Tec 475 Oscilloscope questions

BillB3857

Joined Feb 28, 2009
2,571
I simulated the problem by adding two traces, one on the calibration signal and the other touching my finger. It is really strange that your tops and bottoms are fuzzy. Have you tried looking at any other signals? I'm having a hard time trying to think of something for you to look at other than the calibrator.
Almost any digital electronic device will have some nice square waveforms for you to play with. Make sure you have the ground lead from either the scope itself or the prob attached to the power common on whatever you look at. (Hopefully battery powered)

One other thought...... Is there an internal or external astigmatism control on your scope? I assume you have downloaded the manual mentioned earlier. Astigmatism will cause a fuzzy appearance but on the entire waveform. Since the transitions on the cal signal are so fast, it may not show up.
 

BillB3857

Joined Feb 28, 2009
2,571
Spinnaker,

In one of your earlier posts, you mentioned the XY position on your horizontal control. It will tie Chan 1 to the Horizontal amplifier and Chan 2 to the vertical amplifier. It is useful for checking phase or frequency differences between two signals. The attached shows two sine waves of equal frequency signals that are displaced 90 or 270 electrical degrees from each other.
 

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spinnaker

Joined Oct 29, 2009
7,830
I simulated the problem by adding two traces, one on the calibration signal and the other touching my finger. It is really strange that your tops and bottoms are fuzzy. Have you tried looking at any other signals? I'm having a hard time trying to think of something for you to look at other than the calibrator.
Almost any digital electronic device will have some nice square waveforms for you to play with. Make sure you have the ground lead from either the scope itself or the prob attached to the power common on whatever you look at. (Hopefully battery powered)

One other thought...... Is there an internal or external astigmatism control on your scope? I assume you have downloaded the manual mentioned earlier. Astigmatism will cause a fuzzy appearance but on the entire waveform. Since the transitions on the cal signal are so fast, it may not show up.

Yeah there is an external astigmatism control and I tried adjusting it. No dice.

Remember, I hooked it up to a battery and still see the "fuzzy" line.

Plus channel 2 has no deflection to DC. It appears there is something wrong with the DC Coupling. It might be why I can't get a good square wave out of it.


I am going to email the seller to see what he says. I am going to try to return it.
 
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BillB3857

Joined Feb 28, 2009
2,571
My opinion is that if it is not fully functional, it is DOA. Of course I would need to see the full eBay posting. If he advertised as UNTESTED, then you are probably on your own. In that case DOA would mean that you couldn't even turn it on. Do you have the listing number?
 

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spinnaker

Joined Oct 29, 2009
7,830
My opinion is that if it is not fully functional, it is DOA. Of course I would need to see the full eBay posting. If he advertised as UNTESTED, then you are probably on your own. In that case DOA would mean that you couldn't even turn it on. Do you have the listing number?

The ebay page was auto forwarding but I was able to fool it and capture a PDF.

I would say not as advertised at least.
 

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spinnaker

Joined Oct 29, 2009
7,830
The ebay page was auto forwarding but I was able to fool it and capture a PDF.

I would say not as advertised at least.

Opps forgot to attach it. :)

Yeah I think this thing is DOA. It does not even pass the basic timing check as outlined in the manual. You are supposed to be able to set trigger to Line, push and hold in the trig view and see some peaks representing the line voltage. I do not get a trace at all.
 

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BillB3857

Joined Feb 28, 2009
2,571
The wording could be viewed either way, depending upon the point of view. One thing that I did notice is that the seller has both channels showing on the screen and they don't look too bad. Another thing I noticed is that the top channel is set for DC coupling and the lower is set for AC coupling. If I were the suspicious type, I would think that he knew that channel 2 didn't work on DC.

Have you contacted the seller yet? His answer would be interesting.

PS.. Did you pay with PayPal? If so, you may be able to get some relief since the first line of the description said, "....clean and working." Obviously, it is not working as it should.
 

