able to put out some info on it. I'll report more as I finalize and draft up documents from my notes. I think some will find the system and design concepts interesting and useful.

Now, this whole deal may be considered OT here, since it isn't about Tek scopes per se, but I think the principles are very useful for checking out many of the problematic HV type components used in our scopes. So Dennis, if you don't want this here, please speak up ASAP, and I will refrain from further discussion.
Please don't refrain. This seems eminently relevant IMHO.

--Toby


Ed




Re: Weird 466 horizontal glitch-- be aware

Brad Thompson
 

Ed wrote...

Tomorrow I will squirt cleaner in it. if no joy there, then scope the
rails is next.
Be aware that control cleaners may contain flammable ingredients. Years ago, I found out the hard way when I sprayed a band switch in a Hallicrafters receiver with power applied. The minute arc caused by switching B+ ignited residual cleaner on the switch and burned a wafer. 73-- Brad AA1IP

--
Sent from Postbox <https://www.postbox-inc.com>


Re: Repairing my Tektronix 454 oscilloscope need some advice

Ed Breya
 

With all this talk about HV stuff, I think it's a good time to introduce my HV curve-tracer/test box thing. I have been wrapping up the final design and features recently, and it's looking real good, with high utility for all sorts of HV device testing. It's basically a low power, variable HV engine, using a 5 kV RMS "static-neutralizing" transformer, with various operating modes. A built in HV probe circuit, and special receivers for DUT return current and DC leakage, provide output signals to a scope and a DVM.

The HV engine has these main functions, selected by a SP8T HV switch:
FLOAT
-DC
-DC/sweep
AC/sweep
+DC/sweep
+DC
FLOAT
DISCHARGE

The AC is variable from ~0 to +/- 7500 V peak
The DC ones are variable from ~0 to 15 kV peak
The maximum steady-state current from any output is around 2 mA (shorted).

The HV probe drives a 1 meg scope input, with 1000:1 ratio, so 1V/kV.

The DUT return receiver absorbs the cold-end current, and drives another 1 meg scope input, with various ranges:
1V/mA, 2 kohm burden
1V/uA, 1 megohm parallel 200 pF burden
LOG (bipolar compression), about 4 mA/400 mV reference level, 1 kohm plus diode parallel 1.5 meg burden

The DC leakage receiver drives a DVM, and has internally selected termination Rs to accommodate DVMs with input R of 1 meg, 10 meg, or 1E9 and up.
It is especially useful for capacitor leakage testing, with low-pass filtering to reduce ripple current and interference. The ranges are:
1 V/mA, tau 1 sec, 2 kohm burden
1 V/uA, tau 1 sec, 1.1 meg burden
1V/uA, tau 11 sec, 1.1 meg burden

The receivers and other ports are protected from faults with spark gaps and other items. No equipment output signal can exceed 30 V.

My test setup with a 5 digit DVM, can resolve to 10 pA - but only after tens of minutes to allow settling of the dielectric absorption, and with maximum filtering, and with line voltage fairly stable (the HV is not regulated). This was on a .01 uf 5 kV ceramic cap - the rectangular type often found in old scopes - stressed at about 6500 V. I'm finding these caps are quite remarkable in performance, despite their age and being used. This particular unit settled at less than 100 pA with 6500 V, so well above E13 ohms, which I'd expect just from a good insulator, without any capacitance included. Of course, this is only at room temperature, with no other stresses applied, but it was quite surprising. I'll be reporting on the caps and other items separately - it's been a lot of fun checking things out, with interesting results.

There are also some other items and functions, jumper-selected on the working deck. These include 4600 pF of HV filter capacitance, clamp circuits to make +/- 2 kV and +/- 200 V, and a high R (160 meg) for DC leakage feed and other very low current uses. The 2 kV clamp makes a 4 kV pp trapezoidal wave, for amplitude calibration of the HV probe/scope combo, and the 200 V one makes a 400 V pp - at one-tenth the risetime - "square" wave, to adjust the probe and cable compensation.

Anyway, it is moving along and working nicely, so I'll soon be able to put out some info on it. I'll report more as I finalize and draft up documents from my notes. I think some will find the system and design concepts interesting and useful.

