Topics

Digital scope with CRT


Ondrej Pavelka
 

Hi folks, what was the latest CRT digital scope TEK ever made? I have a friend student on a budget and he enjoys fixing old computers and hes becoming rather good at it. He is looking for scope to help him in his endeavours. I am almost thinking hybrid LA/scope could be the thing for him but are those in couple hundred dollars range?


Siggi
 

Hey Ondrej,

I'm not sure I understand what you're after. Are you looking for a realtime
digitizing scope with a CRT display? This as opposed to e.g. a sampling
scope, or a conventional, analog CRT scope, or a realtime digitizing scope
with an LCD?
If so, there's quite a range to select from, going back to e.g. 7854
(though it's not realtime - it's a sampling scope I believe), through some
2200s, through the 2430/2440 and all the way to the TDS series. I have a
2430 and a TDS784D, which are quite far apart in time and capability. You
might be able to get something like a TDS420/460 for a couple of hundred
bucks, though they'd be likely to become a repair project, as some/many/all
of those suffered capacitor plaque.

I don't know of any Tek LA/scope hybrids, but I also have a HP 54622D,
which is 2CH analog scope with 16 digital channels. If you can get one of
those for a couple of hundred bucks with logic probes, that'd make an
awesome beginner scope. You might need to be patient or lucky, but it does
happen. Mind that you get the logic probes, though, as those are impossible
to get except for ugly money, it looks like.

Siggi

On Mon, Aug 24, 2020 at 6:23 PM Ondrej Pavelka <info@...>
wrote:

Hi folks, what was the latest CRT digital scope TEK ever made? I have a
friend student on a budget and he enjoys fixing old computers and hes
becoming rather good at it. He is looking for scope to help him in his
endeavours. I am almost thinking hybrid LA/scope could be the thing for him
but are those in couple hundred dollars range?




toby@...
 

On 2020-08-24 6:23 p.m., Ondrej Pavelka wrote:
Hi folks, what was the latest CRT digital scope TEK ever made? I have a friend student on a budget and he enjoys fixing old computers and hes becoming rather good at it. He is looking for scope to help him in his endeavours. I am almost thinking hybrid LA/scope could be the thing for him but are those in couple hundred dollars range?

I don't know about "latest", but the CRT TDS4xx family are easy to use
and just great all-round scopes.

My TDS460A has served me extremely well and I highly recommend it and peers.

--Toby






Roy Thistle
 

On Mon, Aug 24, 2020 at 03:23 PM, Ondrej Pavelka wrote:


I have a friend student on a budget and he enjoys fixing old computers
All and every modern laptop/phone/tablet/TV repair shop I know of... none of them even have an oscilloscope... let alone a DSO (CRT display or not.) I even bought a few 24xx series, and 400 series scopes from repair shops. (They just never used them.) Those were good deals.
I've heard of a lot of reasons to want a Tek scope... like they are so darn cute, or they make good clocks... but never... "I need an oscilloscope to fix my computer... unless you mean your computer is an IBM 360... then you want a 453 with the IBM logo on it... don't you know?


Dave Seiter
 

That's because they no longer repair anything, they just swap out subassemblies. But it's understandable; I got a free 4KTV a few years ago that wouldn't turn on, but the power supplies were ok.  The problem was in the standby circuit, all of which was on a small PCB containing the IR receiver, some disc-type pushbutton switches and a few discretes.  I had to use a microscope to try and decipher the circuit, but never quite got a handle on what was going on- too many open ends.  I finally gave up after finding another free 4KTV (working this time).
-Dave

On Monday, August 24, 2020, 09:12:45 PM PDT, Roy Thistle <roy.thistle@...> wrote:

On Mon, Aug 24, 2020 at 03:23 PM, Ondrej Pavelka wrote:


I have a friend student on a budget and he enjoys fixing old computers
All and every modern laptop/phone/tablet/TV repair shop I know of... none of them even have an oscilloscope... let alone a DSO (CRT display or not.) I even bought a few 24xx series, and 400 series scopes from repair shops. (They just never used them.) Those were good deals.
I've heard of a lot of reasons to want a Tek scope... like they are so darn cute, or they make good clocks... but never... "I need an oscilloscope to fix my computer... unless you mean your computer is an IBM 360... then you want a 453 with the IBM logo on it... don't you know?


