Tektronix 455 VS HumgChang 5502

[oldway]

Some analog scopes.

Left top: Philips PM3233 10Mhz 2 beams with long decay phosphor
Left midden: Tektroniks 2235 100Mhz 2 channels 2 time bases
Left bottom: Philips/Flule PM3094 200Mhz 2 time bases, cursors, 4 channels
Mid top: BBC Metrawatt M6004 100Mhz 2 channels 2 time bases rebranded Hameg HM1005.
Mid Midden: Hameg HM 605 60Mhz 2 channels with delay and component tester
Mid bottom: Hameg HM1505 150Mhz 2 channels 2 timebases, cursors and component tester.
Right top: HP1740A 100Mhz  2 channels
Right bottom: HP1725A 275Mhz 2 channels

[amemic]

Some analog scopes.

Left top: Philips PM3233 10Mhz 2 beams with long decay phosphor
Left midden: Tektroniks 2235 100Mhz 2 channels 2 time bases
Left bottom: Philips/Flule PM3094 200Mhz 2 time bases, cursors, 4 channels
Mid top: BBC Metrawatt M6004 100Mhz 2 channels 2 time bases rebranded Hameg HM1005.
Mid Midden: Hameg HM 605 60Mhz 2 channels with delay and component tester
Mid bottom: Hameg HM1505 150Mhz 2 channels 2 timebases, cursors and component tester.
Right top: HP1740A 100Mhz  2 channels
Right bottom: HP1725A 275Mhz 2 channels

 Nice collection, are you offering to donate that HM605? 

[oldway]

Nice collection, are you offering to donate that HM605? 

That's my workhorse ...
I was repairing analog scopes, that's the reason why I succeded such a collection...and they are not all on the picture !

There are some people who think they are useless...they should donate their old analog scope !
But it is not what happen...instead, it is harder and harder to find a cheap HM605 !

[amemic]

They are not useless at all, and I don't think they will be anytime soon...

Yeah that is true...Hamegs are really holding their price... :-D

[tautech]

Some analog scopes.

Nice collection. 

I thought you must have a strong bench. 
Then I enlarged the image to see the sag in your shelf. 
100 kg +?

Put a support under the shelf Oldway, I would hate to hear that it broke one day. 

[oldway]

It was only to take the picture 
Nothing wrong happened...
I also have a tek 465B (working), a tek 2236 (not 100% funcional), another HP1740A (not working, for parts) and an HP1715A (not working, for parts)

[Rupunzell]

What happened on this thread occurs more often than not is due to a specific individual(s) that hold the opinion that all analog CRT based real time O'scopes are utter outdated technology that should be relegated to the scrap heap or museum and the only time domain instrument worth using in these modern times is a DSO, no exceptions.

Facts and the technical realities are both analog CRT & DSO have their place for instrumentation needs and those who are wise will have both using what meets the specific instrumentation needs best. To automatically and generalize that Analog CRT O'scope are all useless is quite blind and truly ignorant.

What appears that has happened after the market wide acceptance and dominance of DSOs is the agent of the data box which essentially reads out and interprets the graphic display for the user in many ways relegating the basic skills of using a time domain instrument secondary.

Over reliance of this data box and techno feature baked into the modern DSO can become a handicap beyond it's instant data presentation.
IMO, learn the O'scope basics on a good analog O'scope. Once these fundamentals have been mastered and well understood, then move on to a DSO with a full understanding of it's limitations.

There is just a HUGE amount of information available on a good high quality analog CRT based O'scope, problem is it takes skill, knowledge and more to fully utilize this information. Granted this display will not provide instant frequency measurement out to several digits of accuracy or display rise-fall time or amplitude to several digits of accuracy and all those signal chopped to bits advantages. This perceived advantage does come with many traps that users must be aware of or there will be more than a few hidden and user deceptive problems.