Now, this whole deal may be considered OT here, since it isn't about Tek scopes per se, but I think the principles are very useful for checking out many of the problematic HV type components used in our scopes. So Dennis, if you don't want this here, please speak up ASAP, and I will refrain from further discussion.

Ed


Re: Weird 466 horizontal glitch

Edward Prest
 

Tomorrow I will squirt cleaner in it. if no joy there, then scope the
rails is next.
While the primary z axis input looks clean, there is vertical board input
one transistor after this z input. very suspect.

On Sat, Feb 22, 2020 at 9:54 AM Mlynch001 <@mlynch001> wrote:

On Sat, Feb 22, 2020 at 08:23 AM, <prest.edward.3@...> wrote:


Good idea.
With beam finder pressed, it does not show the problem.This is an
important
clue!
in xy mode it does glitch too, as every other setting.

I have checked Z output and its clean. (it leaks the z sum even though
its an
input)

more reading the manual with emphasis on the differences with beam on
and off
next i guess
Edward,

I have found that dirty/sticking switches are a major problem in these
old scopes. I have had several 4XX Series scopes across the bench that
were "Cured" by a simple and thorough cleaning of all these type of
switches. Good luck in your repair.

--
Michael Lynch
Dardanelle, AR




Re: 547 scope HV transformer problem. One practical solution.

 

Hi Randy,

I had never heard of a 555 scope before. So I went online and saw a video showing it and explaining some details. There I learned about the filament voltage regulation with a saturable reactor. Smart idea! Then I downloaded the manual and peaked in it. The delay line with 12 tubes followed by multiple discrete-component stages! The two HV supplies, practically identical to my 547 scope! Multiplexing inputs with vacuum tube diodes! The magnitude of the instrument is amazing, and it must be a real pleasure to operate it. A 60 year old design that out-thrills by so far any modern $400 digital scope, no matter how modern technology has made high performance so easy. You are lucky!

Regards,
Ernesto


Re: Tekprobe 1103 PSU mod. advice

Mark Litwack
 

Hi Ancel,

Ok, a couple of pennies... Here's a project that's similar to what you're considering. Maybe you can use it as a starter:

https://www.eevblog.com/forum/circuit-studio/example-project-tektronix-tekprobe-adapterbreakout/msg1201386/#msg1201386

There's also this one, which has more of the power supply design you mention, but it doesn't mount to the scope's BNC:

https://www.eevblog.com/forum/projects/tektronix-tekprobe-power-supply-for-agilent-rigol-and-other-oscilloscopes/msg624284/#msg624284

-mark

On Sat, Feb 22, 2020 at 09:59 AM, Ancel wrote:


Hi all:
I am considering a project create a more convenient '1103' Tekprobe capability
for augmenting common O'scopes compatibility with the Tekprobe BNC interface.
My idea is to make compact individual TekProbe adapters to directly attach to
the BNC Probe inputs on O'scopes with no BNC cabling which degrade probe
performance with the stock 1103.
Given the common USB interface on modern O' scopes, I hope to use that as the
DC power supply to create the required +/-15V & +/- 5V required. An RJ45 cable
can carry the power from the USB boost SMPS supply to the new Tekprobe BNC
adapter. In this way the PSU SMPS 'noise' is isolated from the O'scopes BNC
input and can be managed by common mode chokes if required, while the twisted
pair should carry the clean power to the TekProbe adapters.
For older 'pre-USB' scopes, a ubiquitous 5V 'phone' power bank offers
convenient power.

So final outcomes are...convenient single BNC Tekprobe adapters not requiring
a Mains AC supply while offering improved signal fidelity/bandwidth and a
voltage ref. back light LED on each O'scope BNC adapter to validate the
precision voltage power function.

I have not included the '1103' offset voltage option due to size issues. It
might be possible but do you guys feel it is necessary?
Given the retail of the 1103's seem to range from $150 thru $450 USD these
days, I feel a compact $50 option is possible, with the benefit of improved
performance and V.reg.

Penny for your thoughts.....


Re: 547 scope HV transformer problem. One practical solution.

