Can you please help me narrow down between these used oscopes?

[Gtr0]

Hi Folks.

Not sure where to post this, but here goes.

Well, after staring at my non-tracing Tektronix 475 for a few months, opening it up several times trying to find something burned or obviously in need of replacement, I need to accept that I can not troubleshoot something this complex. I used it twice, both times successfully. Then I didn't use it for a few months and one day it just stopped giving me a trace.

Time to move on, I need to progress.

As much as I hate buying from ebay (such was the case with my 475), I don't have much of a choice - I can't justify spending a lot of money on a scope that I would use for myself, just because i want to learn about it and build/troubleshoot my amps properly. So I am looking to stay under 300 Euros. Obviously for that price there are absolutely no guarantees. Which really sucks... but it is another reason I can't buy something expensive, unless it were new.

Anyway sorry for the long text - just releasing some frustration :-)

So I have compiled a list over the last week on oscopes on the Bay. I am not opposed to buying something new, but under 400 Euros would I find something useable and reliable? I don't really care about bells and whistles, just want to trace the amp, and I do want to be able to hook up to the plates - so whatever I end up with, I will pick up at least a 100:1 probe of decent quality - knowing that could also be expensive.


1. Tek 2445A - this is preferred as it is the ONLY seller in my budget actually showing the oscope in action with real measurements. It's a bid and will be some days before it is over.
2. Tek TDS1002
3. Tek 2430A
4. Hameg HM-2036 - it has fancy graphics, it must work great [rolleyes].
5. there are a few new options, such as UNI-T UTD2025CL - there are lots of options in this category, names I am not familiar with.

Then there is also the option of getting and older one again, perhaps another 475 and I can use my current one for spare parts if needed.

Could someone please offer some advice here? I have been spinning around on this for a month and a half now. :-(

Thank you in advance for your opinions, experience, wisdom etc!

[glebert]

Scopes are one area that I would never go back to analog. I still have an old tube scope, but my Tek TDS420a is used almost exclusively. I guess I don't see much of a problem with the scopes displaying square and sine waves as opposed to a crappy looking triangularish wave (which to me is more suspect than reassuring).

[Chuck H]

I got mine (BK 2522A) off *bay in the original box and with the original probes and manual. It was carefully used and said to have been calibrated, but that claim is hard to substantiate. The original box showed obvious signs of having been kicked around a little in whatever warehouse it was stored in, but it was there! My guess is that it was a bench tool in a professional environment and sold when they upgraded. But that's only a guess. I can't remember what it cost but it was less than $200 (USD). I shopped carefully for only about two weeks before landing it. I've had it for many years now with no problems.

Things I considered when shopping...

I knew I didn't need high MHZ because I'm only ever going to use this on an amp design/repair bench. I went into it intending to buy used. So those were my way to save $$$. I looked for things like original probes which can be a good indicator that the unit was treated well. As is the original manual. I never expected the original box though. I looked for info about calibration or refurbish. If I had gone with a refurbished unit I would have wanted to see an indication that it was done by a professional shop. And that's about it with the exception that there were things I was looking to avoid...

No probes, no buy. Missing probes could mean the unit was replaced and the probes were put on the replacement. Which could mean someone replaced one used unit with another. Why? I don't want the one they're getting rid of. Or it could mean that whatever probes were used on the unit are lost or busted. Which could mean that it was ill used.

Nothing untested. Calibration wasn't a concern if the unit was shown to be working for basic functions. And honestly, for most of the work I'll do with it super tight, finite accuracy isn't a huge concern. Plus, you can get calibration instruction for most scopes on line. It's never as hard as you think.

Basically I was looking for a scope that didn't need to be anything greater than what I needed. No 150 mHz scopes. Avoid things like "untested" or "as is - no returns" "no power cord" "rouge scope with no history from unknown origins" and "may be possessed by Satan"

Unless you NEED higher functions like ultra wide bandwidth you're looking for a mid line, probably older but respectable used scope with at least an implied good background. That's my point.

[glebert]

Another thing to consider is dynamic range. If the scope has a small dynamic range this can be somewhat manipulated by having multiple probes (1:1, 10:1, 100:1). I had an issue on my digital scope that with a 10:1 probe I could not see the full output range of an oscillating power amp section on a SS bass head. I need to get some 100:1 high voltage probes. That being said, I loved the ability of my scope to see noise down in the 1's of mV when I was hunting for AC noise on an old Vox Scorpion. My tube scope had no chance of seeing that.

[Chuck H]

I really do like the compact footprint on the TDS1002. I've never had a digital scope, but it seems to be the way a lot of professionals here are moving. And I can understand that. Old scopes are sort of enormous by comparison and I've had to grunt mine around a few times.

[TomCarlos]

I have a Tek 2205 Dual Channel Scope. It is old and works. My main scope is an Owon PDS5022S 25 Mhz Dual Channel Digital Scope. It is small, accurate, inexpensive, and certainly does the job for troubleshooting. You can find the PDS5022T for under $250. So my vote is for a small unit, digital, dual channel. I am sure you can find several brands that would fit this profile. Good luck in your search!!

[Gtr0]

Thank you all for the input!!

I too would like a smaller digital version... I had my finger on the trigger for that Tek TDS1002 a few times.... just wanted an opinion there!!! And then after checking out a few Owons, I see this one one ebay Owon SDS1002
20 MHz, 400V max input - both prefect for what I want to do!!

Not a single PDS5022S available in europe.