Another very worth while read is Jim Williams Ap note# 47 for O'scope users Analog CRT or DSO.
http://cds.linear.com/docs/en/application-note/an47fa.pdf


Bernice

Guys, I just wanted to pick and choose between available scopes,I didn't think that it will turn into  Analog vs digital discussion 

I am personally old-school guy, and I do like the old timey analogy stuff, but I do also realize goodness and advantage of the new digital technology, but it doesn't mean that either is a must have...truth to be told it would be best if you had both..
Although what I've noticed with all new technology, just like with phones and calculators, it spoils us, very few people today knows someones phone number, it's all in the phone, no one does the math without calculator, you can see where I'm going with this...we're putting less and less effort in things we do...many would say that's progress...is it really?

In the end, I will try to get my hands on the Tek, and only in case I'm not able to get it in any way, I'll go for the HungChang...darn it...in the end, if I finalyy get a raise this mont maybe I get both


@alsetalokin: Well, I do know how to work with a analog one, even so, as I said in earlier post, I had an entire class devoted to measurment instruments, including the scope...but I guess I am a bit rusty... :-)

[oldway]

In most applications, the accuracy of 5% of voltage's and rise time's measurements is sufficient.

That is what is obtained with a calibrated analog oscilloscope.

But for frequencies, this is often insufficient.
Some oscilloscopes have an Y amplifier output for the A channel on the rear panel.
This is the case with the Hameg HM605.
I have a HP5315A counter plugged into the amplifier output Y so I have a precise measurement of the frequency.

[Rupunzell]

5% accuracy for amplitude and rise-fall time is often good enough. Unless the circuit involved absolutely requires extreme precision, most analog designs should work using 10% tolerance parts without difficulty. If they do not, producing them can result in a lot of problems. 

Amplitude, frequency, rise-fall time and all that is only the beginning of the amount of information available in the waveform display of a good analog CRT O'scope.

The vertical channel out can be routed to a counter, Spectrum Analyzer, cascaded into the other vertical channel to increase gain trading off noise and BW and... (user beware as the amplifier output on most every instrument can have distortions & noise that can give false reading in instruments like a spectrum analyzer or ...)

If greater accuracy is needed for these types of measurements. There are far better instruments to use like a hp 3403C thermal converter based AC voltmeter, RF power meter, frequency counter, network analyzer, impedance analyzer and...

The traditional basic four items of electronics instrumentation would be Power Supply, Volt-Ohm Milliamp meter (digital or analog), Signal generator and O'scope. What appears to have happened in recent times is the heaping on of features into the modern DSO where it is trying to become time domain instrument, frequency domain instrument, signal source, precision volt meter, precision frequency counter and every other instrument all crammed into one box becoming Jack-Of-All-Trades, Master of None. This is not a bad thing in itself, but users MUST be aware of the inherent limitations when all this stuff is crammed into a single box of instrumentation.

Mostly made possible due low cost reasonable performance to A/D and D/A conversion and lots of computing power with low cost memory, But it still has every limitation baked into a sampled data conversion system.
 
One more item, most analog CRT O'scopes do not broadcast much RFI conducted or transmitted. I'm not convinced modern PC based instruments produce near zero RFI pollution into it's operating environment which might or might not be a problem.


Bernice

In most applications, the accuracy of 5% of voltage's and rise time's measurements is sufficient.

That is what is obtained with a calibrated analog oscilloscope.

But for frequencies, this is often insufficient.
Some oscilloscopes have an Y amplifier output for the A channel on the rear panel.
This is the case with the Hameg HM605.
I have a HP5315A counter plugged into the amplifier output Y so I have a precise measurement of the frequency.

[tautech]

One more item, most analog CRT O'scopes do not broadcast much RFI conducted or transmitted. I'm not convinced modern PC based instruments produce near zero RFI pollution into it's operating environment which might or might not be a problem.

This view is only partly correct when you consider that even quite old CRO's use SMPS for the main PSU and HV, even older units also used SMPS for HV supply and the only CRO's that I'm aware that don't use switchers are some Hamegs.
We often know by experience what frequencies to ignore and near field RFI investigation of TE will tell us what is not in Service manuals.

The vast majority of TE is SMPS powered these days, it is something we must accept and adapt to.

[oldway]

even older units also used SMPS for HV supply

That's not right...they are sinus oscillators and not SMPS...You think they are flyback as TV's sets but it is wrong.

