ATTEN ATF20B teardown

[hacklordsniper]

So while I'm building second bench to be able working on two projects at the same i was waiting on eBay to literally steal a programable quad power supply which in the end gone for 140 $ and i over slept it while going to rest few minutes. ARRRGH.

SO while i checked other items from the seller he had an ATF20B for sale. Well i wanted to teardown one of these some time ago. So here it comes today. IT came in inappropriate box simply flying from here to there and smashing itself (China packaging)!. With it you get a BNC cable, BNC to croco cable and user manual in Chinese 

I noticed the unit is very heavy, much more heavy than Rigol DS1052E. It is also little bit biger than Rigol, in my opinion it is too long.

There is a USB port on the front and RS232 on the back, but more about that to follow...

After opening it i notice the circuit board fell of from its holder and happily swinged here and there whole way. It moved so much it even damaged the metal case... Luckily it did not seem damaged. But i must admit inside is a most sexy mains transformer i have seen in very long time!

Fellows with sharper eye will notice a very long push rod for a real mains switch,  Agilent did you see that ?!? The unit works fine, the display is little bit confusing and controls are too. The USB port on the front is fake, you cant store any waveforms on external stick, its not connected anywhere and there is no output for it on the board 

Whatever you wish, please ask because i don't know what to rant more about it 

You can see its brains clearly on the picture so im not going to write them up. You can also notice nicely marked JTAG

[hacklordsniper]

.

[saturation]

Nice, more later as I can study the photos.

I note you have both the Atten and the Rigol 1022, could you compare the two particularly how well the waveforms are generated?  Most importantly, if you can discern any harmonic distortion in the sine wave outputs, the rise time and squareness of the square waves up to the maximum supported frequency.

Thanks a bunch!

[hacklordsniper]

Nice, more later as I can study the photos.

I note you have both the Atten and the Rigol 1022, could you compare the two particularly how well the waveforms are generated?  Most importantly, if you can discern any harmonic distortion in the sine wave outputs, the rise time and squareness of the square waves up to the maximum supported frequency.

Thanks a bunch!

Hello,

i quickly checked both on my Agilent DSO-X when i managed to get it boot

The crap part is that the ATTEN can generate only the sine up to rated 20 MHz and others to 1 MHz. . Rigol DS1052 rise time is at square 1 MHz 19.8 ns, while ATTEN at 1 MHZ 22.8 ns.

The waveforms squareness is almost exactly the same, very nice

[Richard W.]

Pictures of the transformer and the amplifier output stage would be interesting.

What about frequency accuracy?

You can do some lissajous-patterns with both of the signalgenerators. Make some screenshots 

[hacklordsniper]

Pictures of the transformer and the amplifier output stage would be interesting.

What about frequency accuracy?

You can do some lissajous-patterns with both of the signalgenerators. Make some screenshots 

There is no separate output amplifier than what you see on the board. There is only 4 relays on a small PCB soldered on the front BNC.

The Atten outputs 19.98 MHz and 20 MHz and Rigol does not have this error. Rigol is far more accurate than Atten, and Rigol menu is so inituive like your pocket, while Atten is a little bit retarded. I will try to generate some and see what i get, now i need to go to bed because i just came from it to photo this transformer which initiated various complaints from my wife 

However here are the pics of the transformer, pure and i mean pure nerd porn. I never seen anything alike and i really opened alot of equipment in my life.

[saturation]

Thanks a bunch hacklordsniper.

So to sum, sine waves to 20 MHz, but square, triangle etc., waves only to 1 MHz?

Hello,

i quickly checked both on my Agilent DSO-X when i managed to get it boot

The crap part is that the ATTEN can generate only the sine up to rated 20 MHz and others to 1 MHz. . Rigol DS1052 rise time is at square 1 MHz 19.8 ns, while ATTEN at 1 MHZ 22.8 ns.

The waveforms squareness is almost exactly the same, very nice
[/quote]

[hacklordsniper]

Thanks a bunch hacklordsniper.

