Old analog or modern digital oscilloscope for low budget. Need advice.

[nctnico]

Those GW-Instek oscilloscopes from ITT Tech do look like a good deal except for lack of service documentation.  Of course even with service documentation, their surface mount construction could make maintenance difficult.

IMHO service documentation is very much overrated. Tektronix and HP machines usually have a few custom chips or EPROMs which can go bad so even with service documentation you are left with a unit which needs an extra (self designed) board to become operational again. For a modern EE SMT components should not be a problem. Also most equipment works using publicly known methods so with some ingenuity you can identify the function of a component (or group of components) and go from there. I've repaired lots of equipment without schematics.

[David Hess]

Those GW-Instek oscilloscopes from ITT Tech do look like a good deal except for lack of service documentation.  Of course even with service documentation, their surface mount construction could make maintenance difficult.

IMHO service documentation is very much overrated. Tektronix and HP machines usually have a few custom chips or EPROMs which can go bad so even with service documentation you are left with a unit which needs an extra (self designed) board to become operational again. For a modern EE SMT components should not be a problem. Also most equipment works using publicly known methods so with some ingenuity you can identify the function of a component (or group of components) and go from there. I've repaired lots of equipment without schematics.

The most likely problems involve power supplies, sensitive inputs, and mechanical parts rather than custom semiconductor and passive parts which are likely to be integrated circuits and hybrids which have higher reliability.

I have repaired lots of equipment without service documentation but I did not like it and it was always easier to do with service documentation.

For an experienced electronics technician or electronics engineer, I would recommend a well documented Tektronix 465B or later oscilloscope instead of a newer but undocumented alternative unless the later was very inexpensive.  As it ends up though, there is some pretty good service documentation for the GOS-6112 available online.

[T@ller]

Guys.

Look on this Tek 2246:
http://www.ebay.com/itm/Tektronix-2246-100-MHz-4-Channel-Oscilloscope-POWER-TESTED-/322370820559?hash=item4b0ecc59cf:g:ffcAAOSwmLlX9VM7



I am not so interested in 4ch scope and it is big enough. But price is low and may be scope will work, at least 1-2 channels.

 

Or may be Tek 2213A:
http://www.ebay.com/itm/Tektronix-2213A-Analog-Oscilloscope-/201762605727?hash=item2ef9fd0a9f:g:xMAAAOSw-0xYYY15#rwid


I heard that 2213A had a problem with CRT tube.

[Fungus]

Look on this Tek 2246:
http://www.ebay.com/itm/Tektronix-2246-100-MHz-4-Channel-Oscilloscope-POWER-TESTED-/322370820559?hash=item4b0ecc59cf:g:ffcAAOSwmLlX9VM7

How much is shipping to Ukraine? To Spain it's $96

$156 for that? Nope.

[David Hess]

Look on this Tek 2246:

...

I am not so interested in 4ch scope and it is big enough. But price is low and may be scope will work, at least 1-2 channels.

I have a 2246 and a 2247A and they are excellent and reliable oscilloscopes.  We hear about very few problems with them over on the TekScopes@yahoogroups.com email list.  They are also generally newer than the 2225 and 2235 series so suffer from fewer age related problems.

While these are 4 channel oscilloscopes, not all channels are equal.  They really have 2 main channels and 2 auxiliary channels which primarily serve as external trigger inputs that happen to have position controls and 0.1V/div and 0.5V/div sensitivity settings.  The auxiliary channels work great for viewing logic signals.

Or may be Tek 2213A:

...

I heard that 2213A had a problem with CRT tube.

It was the 2213 and 2215 which had CRT problems; the original designs had too high of a heater voltage causing short CRT life.  For that and other reasons, I never recommend the 2213 and 2215 although they can be fine oscilloscopes.

The 2213A and 2215A are cost reduced lower bandwidth versions of the 2235 and came out one year after the 2235 to replace the older 2213 and 2215 designs.

[tautech]

@ David Hess
Just quickly I'd appreciate your comments on the 2465, got my eye on one. 

[David Hess]

@ David Hess
Just quickly I'd appreciate your comments on the 2465, got my eye on one. 