NB: you have two kinds of CRT's:
- for low cost, low frequency scopes (20Mhz scopes), you need only one accelerating voltage ( more or less - 2000V) which is generaly coming from the main transformer and voltage multiplier, with voltage regulating circuit.

- for higher frequencies, (60 and more Mhz), you need a faster writing speed and a beam with more energy...for this reason, you have another accelerating voltage (PDA crt's, post deflection accelerating voltage) of 10 to 20Kv's.

[tautech]

even older units also used SMPS for HV supply

That's not right...they are sinus oscillators and not SMPS...You think they are flyback as TV's sets but it is wrong.

Thanks for the correction.

But are they EMI free? 

[oldway]

But are they EMI free? 

Analog scopes are not EMI free. I remember that there is a special military version of Tektronix 2235A with low EMI.
But the HV oscillators works at low frequencies (more or less 30Khz) with little harmonics.

Once, I repaired an analog scope who had a flyback transformer, same as those used in old TV's sets...
I don't remember the brand, I think it was an Hitachi ...but that's the only one I have seen with a flyback transformer.

Nb: if you intend to use your scope for repair, I recomand to buy a scope with component tester.
Some analog scopes with this feature: most of the analog scopes of Hameg (not the HM1005), Hung Tchang OS-620...

[Rupunzell]

That remains strictly driven by measurement instrumentation needs.

For the majority of folks working with digital and related systems and other switching centric devices, all that RF pollutions might be perfectly acceptable and not ever a factor.

Then there are folks who don't work with much of any of that switching digital stuff resulting in this group of crusty curm-crone-Mudgeons, that hold on to their older non-digital centric instrumentation for their lower RF pollution and other technical aspects. The number of Silicone Valley companies that still have non SMPS powered instrumentation could surprise more than a few.

As the "electronics" industry has become cyber-centric, energy efficient centric and generally software and data centric the traditional electronics industry has become much of a speciality. Yet the non digital-cyber-software-data centric areas of the electronics industry has not died off as most predicted. Instead it has grown in surprising ways.

Newer is not always better, if is often just different. Those who are wise and experience will discard current fashion and focus on the specifics that fits the measurement and instrumentation needs best, not what is proclaimed as the latest and greatest. The flip side of this has much to do with marketing, capital equipment expenditures related to taxes and how the accounting folks will allow the engineering folks to spend company funds.


Bernice

 

The vast majority of TE is SMPS powered these days, it is something we must accept and adapt to.

[Rupunzell]

Hold a 10X, 10meg divider scope probe tip directly at the trace displayed on the CRT with the vertical amp set to it's highest sensitivity. What will be displayed would be the probe picking up the RFI streaming off the front of the CRT. This is another source of RF pollution. The common solution to this is to install a fine metal (often copper) screen that is connected to the O'scope's chassis ground in front of the CRT. This significantly reduces this specific form of RF pollution and enhances CRT display contrast.

Many of the boat anchor Tek main frames used a resonant sine converter to produce the HV for the CRT. These have low noise and don't produce much RF pollution as they are pretty well shielded within the system and reasonably decoupled from the system power supply preventing this stuff from appearing at the AC power mains input via the power transformer and system ground.

The Tek 547 has a very traditional transformer with regulator power supply with a resonant sine converter for the HV, this results in a low noise O'scope in many ways. Jim Williams did more than one app note on low noise HV converters and a video on just how low noise they can be when done properly. Just one of the many circuit lessons that is available from learning about the Tek 547.
http://www.edn.com/design/analog/4348233/EDN-Access--03-16-95-Tripping-the-light-fantastic-a-case-study-in-circuit-desig



Beyond boat anchor analog CRT O'scopes, there are a good number of boat anchor RF signal sources, power meters, spectrum analyzers and.. that features well shielded, low noise, low RF pollution to the system power supplies.

 
 
Bernice

But are they EMI free? 

Analog scopes are not EMI free. I remember that there is a special military version of Tektronix 2235A with low EMI.
But the HV oscillators works at low frequencies (more or less 30Khz) with little harmonics.

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