So to sum, sine waves to 20 MHz, but square, triangle etc., waves only to 1 MHz?

No problems, i need to push all the teardowns quickly since i will be rebuilding my lab so they sometimes lack the information.

Yes, and how retarded is that. CHANNEL A - sine 20 MHz, all other 1 MHz. CHANNEL B - sine 1 MHZ, all other 100 KHz 

[hacklordsniper]

Some fun DSO-X3000, Atten ATF20B, Rigol DG1022

Im sorry i noticed only now my scope date is set wrong 

[saturation]

Nice, your scope really is fast update rate to show Lissajous clearly, reminds me of an analog screen!

[ciccio]

However here are the pics of the transformer, pure and i mean pure nerd porn. I never seen anything alike and i really opened alot of equipment in my life.
[/quote]

This is a rather unusual type of transformer, called R-type, that was invented in Japan by KITAMURA KIDEN Co. ltd. http://www.kitamura-kiden.co.jp/english/products_e.html.
It has a semi toroidal core, made by first winding a variable width steel tape (the width is variable to get a circular cross-section core), then mounting on the core  two split bobbins that are clamped around the core and have small indents on their border (like a gear-weel) that allow them to by rotated by the winding machine.
This construction combine the low flux dispersion and high efficiency of toroids with the automatic fabrication possible with standard EI core.
I've seen making them in a exhibition: the machinery needed for making cores (cutting and winding the steel tape) and windings are impressive... and truly expensive, so only a limited number of manufacturer is equipped for them.

[hacklordsniper]

Nice, your scope really is fast update rate to show Lissajous clearly, reminds me of an analog screen!

n

Im amazed by my dso-x and realy think Agilent did a wonderful job (except some minor flaws). For fun i tried it on DS1052E and as expected got only garbage on the screen

ciccio thank you for claryfing the transformer. i will study the link

[alm]

Yes, and how retarded is that. CHANNEL A - sine 20 MHz, all other 1 MHz. CHANNEL B - sine 1 MHZ, all other 100 KHz 

Think about how the frequency spectrum looks for the various types of signals, and it will start to make more sense. The bandwidth needs to be much larger to generate a 20MHz squarewave with a reasonable fidelity than for a 20MHz sine. Most function generators either are the same or everything starts looking like a sine at the high end of their frequency scale.

[hacklordsniper]

I agree but the Rigol can do all other to 5 MHz and i just wanted to note Rigol is much better unit for the same price.

[Bored@Work]

The Rigol DG1022 does a 20 MHz sine, but is spec'ed to internally use 100 MS/s in ARB mode. And it can do a square wave up to 5 MHz. Now, why should they use a different sampling frequency for the build-in waveforms than for the ARB mode? If they don't, you have a 20:1 frequency ratio for the square wave.

The Atten ATF20B does a 20 MHz sine, and a 1 MHz square wave. That is 20:1, too. Coincidence? Could it be that the Atten internally just uses 20 MS/s, and that's it? Or Atten really messed up the analog part, designing it for 20 MHz, and then someone figured out, uhm, that's not good for square waves?

But if we ignore the Atten rubbish for now, what about the Rigol rubbish? If it does 100 MS/s internally, what prevents one from getting more than a 20 MHz sine out of it? Maybe only the firmware.

[Bored@Work]

I agree but the Rigol can do all other to 5 MHz

No, pulse is limited to 3 MHz, and ramp and triangle are limited to just 150 kHz.

[hacklordsniper]

I agree but the Rigol can do all other to 5 MHz

No, pulse is limited to 3 MHz, and ramp and triangle are limited to just 150 kHz.

Did not test those still, i was coninced that pulse is also up to 5 MHz and ramp and triangle to 3 MHz

[Bored@Work]

150 kHz was from the specs, and what I remembered. I can get my hands on a dreaded DG1022 earliest on Monday and have a look if the specs lie or not. But I rather prefer not having to touch it or any other Rigol gear.