I only recently got a rebuilt 2445B recently so I am hardly an expert on the 2465 series beyond what I have read and discussed on the TekScopes@yahoogroups.com email list.  They are fabulous oscilloscopes but suffer from more problems than the 4 channel 22xx oscilloscopes and have some special issues:

1. The vertical, horizontal, and z-axis DIP hybrids in these oscilloscopes are not as reliable as they should be and if they fail, the only likely replacements are from donor oscilloscopes.
2. Calibration is not trivial and the calibration data is stored in non-volatile memory.  This data will be lost if the lithium battery runs dead or the EAROM fails.  This may not be a problem if you do not require high accuracy.
3. Some units have surface mount aluminum electrolytic capacitors which need to be replaced before they leak and damage the printed circuit boards.

If my 2445B had the optional universal timer/counter, then I would use it in place of my 2247A.

[tggzzz]

@ David Hess
Just quickly I'd appreciate your comments on the 2465, got my eye on one. 

I only recently got a rebuilt 2445B so I am hardly an expert on the 2465 series beyond what I read on the TekScopes@yahoogroups.com email list.  They are fabulous oscilloscopes but suffer from more problems than the 4 channel 22xx oscilloscopes and have some special issues:

1. The vertical, horizontal, and z-axis DIP hybrids in these oscilloscopes are not as reliable as they should be and if they fail, the only likely replacements are from donor oscilloscopes.
2. Calibration is not trivial and the calibration data is stored in non-volatile memory.  This data will be lost if the lithium battery runs dead or the EAROM fails.  This may not be a problem if you do not require high accuracy.
3. Some units have surface mount aluminum electrolytic capacitors which need to be replaced before they leak and damage the printed circuit boards.

I have a 2465 and a 2445B. Both had mains suppression capacitors that needed to be replaced (some had cracked); I would expect most scopes to have that syndrome too. They are easy to replace, but it is preferable to do it before they short circuit and a series resistor disappears. Ensure you get the right X/Y ratings. FFI see http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf

[tautech]

1. The vertical, horizontal, and z-axis DIP hybrids in these oscilloscopes are not as reliable as they should be and if they fail, the only likely replacements are from donor oscilloscopes.

Sphere have some of them but they're not cheap. 

2. Calibration is not trivial and the calibration data is stored in non-volatile memory.  This data will be lost if the lithium battery runs dead or the EAROM fails.  This may not be a problem if you do not require high accuracy.

It looks like it's booting OK at present, it shows a raster on the sellers imagery. Would it pass the boot self tests and go on to display a raster if the ROM had failed ?

3. Some units have surface mount aluminum electrolytic capacitors which need to be replaced before they leak and damage the printed circuit boards.

IIRC the problem units can be identified by SN #'s ?
This one's B025093. IIRC the Tek plant can be identified by this too ?

It looks a clean unit with a front cover and hard copy SM too. 
No Tek probes though.     

[tautech]

I have a 2465 and a 2445B. Both had mains suppression capacitors that needed to be replaced (some had cracked); I would expect most scopes to have that syndrome too. They are easy to replace, but it is preferable to do it before they short circuit and a series resistor disappears. Ensure you get the right X/Y ratings. FFI see http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf

Thanks tgg, yeah been there done that on X and Y rated timebombs. 
Scope like these don't come up very often here..........not that really need it but it does seem fairly priced for a 300 MHz 4 ch scope. Like all these better Tek 2xxx scopes the hybrids and the state of the fan is of primary concern when getting a used one. They have a boot and hour counter don't they ?

[tggzzz]

1. The vertical, horizontal, and z-axis DIP hybrids in these oscilloscopes are not as reliable as they should be and if they fail, the only likely replacements are from donor oscilloscopes.

Sphere have some of them but they're not cheap. 

QService also sells them directly and on ebay; some fail more often and are therefore more expensive. I've had zero problems with QService[1]

2. Calibration is not trivial and the calibration data is stored in non-volatile memory.  This data will be lost if the lithium battery runs dead or the EAROM fails.  This may not be a problem if you do not require high accuracy.

It looks like it's booting OK at present, it shows a raster on the sellers imagery. Would it pass the boot self tests and go on to display a raster if the ROM had failed ?

If the calibration EAROM or battery+RAM is corrupt, it will boot and display a self-test error. When I sell my 2445B I will show a picture indicating that all the self-tests have passed. I am not aware of a way of finding how near the battery is to failing.

3. Some units have surface mount aluminum electrolytic capacitors which need to be replaced before they leak and damage the printed circuit boards.