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spinnaker

Joined Oct 29, 2009
7,830
The wording could be viewed either way, depending upon the point of view. One thing that I did notice is that the seller has both channels showing on the screen and they don't look too bad. Another thing I noticed is that the top channel is set for DC coupling and the lower is set for AC coupling. If I were the suspicious type, I would think that he knew that channel 2 didn't work on DC.

Have you contacted the seller yet? His answer would be interesting.

PS.. Did you pay with PayPal? If so, you may be able to get some relief since the first line of the description said, "....clean and working." Obviously, it is not working as it should.

Good catch on the coupling setting!

You are indeed suspicious! :) Good ammunition for a complaint should it go to the PayPal level. I am glad I captured it on a PDF.


Yes I did pay though PayPal. How does that work?


I emailed him. But have not heard back. Last time I asked a question, I did not get an immediate response, so I am not worried yet.

He has a 100% rating with lots of sales so I would hope he would not want a negative comment on an otherwise unblemished record.


It is a real shame. I like the scope. I really wish it was working. I really wanted to keep it, but right now it is junk.
 

BillB3857

Joined Feb 28, 2009
2,571
Yes I did pay though PayPal. How does that work?
I'm not sure how a PayPal claim works since I've never had to make one. If you look at your pdf, you will see their remark about being protected. Log into PayPal and look around. I'm sure there is info on their policies and procedures.
 

BillB3857

Joined Feb 28, 2009
2,571
I just looked again at your pdf. It states that you have a 7 day money back but have to pay return shipping. You are well past the 7 days, but may be able to work something out.
 

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spinnaker

Joined Oct 29, 2009
7,830
I'm not sure how a PayPal claim works since I've never had to make one. If you look at your pdf, you will see their remark about being protected. Log into PayPal and look around. I'm sure there is info on their policies and procedures.
Yeah that is what I am going to do. I figured maybe you had first had info.

Let's hope it does not come to that. I just sent him another email via ebay so there is a record. He gave 7 days to return it. Again a matter of opinion what that means but I would take it as 7 days to express your intent to return. It took 7 days just to get it here.

I got it last Monday so I am right on the button for 7 days. I explained I wanted to make sure it was truly not functioning correctly as I really wanted to keep the scope.

I will post back once I know more.


You think I should mention what you noticed should he give me grief either on the time limit or the meaning of DOA?
 

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spinnaker

Joined Oct 29, 2009
7,830
I just looked again at your pdf. It states that you have a 7 day money back but have to pay return shipping. You are well past the 7 days, but may be able to work something out.
I am right at 7 as I explained above. That could not include shipping, it would not be possible to it back in time. I already told him I would pay for return shipping. I might even eat the shipping to me and consider it a lesson learned.
 

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spinnaker

Joined Oct 29, 2009
7,830
Heard from the seller. He gave me no problem at all. He will take back the scope!


:)

Well I'm out $30 for shipping but much better than the alternative.
 

BillB3857

Joined Feb 28, 2009
2,571
F A N T A S T I C ! ! !

I see that he has another scope up for sale at about the same price. This one has a digital volt meter on top.
 

BillB3857

Joined Feb 28, 2009
2,571
Personally, I would. Based upon his 100% satisfaction record and the fact that he is accepting a return of your unit. Sometimes I get a little over suspicious. Read some of the feedback on him and then decide.
 

VoodooMojo

Joined Nov 28, 2009
505
I suppose mine is slightly different, but it's in the same series of equipment. I certainly wouldn't mind a "smaller" scope, if you know what I mean.

Austin
my main scope now is a Pico 5203. That and a beat up CF-29 toughbook is about all I run with in the field.

I recently soldered up a Velleman PCSU1000 kit for a grandson a few weeks back. Nice unit for what it is.

the 7704 is a mainstay, on the bench almost always on, with a bushel of plug ins.

I collect, restore, and give out to aspiring youth old scopes with new life.
The old Eico 460s are still a hit. Hard to believe.

Digi-Key loves me. A million capacitors later!
 

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