[alm]

But if we ignore the Atten rubbish for now, what about the Rigol rubbish? If it does 100 MS/s internally, what prevents one from getting more than a 20 MHz sine out of it? Maybe only the firmware.

Maybe they screwed up the output filter, so they had to limit the bandwidth to suppress sampling artifacts from the DAC? Haven't felt the need to acquire one either, so unable to test.

[bruce]

I have been following this thread with much interest. This seems to be the only ATF20b in captivity in the U.S., The Optional accessories seem to be a mystery, They are,  RS232, a 7 watt amplifier and a frequency counter.  Pages 26-29 talk about PC control, How does that work if the USB is fake and RS232 is optional? and, according to Goodluckbuy, you can get the ATF20b for $319.00 with free shipping, or the ATF20d for $450.00 U.S. with RS232 and the frequency counter pre-installed??? Does the add on Frequency counter only add the ability to check the external frequency? I couldn't find this info on Atten's web site... I think I want to purchase one of these, AFT20b if I can control it externally. Thanks for the help, Bruce

[hacklordsniper]

Lose intrest please, no need to discuss this trash. I use it sometimes but its the worste piece of gear landed in my lab

[bruce]

Thanks,
 do you like the RIGOL DG1022 any better? I can get the Atten for $319.00 delivered, and the Rigol for $440.00. If you prefer thr Rigol DG1022 is it the specs, the operating procedures, or the reliability?Is Attn in your opinion, a bad brand, (with great transformers)? If none of the above, what function generator in the $300-$450 range that does similar functions, do you like?
Again thanks for your time. It has helped me.

Bruce

[hacklordsniper]

I have the Rigol too and i like it verry much. DG1022 is great and i dont regret even little for buying it. Software is little bit anoyying sometims but you can use Agilent software to create waveforms and store them to usb stick. Atten does not have software and usb is fake, Atten instrument software is full of bugs, idiotic and hard to use and whole instrument is piece of trash. I would reccomend Atten only if it would cost 50-100 $

[bruce]

Thanks,Hacklordsniper,
  I will be ordering the RIGOL DG1022  next week! in my case a lot to learn!

Bruce Meisinger

[hacklordsniper]

Thanks,Hacklordsniper,
  I will be ordering the RIGOL DG1022  next week! in my case a lot to learn!

Bruce Meisinger

No problem.

If you will need any help with the Rigol feel free to ask. Im glad i saved you from Atten!

[Ray]

I bought a ATTEN ATF20B about a year ago. All this time I thought I was just a sub-genius too stupid to use the USB.

I am in the process of writing some control software for the RS232. Is that fake too? I tried sending some control codes to the port today and nothing happens. That part about it being "optional" yet listed in the standard features makes me suspect it could be fake too. Has anyone tried that yet?

I should have bought a Rigal.

[hacklordsniper]

I bought a ATTEN ATF20B about a year ago. All this time I thought I was just a sub-genius too stupid to use the USB.

I am in the process of writing some control software for the RS232. Is that fake too? I tried sending some control codes to the port today and nothing happens. That part about it being "optional" yet listed in the standard features makes me suspect it could be fake too. Has anyone tried that yet?

I should have bought a Rigal.

Hello,

sorry but you bought trash unfortunately. The RS232 does actually have a connection on the board but never tested does it work. Since no software exists i could easily think it does not

[Ray]

HackLordSniper - YOU WERE RIGHT!

Here is some email dialog I had with ATTEN. I Have a ATTEN ADS1102CAL Storage scope and now wonder if the serial port on that is fake also?

Here is the dialog I had regarding the ATTEN ATF20B function generator. Notice how he can't even keep his fake name straight?



To: sales@atten.com.cn
From: Ray


Hi,

I was told the reason that my USB port on the front of my function generator won't work is because it is fake. Is that true?

https://www.eevblog.com/forum/index.php?topic=4299.15

I have tried for days to get the RS-232 port to work on the back and I have failed. Is that fake too?