Randy Newman
 

Hi Ernesto.
As a happy 555 owner (beautiful sharp blue trace (p13 phosphor?). Re
washing, check the BAMA (Boat Anchor ....) and look in the tek section for
tektronix magazines....or maybe I am thinking of the w140.com site.
Yes...the latter...see the 111wiki, then section 38 manuals, catalogs, and
other publications...then "Tektronix magazines" Tekscope vol 8 no. 4
1976..has tek's scope washing procedure. This is a 2-parter..don't have the
other issue...might be vol 9 no. 1. Plus there is a wealth of information
on tube and xsistor scopes. I also have a 7834, 7633, and 7623. But I
really like the 555, even with its external supply(!!). Nice garage
heater....some day I will have a real shop area.
Hope this helps!

On Thu, Feb 20, 2020, 9:27 AM Ernesto <ebordon@...> wrote:

Hi John, thank you for pointing me to the world of oscilloscope washing,
cleaning.

I read about the experiences of others and the industry washing
oscilloscopes with water. The hairs on my head used to stand up at the
idea, but now I recognize that it is relatively safe, although it
requires WORK.
I compare it with my long experience of "don't fix what is not broken",
and the good luck I have with my old scope that had a 40 years leave of
absence.

I perfectly cleaned the exterior of my 547, and it is shiny. The inside
is different, with plenty of dust deposited on the tubes and surfaces. I
like to preserve it like that for its dramatic effect. The instrument will
be perfect for my grandchildren to play with it when they are a little
bigger, and it may awaken their interest in electronics. I plan to show
them the inside of the scope to be impressed with its age, but after that
the inside will be off limits to them.

But... if I experience any failures, I feel competent enough to trace
them to the failed component, or particles of dust, and I will remove
just those offending particles.

NOTE: I have a different standard for washing myself, staying clean inside
and changing my underwear, ha ha ha.

Cheers,
Ernesto




Re: Repairing my Tektronix 454 oscilloscope need some advice

Chuck Harris
 

Unlike most of the scope, the HV section can quite
easily catch itself on fire... This is because of
its easy ability to sustain arcing.

So, the beeswax, and old oil style capacitors, potentially
could have been little fire starters. I don't know that
they ever caused a fire, but this is the sort of stuff
that worries safety conscious engineers... especially
since the advent of UL, other safety standards, and
personal injury lawyers.

So, it would not surprise me at all to find out the
epoxy used in these transformers and door knob capacitors
might have been specified to be fire retardant.

Fire retardant materials have caused a host of problems
in all aspects of life. Fire retardant pajamas for
small children saved lives from fire, but were/are
poisonous to their little endocrine systems.

Fire retardant plastic cases for monitors, computers, and
keyboards shifted color from white to iodine brown as
they aged.

Another member of the group postulated that the brown
color in the failed epoxy was the same bromine brown
color that appears on the white fire retardant computer
cases... I am coming to believe that may be true.

-Chuck Harris

greenboxmaven via Groups.Io wrote:

I was doing some cleaning up in my shop and came across something  from a Tektronix
454 scope that resonates with this transformer discussion. I think "contaminated"
epoxy  may have caused another problem in a scope high voltage power supply. The 454
had several problems that were easy to find and remedy. It still would not give
anything more than a very pale glow on the screen. The second anode voltage was only
about 2,000 volts. Disconnecting the transformer from the tripler circuit gave a
husky corona arc to a screwdriver, so I began testing the diodes and condensers in
the multiplier circuit. As I reconnected each stage, the voltage incresed. Finally I
reconnected the 500 PFD "doorknob" condenser,and the voltage plummited. Having worked
on television receivers decades ago, I had several replacement condensers on hand,
and installing one brought the scope to life with a dazzling trace. One of the
NuVistors in the preamp was barely alive, so that channel could not be brought onto
the screen. A replacement got the scope working very well. I took the condenser over
to a friend who has a Hipot tester, and it was fine until the voltage reached about
2,000 volts. The condenser is rated at 20KV, and the voltage on it in the scope is
12KV. The bad condenser is epoxy molded, the 60 year old replacement is tan high
voltage bakelite. I wonder if Tektronix specified or accepted an epoxy formula that
goes bad?