Ondrej Pavelka
 

Hi Dave, he does component level repairs of old computers up to say 486
era. He fixed several motherboards, video cards and hard drives even
without a scope, often it's trace damage repair, capacitor swap or whatever
is required. I am amazed how he was actually able to diagnose the problem
without a scope, but he does.

Those HP hybrids look good, Tek only ever did TLS216 to my knowledge.

O.

On Tue, 25 Aug 2020, 06:31 Dave Seiter, <d.seiter@...> wrote:

That's because they no longer repair anything, they just swap out
subassemblies. But it's understandable; I got a free 4KTV a few years ago
that wouldn't turn on, but the power supplies were ok. The problem was in
the standby circuit, all of which was on a small PCB containing the IR
receiver, some disc-type pushbutton switches and a few discretes. I had to
use a microscope to try and decipher the circuit, but never quite got a
handle on what was going on- too many open ends. I finally gave up after
finding another free 4KTV (working this time).
-Dave
On Monday, August 24, 2020, 09:12:45 PM PDT, Roy Thistle <
roy.thistle@...> wrote:

On Mon, Aug 24, 2020 at 03:23 PM, Ondrej Pavelka wrote:


I have a friend student on a budget and he enjoys fixing old computers
All and every modern laptop/phone/tablet/TV repair shop I know of... none
of them even have an oscilloscope... let alone a DSO (CRT display or not.)
I even bought a few 24xx series, and 400 series scopes from repair shops.
(They just never used them.) Those were good deals.
I've heard of a lot of reasons to want a Tek scope... like they are so
darn cute, or they make good clocks... but never... "I need an oscilloscope
to fix my computer... unless you mean your computer is an IBM 360... then
you want a 453 with the IBM logo on it... don't you know?






Thomas Garson
 

Nothing to see here, just a lot of pissing and moaning about the state of things.......

There are lots of reasons to have a 'scope in a computer repair shop. That is, if the technician has the ability to do component level troubleshooting. I have repaired mother boards several times by replacing failed caps in the on board switching supplies and, occasionally, bad power MOSFETs.

I built a reflow oven which I have used to correct boards with intermittent problems, which are often solder related. If it often works, then doesn't, then does, and seems to be heat or slight mechanical stress related, put it in the oven and reflow it. If that fixes it, great, if not, you have the very valuable knowledge that the problem is most likely not solder related. Sometimes a marginal part that is causing a problem will fail after the reflow heat & cool process. I still regard this as a win because either I can find the part and implement a repair, or I can't, which makes the board definitively junk, resulting in no remorse for replacing it.

Most big box computer store "techs" couldn't fix a 1960 Bell Telephone. They are not at all knowledgeable about electronics. The younger ones don't even get 1s and 0s. I know a fellow who is not a student of electronics or a hobbyist. In fact, is pursuing a law degree but is working as a fill time computer "Geek" at one of those Big Box Stores. Why, because he has a great vocabulary and can look a customer straight in the eye and lie. If it doesn't unplug, its a magic part. The MO is to replace boards, memory and CPU until it works, or you've built a new computer, either is an acceptable result. They NEVER fix power supplies. Of course, with computer power supplies being so cheap. I'm nuts for fixing mine.

A few Of the afore mentioned techs do know how to run hardware manufacturers diagnostic software. Those are Supervisor Grade techs.

If the problem is in software, they restore from a good backup. If that doesn't exist, they reinstall the O/S and all applications. To be fair, Windows configuration is so convoluted that it is near to impossible to trace and cure a problem in the setup or install of a program. The registry has become an okeydoke. This is all intentional on the part of Microsoft. I use Linux, which is much better but there are still times when it is just more expedient to wipe and reinstall the O/S than to chase.

Back in the DOS days, lots of people, including me, knew how to enter the bios, or call it, and run a particular hardware boot up diagnostics routine for testing purposes, Alternatively, you could write a small program in Macro Assembler or inline in C or Pascal that tested the questionable hardware. If you knew where to look, you could set and check interrupts, port flags, etc with a scope.

To be fair, it's almost impossible to get a schematic of any computer board, mother or plugin. I blame the government for that. Laws have been passed to force manufacturers to provide documents adequate for qualified persons to implement repairs and to have the parts to do it with, for up to 7 years. Neither executive nor legislative branch want those laws enforced due to campaign "considerations". Judges can't enforce laws that prosecutors and law enforcement don't bring violations of before them. Law enforcement has given up because there is no prosecution.