Part of the reason I purchased this device is the serial ports that were plainly visible in the advertizement. This is false advertizing in the US and a criminal offense if these ports are fake.

Please inform me of what is real and not. I have spent days trying to connect a computer to my function generator with no success.

Sincerely,

Ray




On 1/11/2012 6:38 PM, ATTEN-Samantha wrote:
 Dear Ray,

 Thanks for your email!
 I am sorry for that problem caused you so much times!
 ATF20B have no USB and RS 232 port,we make  the mould with USB since we are going to develop this function.
 If there are any thing I can help you,please feel free to contact me!

 Best Regards!
 Samantha
 Nanjing Glarun-Atten Technology Co., Ltd.
 A-8, 6th Floor, Tanglang Industrial Zone,
 Xili, Nanshan, Shenzhen, 518055, P.R.China.
 Tel: 86-755-61618238
 Fax: 86-755-61618298
 Cell:86-13684945624
 www.attenelectronics.com




Dear Samantha,

Let me get this straight, you are telling me that my RS232 port is not connected to anything or does not work?

Ray




On 1/11/2012 7:18 PM, ATTEN-Samantha wrote:
 Dear Ray.

 I am really  sorry that this problem cause you so much, All of  our ATF20B have no  RS232 port and USB . This kind of products need to improve .But ATF20D have it. If you have any problems ,please conntact me freely.

  Best Regards!
Cindy
 Nanjing Glarun-Atten Technology Co., Ltd.
 A-8, 6th Floor, Tanglang Industrial Zone,
 Xili, Nanshan, Shenzhen, 518055, P.R.China.
 Tel: 86-755-61618238
 Fax: 86-755-61618298
 Cell:86-13684945624
 www.attenelectronics.com




Dear Samantha,

This is unbelievable and a gross violation of the consumer protection false advertizing laws in the US. NOWHERE did ATTEN disclose that the ports were fake. In fact, they claimed that the RS232 is standard equipment in the brochure.

I am going to give you an opportunity to make this right or I will follow up with criminal charges and a civil lawsuit. My wife works at one of the biggest law firms in the US and I have spent days writing software and building cables for a port that does not exist. This has cost me plenty of time and frustration.

It is your move. I suggest you make that move carefully.

Most sincerely,

Ray





Dear Ray,
 
Thanks for your reply!
Yes,I Know the breochure indicate RS232 Port,that writes"Optional configurations:RS232 interface",this is for customers options,if they want to add this function,we could also do it,but you will have to pay the cost for it since this is not our standard configurations at this moment,but we will add it to our standard configration in a few months.
We make the mould with that RS232 port since some customer will require to add it,then we don't need to change an new mould.
Pleasing your undersatnding with this!
 
Best Regards!
Samantha
Nanjing Glarun-Atten Technology Co., Ltd.
A-8, 6th Floor, Tanglang Industrial Zone,
Xili, Nanshan, Shenzhen, 518055, P.R.China.
Tel: 86-755-61618238
Fax: 86-755-61618298
Cell:86-13684945624
www.attenelectronics.com




Dear Samantha,

I also bought a ATTEN ADDS 1102CAL oscilloscope. Is the RS232 port on the back of that fake also?

I am in the process of writing test and control software for ATTEN products since that is what I unfortunately chose to buy. I felt that I could also sell the software with some modifications to others and make money. Now I see why there is no software available.

You contradicted yourself when you stated:

All of  our ATF20B have no  RS232 port and USB . This kind of products need to improve .

Now you are lying and that is where our conversation is going to end for now. Here are my next moves:

1. I am going to file a criminal complaint against ATTEN with the Oregon State Attorney general and request a criminal investigation.

2. I am going to request a hearing before a federal judge and request that ATTEN products be barred from entering the US by customs due to a gross criminal violation of consumer protection laws while that investigation is ongoing.