      Bruce Gentry, KA2IVY


On 2/22/20 8:47 AM, Victor via Groups.Io wrote:
Albert,Thank you. I was looking for some information regarding the HV transformer
terminals and during the search I read a post from a member that repair the HV
circuit after found that C1460 has leakage current. Before made the measurement
that you recommend I decide to disconnect C1460 and see what happens. I was very
surprise when I energize the 454 and see flashing the terminals open at least 1cm
(1/2 inch) distance. I believe if this happens is because the HV increase maybe to
12kV...Then I disconnect the power and measure the C1460, between ground and the
terminal open with my Fluke, and get around 1Mohm...So my question is do you think
C1460 is dead ? How can be sure ?
Thanks,Victor


-----Original Message-----
From: Albert Otten <aodiversen@...>
To: TekScopes <TekScopes@groups.io>
Sent: Thu, Feb 20, 2020 11:05 pm
Subject: Re: [TekScopes] Repairing my Tektronix 454 oscilloscope need some advice

Victor,
I would first of all test the waveforms at terminals 7, 9 and 10 and check that the
amplitudes have more or less the same  ratios to each other (and perhaps to the 1 V
pp) as in my case. Your 52 V is really to low, so check it against the (negative)
peak voltage at terminal 9. The secondary waveforms may show a slightly flat
negative peak because of diode conduction, but only slightly. At terminal 9 the
negative "flat" peak was about 5 V smaller than the "round" positive peak.
Can you measure the primary current? Perhaps your generator can show the current
drawn?
For test HV diodes see the message by Chuck Harris or see message  #163125).

Albert

On Thu, Feb 20, 2020 at 09:42 PM, Victor wrote:
Albert,
This afternoon, I was reviewing the measurement done yesterday and found a
problem (intermittent connection) with the cable connecting the wave generator
to the Q1430 collector. After repair it I test again my 454 and now with a
1Vpp on the collector of the Q1430, I get 52V at the HV test point.So, with
this result I believe my HV transformer is Ok. I have a doubt about the HV
diodes... what do you think ? By the way how do you test HV diode,I understand
you cannot do it with a regular tester.Tomorrow before made the test that you
recommend today. I would like to review the HV CRT circuit to see if any
resistor or capacitor are out of specs (transistors have been test and look
good).
Thank you,Victor







Re: Repairing my Tektronix 454 oscilloscope need some advice

greenboxmaven
 

I was doing some cleaning up in my shop and came across something from a Tektronix 454 scope that resonates with this transformer discussion. I think "contaminated" epoxy may have caused another problem in a scope high voltage power supply. The 454 had several problems that were easy to find and remedy. It still would not give anything more than a very pale glow on the screen. The second anode voltage was only about 2,000 volts. Disconnecting the transformer from the tripler circuit gave a husky corona arc to a screwdriver, so I began testing the diodes and condensers in the multiplier circuit. As I reconnected each stage, the voltage incresed. Finally I reconnected the 500 PFD "doorknob" condenser,and the voltage plummited. Having worked on television receivers decades ago, I had several replacement condensers on hand, and installing one brought the scope to life with a dazzling trace. One of the NuVistors in the preamp was barely alive, so that channel could not be brought onto the screen. A replacement got the scope working very well. I took the condenser over to a friend who has a Hipot tester, and it was fine until the voltage reached about 2,000 volts. The condenser is rated at 20KV, and the voltage on it in the scope is 12KV. The bad condenser is epoxy molded, the 60 year old replacement is tan high voltage bakelite. I wonder if Tektronix specified or accepted an epoxy formula that goes bad?

Bruce Gentry, KA2IVY

On 2/22/20 8:47 AM, Victor via Groups.Io wrote:
Albert,Thank you. I was looking for some information regarding the HV transformer terminals and during the search I read a post from a member that repair the HV circuit after found that C1460 has leakage current. Before made the measurement that you recommend I decide to disconnect C1460 and see what happens. I was very surprise when I energize the 454 and see flashing the terminals open at least 1cm (1/2 inch) distance. I believe if this happens is because the HV increase maybe to 12kV...Then I disconnect the power and measure the C1460, between ground and the terminal open with my Fluke, and get around 1Mohm...So my question is do you think C1460 is dead ? How can be sure ?
Thanks,Victor