Computerized appliances are often a different story. I am able to repair digitally controlled and PWM audio amplifiers, optical disc players, etc. and I regularly use an oscilloscope in this process. This is made possible because schematics, images of data stream patterns and sometimes even truth tables, are often available from the manufacturer. There are times, however, when that doesn't help. I couldn't repair my big Mitsubishi flat screen TV even with a service manual in hand because those b_______ had embedded the pixel driver and decoding logic inside the display module and sealed it all up. Mitsubishi Factory Service can't even fix them. If you lost a line, column or color plane, it was junk.

Thomas Garson
Aural Technology, Ashland, OR
By my calculation, the dynamic range of the universe is roughly 679dB,
which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.

On 8/24/20 9:12 PM, Roy Thistle wrote:
On Mon, Aug 24, 2020 at 03:23 PM, Ondrej Pavelka wrote:


I have a friend student on a budget and he enjoys fixing old computers
All and every modern laptop/phone/tablet/TV repair shop I know of... none of them even have an oscilloscope... let alone a DSO (CRT display or not.) I even bought a few 24xx series, and 400 series scopes from repair shops. (They just never used them.) Those were good deals.
I've heard of a lot of reasons to want a Tek scope... like they are so darn cute, or they make good clocks... but never... "I need an oscilloscope to fix my computer... unless you mean your computer is an IBM 360... then you want a 453 with the IBM logo on it... don't you know?


Roy Thistle
 

On Mon, Aug 24, 2020 at 09:31 PM, Dave Seiter wrote:


That's because they no longer repair anything
Nope.
I took my phone to a friends shop, here in the colonies. He let me watch... and he quickly found a shorted sm cap, and a blown power management chip... also he replaced the charging port. He hot aired off the replacement power management chip, from a parts mule.
He let me watch... and he is what I saw he had in the shop...
good power supply with a good current limit.
good but not great bench type multimeter
average hand held multimeter
thermal probe for the hand held multimeter
some Chinese clone of a Flir thermal image camera or the equivalent
high quality hot air station with lots of nozzels
good soldering iron/station... with a custom? tip(s)
high quality solder braid
chipquick or equivalent
flux (I prefer rosin... but he had some expensive chemical stuff)
Lots of isopropyl
lighter fluid
good stereo microscope, on an swivel/extender mount, including a camera
subscription to Internet schematic service.
an absolute pile of parts mules.
a clever, resourceful, and adaptable human mind
and... you guessed it... no scope!