IIRC the problem units can be identified by SN #'s ?
This one's B025093. IIRC the Tek plant can be identified by this too ?

I suspect that the control boards for 24x5 are EAROM and PTH, but 24x5B are SMD and Dallas battery backed RAM. If it mattered, that can be determined from the online free scanned manuals.

[1] unlike an Israeli company p...... where I waited 6 weeks, and they didn't suggest sending one of the others they were advertising as being available. I raised a issue with ebay, the seller issued a refund - and a few days later they told me the shipper had returned the shipment to them, and did I still want it! Hmmm. (By that time I had received one from QService)

[T@ller]

How much is shipping to Ukraine? To Spain it's $96

$156 for that? Nope.

Well. It costs 6$ per each Kg in US->UA direction.
Internal delivery, to shipping company US address, usually costs about 20$. For DSO a bit less.

For example: shipping weight, external delivery costs, total delivery costs:
TEK 2246 - near 12kg - 72$ - 92$
TEK 2225,2235 - 9kg -  54$ - 74$
TEK 2213A - 7kg - 42$ - 62$

DSO Instek GDS-2102 - 4.3kg - 25.8$ - near 45$
DSO Rigol 1102 - 3.5kg - 21$ - near 40 $

To tell the truth TEK 2246 is weight too much. I am not shure...

What I have to say. I expected spending for delivery US->UA about 40-50$. 

[Fungus]

How much is shipping to Ukraine? To Spain it's $96

What I have to say. I expected spending for delivery US->UA about 40-50$.

On eBay the chipping costs are decided by the seller.

They also have to pack it, take it to the post office, etc.

[David Hess]

2. Calibration is not trivial and the calibration data is stored in non-volatile memory.  This data will be lost if the lithium battery runs dead or the EAROM fails.  This may not be a problem if you do not require high accuracy.

It looks like it's booting OK at present, it shows a raster on the sellers imagery. Would it pass the boot self tests and go on to display a raster if the ROM had failed ?

The power on self test will reveal the problem and I think the readout will also draw a bunch of horizontal dots at the bottom of the display if the calibration data is corrupted or missing.

3. Some units have surface mount aluminum electrolytic capacitors which need to be replaced before they leak and damage the printed circuit boards.

IIRC the problem units can be identified by SN #'s ?
This one's B025093. IIRC the Tek plant can be identified by this too ?

It looks a clean unit with a front cover and hard copy SM too. 
No Tek probes though.     

I think the first series, 2445 and 2465, were all through hole so do not suffer from the surface mount aluminum electrolytic problem.  These also use an EAROM which is sort of like an EEPROM for the calibration data.

[tautech]

Thanks for your help David and tgg
On the one i've had my eye on the readout looks a bit fuzzy (not sharp) but the trace OK, I've spotted threads and posts about how to fix the readout clarity.........still studying.
Meanwhile I've been getting up to speed  on 2465's in BravoV's great thread where it seems my fellow Siglent distributor rf-loop has had a lot of experience with 2465's.
https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/

Anyway while I've been pissing around someone's grabbed it and I've missed out, bugger. 
http://www.trademe.co.nz/Browse/Listing.aspx?id=1230265572

Anyway I probably didn't need another scope to add to the boxes of them I have. 

[T@ller]

While I am making decision the 2213A was sold 

David Hess
Thanks for explanation about Tek scopes evolution. Useful. 

[Gyro]

Anyway while I've been pissing around someone's grabbed it and I've missed out, bugger. 

While I am making decision the 2213A was sold 

At last count, this thread had 1032 views. Unfortunately it's on of the downsides these days. 

[T@ller]

While I am making decision the 2213A was sold 

Double shot. 5 x Tek 2246  was sold too... 

[oldway]

I have repaired a lot of oscilloscopes and I have a collection of analog oscilloscopes.

Here are some personal considerations on this subject.

The main advantage of the analog oscilloscope is its simplicity.
At one time, it was sought to sophisticate it and to make it perform functions for which it was not originally conceived as measures of tensions and time with high precision.
These are the analog oscilloscopes with cursors.

We also wanted to combine the advantages of the analog oscilloscope and digital, which produced "ugly little lame ducks" called combiscopes.

Do not waste your time and money with these lame hybrids.

If you want the storage function or if you want to make accurate measurements, buy a digital oscilloscope, there is no match.