-----Original Message-----
From: Albert Otten <aodiversen@...>
To: TekScopes <TekScopes@groups.io>
Sent: Thu, Feb 20, 2020 11:05 pm
Subject: Re: [TekScopes] Repairing my Tektronix 454 oscilloscope need some advice

Victor,
I would first of all test the waveforms at terminals 7, 9 and 10 and check that the amplitudes have more or less the same ratios to each other (and perhaps to the 1 V pp) as in my case. Your 52 V is really to low, so check it against the (negative) peak voltage at terminal 9. The secondary waveforms may show a slightly flat negative peak because of diode conduction, but only slightly. At terminal 9 the negative "flat" peak was about 5 V smaller than the "round" positive peak.
Can you measure the primary current? Perhaps your generator can show the current drawn?
For test HV diodes see the message by Chuck Harris or see message #163125).

Albert

On Thu, Feb 20, 2020 at 09:42 PM, Victor wrote:
Albert,
This afternoon, I was reviewing the measurement done yesterday and found a
problem (intermittent connection) with the cable connecting the wave generator
to the Q1430 collector. After repair it I test again my 454 and now with a
1Vpp on the collector of the Q1430, I get 52V at the HV test point.So, with
this result I believe my HV transformer is Ok. I have a doubt about the HV
diodes... what do you think ? By the way how do you test HV diode,I understand
you cannot do it with a regular tester.Tomorrow before made the test that you
recommend today. I would like to review the HV CRT circuit to see if any
resistor or capacitor are out of specs (transistors have been test and look
good).
Thank you,Victor



Re: Repairing my Tektronix 454 oscilloscope need some advice

Victor
 

Albert, I hope so. Comparing my HV box with the pictures I saw, I am convinced that my 454 has been repaired at this level in the past. Diodes aren't the same series and different shape. Also terminal soldering aren't very clean.Victor

-----Original Message-----
From: Albert Otten <aodiversen@...>
To: TekScopes <TekScopes@groups.io>
Sent: Sat, Feb 22, 2020 5:12 pm
Subject: Re: [TekScopes] Repairing my Tektronix 454 oscilloscope need some advice

(continued) Those flashes after disconnecting C1460 indeed seem to indicate that C1460 was already bad.


Re: Repairing my Tektronix 454 oscilloscope need some advice

Victor
 

Albert, Thank you. Sorry, my move and idea was bad,I feel that when I saw the flashes. So I'm learning... now I need to find a new cap. I have in my "part box" some round capacitor capacitor but they are only 7500 V...Thank you for advice.Victor

-----Original Message-----
From: Albert Otten <aodiversen@...>
To: TekScopes <TekScopes@groups.io>
Sent: Sat, Feb 22, 2020 5:05 pm
Subject: Re: [TekScopes] Repairing my Tektronix 454 oscilloscope need some advice

Victor,
Regrettably you don't now whether C1460 went bad because of those flashes or was already bad. You shouldn't see even the slightest sign of leakage, the cap is gone.
A safer way to disconnect the PA voltage is to disconnect a diode earlier in the tripler chain. Unsoldering (and resoldering with silver containing solder) is somewhat risky I think. Best would be to lift the blank wire from "7" from the notch in the ceramic strip. If you do so you can test HV again. First I would set the HV pot form minimum HV in order to avoid damage to the CRT filament.
Albert


On Sat, Feb 22, 2020 at 02:47 PM, Victor wrote:


Albert,Thank you. I was looking for some information regarding the HV
transformer terminals and during the search I read a post from a member that
repair the HV circuit after found that C1460 has leakage current. Before made
the measurement that you recommend I decide to disconnect C1460 and see what
happens. I was very surprise when I energize the 454 and see flashing the
terminals open at least 1cm (1/2 inch) distance. I believe if this happens is
because the HV increase maybe to 12kV...Then I disconnect the power and
measure the C1460, between ground and the terminal open with my Fluke, and get
around 1Mohm...So my question is do you think C1460 is dead ? How can be sure
?
Thanks,Victor


80E02 80E03 Sample Module Repair

dalek
 

Hi. Has anyone had any success repairing these modules? I could find little to no information regarding the servicing of them.
Richard


Re: Repairing my Tektronix 454 oscilloscope need some advice

Albert Otten
 

(continued) Those flashes after disconnecting C1460 indeed seem to indicate that C1460 was already bad.