[Gtr0]

yikes - on second thought that one seems to be coming straight from China even though it says UK... 35 day delivery time... pffffffff

[TomCarlos]

The Owon PDS is an old model. Perhaps you can find something similar - if not Owon, another brand. Something tells me that you have one manufacturer of equipment but sold under several different names. Take a look at Saelig.com. That is where I bought my scope. They sell different brands and I am sure you can find something at or under $250 USD.

[Gtr0]

okay - I took the plunge on the Tek TDS1002. Fingers crossed it all works out. 250€

So I looked up the specs first, 300 v max input... with a 10:1 probe it's good for 3000 volts right? more or less (probably less) Not that I would purposely try to feed it as much, but that should cover me for output tube plate readings right? I wouldn't assume, but I do hope it will do.... ooooor do I absolutely need a minimum 100:1 probe?

BTW...

I got mine (BK 2522A) off *bay in the original box and with the original probes and manual. It was carefully used and said to have been calibrated, but that claim is hard to substantiate. The original box showed obvious signs of having been kicked around a little in whatever warehouse it was stored in, but it was there! My guess is that it was a bench tool in a professional environment and sold when they upgraded. But that's only a guess. I can't remember what it cost but it was less than $200 (USD). I shopped carefully for only about two weeks before landing it. I've had it for many years now with no problems.

Things I considered when shopping...

I knew I didn't need high MHZ because I'm only ever going to use this on an amp design/repair bench. I went into it intending to buy used. So those were my way to save $$$. I looked for things like original probes which can be a good indicator that the unit was treated well. As is the original manual. I never expected the original box though. I looked for info about calibration or refurbish. If I had gone with a refurbished unit I would have wanted to see an indication that it was done by a professional shop. And that's about it with the exception that there were things I was looking to avoid...

No probes, no buy. Missing probes could mean the unit was replaced and the probes were put on the replacement. Which could mean someone replaced one used unit with another. Why? I don't want the one they're getting rid of. Or it could mean that whatever probes were used on the unit are lost or busted. Which could mean that it was ill used.

Nothing untested. Calibration wasn't a concern if the unit was shown to be working for basic functions. And honestly, for most of the work I'll do with it super tight, finite accuracy isn't a huge concern. Plus, you can get calibration instruction for most scopes on line. It's never as hard as you think.

Basically I was looking for a scope that didn't need to be anything greater than what I needed. No 150 mHz scopes. Avoid things like "untested" or "as is - no returns" "no power cord" "rouge scope with no history from unknown origins" and "may be possessed by Satan"

Unless you NEED higher functions like ultra wide bandwidth you're looking for a mid line, probably older but respectable used scope with at least an implied good background. That's my point.

great post - thanks!

[nevetslab]

okay - I took the plunge on the Tek TDS1002. Fingers crossed it all works out. 250€

So I looked up the specs first, 300 v max input... with a 10:1 probe it's good for 3000 volts right? more or less (probably less) Not that I would purposely try to feed it as much, but that should cover me for output tube plate readings right? I wouldn't assume, but I do hope it will do.... ooooor do I absolutely need a minimum 100:1 probe?

BTW...


great post - thanks!

You need to review the specs on the scope probes. Most low-cost X100 scope probes are NOT intended for high voltage, nor can handle high voltage. X100 probes that are good for, say, 1500VDC are NOT cheap. You can find them used, if you spend enough time looking. I have a Tektronix P6009 X100 probe that is good for that range, older style as used with Tek 465's, having the coded pin to shift the sensitivity readout on the display.

[glebert]

okay - I took the plunge on the Tek TDS1002. Fingers crossed it all works out. 250€

So I looked up the specs first, 300 v max input... with a 10:1 probe it's good for 3000 volts right? more or less (probably less) Not that I would purposely try to feed it as much, but that should cover me for output tube plate readings right? I wouldn't assume, but I do hope it will do.... ooooor do I absolutely need a minimum 100:1 probe?

The probes will also have a max voltage spec, which is basically how much power the voltage divider resistors inside can take. Often it is no more than the 300V that the scope input is rated for. Look for probes that are specifically rated for high voltage, I think they are usually rated for 2kV or so. You can find them on ebay.

[glebert]

You need to review the specs on the scope probes. Most low-cost X100 scope probes are NOT intended for high voltage, nor can handle high voltage. X100 probes that are good for, say, 1500VDC are NOT cheap. You can find them used, if you spend enough time looking. I have a Tektronix P6009 X100 probe that is good for that range, older style as used with Tek 465's, having the coded pin to shift the sensitivity readout on the display.

There are cheap x100 probes sold on ebay that claim high voltage rating, but I wonder if they really can handle it? I guess you could test it by "probing" a high voltage source without the probe actually being plugged into the scope.

[Helmholtz]

The probes will also have a max voltage spec, which is basically how much power the voltage divider resistors inside can take.

I don't think resistor power is a concern here. 300V across a 10M resistor or 2kV across a 100M resistor can't be a power issue. Rather these are safety limits regarding isolation, creepage and clearance distances and resistor voltage ratings to prevent leakage and arcing over.

I guess you could test it by "probing" a high voltage source without the probe actually being plugged into the scope.

I don't think so. Safety limits have to take care of worst case environmental and handling conditions (ambient temperature, moistue etc.) I would expect that reputable manufacturers like Tektronics, HP, LeCroy etc. employ standardized design rules and test procedures.

[Gtr0]

I would expect that reputable manufacturers like Tektronics, HP, LeCroy etc. employ standardized design rules and test procedures.

So the plan is to stick with one of these reputable brands... I have a 10:1 tektronix that came with my 475, I will have to look up the model number etc, but it's safe to say that I will probably stick with a Tek brand probe since they seem to be held in high regard... but thank you for the warning that I need to check the probes voltage rating also!!