The analog oscilloscope is still very useful in various fields, in repair, in low precision measurements on complex periodic analog signals.

What should you buy?

A single oscilloscope, 2 channels, 50Mhz or more.

What are my preferences?

1) Tektronix: 465B or 2235
2) Hameg HM605 or HM1005 (NB: no component tester)
3) HP: 1740A
4) Philips: I do not like very much the Philips oscilloscopes.

[tggzzz]

Sound points, oldway.

Having 465, 475A+DM44, 485, 2445B, 2465, HP1740A, and an Analog Discovery, my preferences would be:

• 485 for digital signal integrity and general purpose use
• Analog Discovery as a storage scope and network/spectrum analyser, with a basic AWG, pattern generator and logic analyser thrown in

If I had to get rid of the 485, then my preference would be the 2465, the 475A and the hp1740a, in that order (due to their bandwidth).

But I have a soft spot for the HP1740A - it is a pleasure to use and easy to disassemble (unlike the 465, 475A, and the calibration RAM in the 24x5Bs)

[nctnico]

I'd get a Tektronix TDS500 or TDS700 series before thinking about getting an even older analog scope. Lots of knowledge and parts available to fix them.

[T@ller]

oldway
Thanks for advice. And to other guys too.

Models which I guess will be good for general purpose and with 50+Mhz bandwith - for me :

Tek 2213A,2215A
Tek 2235
Tek 2225 - interesting model, why it appeared if there were 2213A,2215A in the same specs ?

HP\Agilent 546xxx - quite specific scope, but a bit smaller and in the same price up to 100$

That is all.

Rigol, Instek costs up to 200$
Tek TDS - as I understood is not my choice.

And I dont understand why Tek 4XX so popular. It is older and much heavier.
 

[tggzzz]

And I dont understand why Tek 4XX so popular. It is older and much heavier.

Heavier, but not much heavier. The 465/475 was designed to fit under aircraft seats.

Why are they still popular? Partly because at the time the 465/475/485 were the best scope in that class, so everybody had them and used them, and now has fond memories of them.

Provided they are functional, they continue to work very well and are a delight to use; you don't get any unpleasant surprises. That's not true for many many scopes; in that sense 465/475/485 are an improvement on many of their successors!

When they need repairing, they are relatively easy to repair: the manuals are good, there is a ready supply of spare parts, and many people are happy to pass on hints and tips.

[David Hess]

Models which I guess will be good for general purpose and with 50+Mhz bandwith - for me :

Tek 2213A,2215A
Tek 2235
Tek 2225 - interesting model, why it appeared if there were 2213A,2215A in the same specs ?

There are 3 major series of 2 channel 22xx oscilloscopes:

- 2213 and 2215 - 30pF inputs, 60 MHz maximum.  The early power supply for this series was problematical.  The modified power supply is almost identical to the 2235 series power supply.

- 2235 - 20pF inputs, 100 MHz maximum, improved switching power supply, many models including 2213A, 2215A, 2230, 2232, and 2236.  These replaced the 2213 and 2215.

- 2225 - 25pF inputs, 50 MHz maximum, line frequency transformer isolated switching power supply, 500uV/div sensitivity, single sweep only with no delay.

And I dont understand why Tek 4XX so popular. It is older and much heavier.

Except for the 485, they are easier to maintain because they use linear instead of switching power supplies.

The 454, 454A, 475, 475A, and 485 have higher bandwidth than any of the 22xx oscilloscopes.  The 475, 475A, and 485 may have a brighter and sharper CRT than the 22xx oscilloscopes.

The oldest in this series, the 453, 453A, 454, and 454A have no custom ICs or hybrids.

The 465B and 485 have alternate dual delayed sweep.  Most of the other 4xx oscilloscopes have mixed sweep which is not as useful.

The 50 MHz 455 and 100 MHz 465M are ruggedized models which use an easier to maintain internal arrangement.  Unfortunately they have mixed sweep instead of alternate sweep.

[BravoV]

David, thanks for the insights. 

The 475, 475A, and 485 may have a brighter and sharper CRT than the 22xx oscilloscopes.

Why is that ? Better or different crt ?

The 465B and 485 have alternate dual delayed sweep.  Most of the other 4xx oscilloscopes have mixed sweep which is not as useful.

So in 4xx series, these two are considered to be top models ?