Re: Repairing my Tektronix 454 oscilloscope need some advice

Albert Otten
 

Victor,
Regrettably you don't now whether C1460 went bad because of those flashes or was already bad. You shouldn't see even the slightest sign of leakage, the cap is gone.
A safer way to disconnect the PA voltage is to disconnect a diode earlier in the tripler chain. Unsoldering (and resoldering with silver containing solder) is somewhat risky I think. Best would be to lift the blank wire from "7" from the notch in the ceramic strip. If you do so you can test HV again. First I would set the HV pot form minimum HV in order to avoid damage to the CRT filament.
Albert

On Sat, Feb 22, 2020 at 02:47 PM, Victor wrote:


Albert,Thank you. I was looking for some information regarding the HV
transformer terminals and during the search I read a post from a member that
repair the HV circuit after found that C1460 has leakage current. Before made
the measurement that you recommend I decide to disconnect C1460 and see what
happens. I was very surprise when I energize the 454 and see flashing the
terminals open at least 1cm (1/2 inch) distance. I believe if this happens is
because the HV increase maybe to 12kV...Then I disconnect the power and
measure the C1460, between ground and the terminal open with my Fluke, and get
around 1Mohm...So my question is do you think C1460 is dead ? How can be sure
?
Thanks,Victor


Tekprobe 1103 PSU mod. advice

 

Hi all:
I am considering a project create a more convenient '1103' Tekprobe capability for augmenting common O'scopes compatibility with the Tekprobe BNC interface.
My idea is to make compact individual TekProbe adapters to directly attach to the BNC Probe inputs on O'scopes with no BNC cabling which degrade probe performance with the stock 1103.
Given the common USB interface on modern O' scopes, I hope to use that as the DC power supply to create the required +/-15V & +/- 5V required. An RJ45 cable can carry the power from the USB boost SMPS supply to the new Tekprobe BNC adapter. In this way the PSU SMPS 'noise' is isolated from the O'scopes BNC input and can be managed by common mode chokes if required, while the twisted pair should carry the clean power to the TekProbe adapters.
For older 'pre-USB' scopes, a ubiquitous 5V 'phone' power bank offers convenient power.

So final outcomes are...convenient single BNC Tekprobe adapters not requiring a Mains AC supply while offering improved signal fidelity/bandwidth and a voltage ref. back light LED on each O'scope BNC adapter to validate the precision voltage power function.

I have not included the '1103' offset voltage option due to size issues. It might be possible but do you guys feel it is necessary?
Given the retail of the 1103's seem to range from $150 thru $450 USD these days, I feel a compact $50 option is possible, with the benefit of improved performance and V.reg.

Penny for your thoughts.....


Re: Weird 466 horizontal glitch

Mlynch001
 

On Sat, Feb 22, 2020 at 08:23 AM, <prest.edward.3@...> wrote:


Good idea.
With beam finder pressed, it does not show the problem.This is an important
clue!
in xy mode it does glitch too, as every other setting.

I have checked Z output and its clean. (it leaks the z sum even though its an
input)

more reading the manual with emphasis on the differences with beam on and off
next i guess
Edward,

I have found that dirty/sticking switches are a major problem in these old scopes. I have had several 4XX Series scopes across the bench that were "Cured" by a simple and thorough cleaning of all these type of switches. Good luck in your repair.

--
Michael Lynch
Dardanelle, AR


Re: TDS460A Will not turn on?

Mlynch001
 

On Sat, Feb 22, 2020 at 12:56 AM, <toby@...> wrote:



Fantastic! As a fellow TDS 460A owner, I am quite impressed and pleased
you got it going again. Once again the list collects an important repair
story for posterity...

--Toby
Toby,

Thank you! I really like the TDS460A as it has some very useful features. I bought this one on E-Pay No Reserve Auction for less than $50 USD, including freight. It was listed as "not-working" and "parts only". To my surprise, it fired right up as soon as I unboxed it and Passed all the self tests. I used it for about a year, until the Power supply suddenly died. So I have almost nothing invested in a very capable scope and have received a very important education into SMPS design and repair. I now have two 460A's and both working,with almost no monetary investment.


--
Michael Lynch
Dardanelle, AR