Jim Ford
 

Funny you should mention it, Thomas; the IEEE just today sent me a message about the Right to Repair bill.  Yep, sounds like a good idea to me.  Don't force us to pay through the nose for "repair" services from the manufacturers and don't keep schematics and other documentation secret from us consumers.  I can forward the email from the IEEE if you like. Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Thomas Garson <tgarson@...> Date: 8/24/20 11:20 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Digital scope with CRT Nothing to see here, just a lot of pissing and moaning about the state of things.......There are lots of reasons to have a 'scope in a computer repair shop. That is, if the technician has the ability to do component level troubleshooting. I have repaired mother boards several times by replacing failed caps in the on board switching supplies and, occasionally, bad power MOSFETs.I built a reflow oven which I have used to correct boards with intermittent problems, which are often solder related. If it often works, then doesn't, then does, and seems to be heat or slight mechanical stress related, put it in the oven and reflow it. If that fixes it, great, if not, you have the very valuable knowledge that the problem is most likely not solder related. Sometimes a marginal part that is causing a problem will fail after the reflow heat & cool process. I still regard this as a win because either I can find the part and implement a repair, or I can't, which makes the board definitively junk, resulting in no remorse for replacing it.Most big box computer store "techs" couldn't fix a 1960 Bell Telephone. They are not at all knowledgeable about electronics. The younger ones don't even get 1s and 0s. I know a fellow who is not a student of electronics or a hobbyist. In fact, is pursuing a law degree but is working as a fill time computer "Geek" at one of those Big Box Stores. Why, because he has a great vocabulary and can look a customer straight in the eye and lie. If it doesn't unplug, its a magic part. The MO is to replace boards, memory and CPU until it works, or you've built a new computer, either is an acceptable result. They NEVER fix power supplies. Of course, with computer power supplies being so cheap. I'm nuts for fixing mine.A few Of the afore mentioned techs do know how to run hardware manufacturers diagnostic software. Those are Supervisor Grade techs.If the problem is in software, they restore from a good backup. If that doesn't exist, they reinstall the O/S and all applications. To be fair, Windows configuration is so convoluted that it is near to impossible to trace and cure a problem in the setup or install of a program. The registry has become an okeydoke. This is all intentional on the part of Microsoft. I use Linux, which is much better but there are still times when it is just more expedient to wipe and reinstall the O/S than to chase.Back in the DOS days, lots of people, including me, knew how to enter the bios, or call it, and run a particular hardware boot up diagnostics routine for testing purposes, Alternatively, you could write a small program in Macro Assembler or inline in C or Pascal that tested the questionable hardware. If you knew where to look, you could set and check interrupts, port flags, etc with a scope.To be fair, it's almost impossible to get a schematic of any computer board, mother or plugin. I blame the government for that. Laws have been passed to force manufacturers to provide documents adequate for qualified persons to implement repairs and to have the parts to do it with, for up to 7 years. Neither executive nor legislative branch want those laws enforced due to campaign "considerations". Judges can't enforce laws that prosecutors and law enforcement don't bring violations of before them. Law enforcement has given up because there is no prosecution.Computerized appliances are often a different story. I am able to repair digitally controlled and PWM audio amplifiers, optical disc players, etc. and I regularly use an oscilloscope in this process. This is made possible because schematics, images of data stream patterns and sometimes even truth tables, are often available from the manufacturer. There are times, however, when that doesn't help. I couldn't repair my big Mitsubishi flat screen TV even with a service manual in hand because those b_______ had embedded the pixel driver and decoding logic inside the display module and sealed it all up. Mitsubishi Factory Service can't even fix them. If you lost a line, column or color plane, it was junk.Thomas GarsonAural Technology, Ashland, ORBy my calculation, the  dynamic range of the universe is roughly 679dB,which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.On 8/24/20 9:12 PM, Roy Thistle wrote:> On Mon, Aug 24, 2020 at 03:23 PM, Ondrej Pavelka wrote:> >>>> I have a friend student on a budget and he enjoys fixing old computers>>> All and every modern laptop/phone/tablet/TV repair shop I know of... none of them even have an oscilloscope... let alone a DSO (CRT display or not.) I even bought a few 24xx series, and 400 series scopes from repair shops. (They just never used them.) Those were good deals.> I've heard of a lot of reasons to want a Tek scope... like they are so darn cute, or they make good clocks... but never... "I need an oscilloscope to fix my computer... unless you mean your computer is an IBM 360... then you want a 453 with the IBM logo on it... don't you know?> > > > >


 

Please post their email here.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim Ford
Sent: 26 August 2020 04:29
To: TekScopes@groups.io
Subject: Re: [TekScopes] Digital scope with CRT

Funny you should mention it, Thomas; the IEEE just today sent me a message about the Right to Repair bill. Yep, sounds like a good idea to me. Don't force us to pay through the nose for "repair" services from the manufacturers and don't keep schematics and other documentation secret from us consumers. I can forward the email from the IEEE if you like.


Jim Ford
 

-------- Original message --------From: "David C. Partridge" <@perdrix> Date: 8/26/20 1:39 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Digital scope with CRT Please post their email here.David-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim FordSent: 26 August 2020 04:29To: TekScopes@...: Re: [TekScopes] Digital scope with CRTFunny you should mention it, Thomas; the IEEE just today sent me a message about the Right to Repair bill.  Yep, sounds like a good idea to me.  Don't force us to pay through the nose for "repair" services from the manufacturers and don't keep schematics and other documentation secret from us consumers.  I can forward the email from the IEEE if you like.


Renée
 

On 8/26/20 1:39 PM, David C. Partridge wrote:
Please post their email here.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim Ford
Sent: 26 August 2020 04:29
To: TekScopes@groups.io
Subject: Re: [TekScopes] Digital scope with CRT

Funny you should mention it, Thomas; the IEEE just today sent me a message about the Right to Repair bill. Yep, sounds like a good idea to me. Don't force us to pay through the nose for "repair" services from the manufacturers and don't keep schematics and other documentation secret from us consumers. I can forward the email from the IEEE if you like.