3. I am going to explore a class action lawsuit on behalf of anyone that bought an ATF20B function generator.

4. I am going to file a lawsuit on my own behalf against ATTEN.

I told you to be careful of your next move. You made the mistake of trying to sell me something that you already stole from me. Unlike ATTEN, there products and employees, I do have honor.

And lastly,  I will also be filing a formal complaint with the Chinese Government and requesting criminal charges be bought against ATTEN. Your product brochures and users guide plainly state that the RS232 port is programmable. If you think you are going to get away with stuffing one of your newer circuit boards into a ATF20B case and claiming you made them that way all along when the circuit boards did not exist back then, you are wrong. I was not born yesterday.

I have spent approximately a week of my time which I sell for US $90.00 per hour. That is worth $3600.00 not to mention attorney fees, court costs and and court penalties for false and deceptive advertizing. This is a clear case of criminal fraud and I will proceed with vigor in that pursuit as well.

Trying to sell me something ATTEN stole from me was a mistake. I will post this information on ever equipment forum I find for years to come. Good luck selling your fraudulent products filled with flaws here in the US.

Is my RS232 port in my oscilloscope fake too?

Sincerely,

Ray


So there is in black and white. They lied in the user manual that came on the pocket disk telling me how to program a function generator that can not be accessed by a computer and never would be. Then they lied about "upgrading" it. Then they tried to sell me what I thought I had already bought.

I spent days writing a application in Visual Basic to control com ports and output codes to my ATTEN ATF20B with fake serial ports.

I WILL NEVER STOP TELLING THIS STORY OR WARNING PEOPLE DO NOT BUY ANYTHING FROM ATTEN!


Meanwhile, I plan to do everything I stated. That is how I am. ATTEN is a perfect example of why China is laughed at by the world when they sell their cheap junk outside their country. If it were not for the USA, they would not know what a function generator is since they steal our intellectual property every chance they get. Well at least if they can find someone smart enough to copy it. ATTEN could not even steal very well.

BOYCOTT CHINA!

[hacklordsniper]

Great initiative but simply forget it. I was amazed Atten claimed the unit comes with software on CD before i bought, stinky liars!

[(In)Sanity]

I realize this topic is a bit dead..but I have to chime in.   

The wife bought me one of these devices for Christmas after getting some bad information.   

I have to say it about useless.    For the price I think a route canal would be much more enjoyable.   

It locks up my 2465B scope due to harmonics.  Seriously it locks up the CPU.  Happen many times.
If I set it to 60 Hz sine wave it freaks out every meter I have even the true RMS ones and they can't read the RMS value of the sine wave.   If I add a low pass filter it starts to work.  Lame.
The sweep function is too slow to do any type of Bode plot and appears to have no external trigger output,  also lame.
It doesn't appear to remember the last settings I used,  did I mention lame.
The FM and AM modulation appears to allow me to enter values that don't actually result in an output being generated.
It's possible to enter values that result in frequencies that are not on the display.  For example I managed to get 50 Mhz out of it by setting values to 0.    Weird.   
While the waveform that is a flat signal (DC) appears to be somewhat accurate in it's output the peak to peak is low.   
The frequency is off by about 240 hz on a counter that's calibrated within 1 Hz.   I've also done the WWV beat frequency test to confirm this.
How do you upload waveforms to this thing...ohh wait..you don't.   It's an Arbitrary waveform generator that doesn't. 

Good points....the display is nice.  The buttons are pretty good.   The case is not bad.   Aside from the solder slashed on the side of a trim pot the overall construction appears ok.   The connectors are ok.  The supplied cables are ok.   The box it came in was rugged.   The output waveforms appear ok on the surface.   

I would say,   fire the programmers.   Get the calibration team to do a bit better job and you might have an OK product.  The main issue appears to be software related.   The harmonics can be handled with a bit of filtering.   The solder melted to the side of a trimmer pot is just sad.   The frequency being so far out is as well.

If my wife didn't get it over a month ago before handing it to me I would send it back.    In the words Dave would use...what a piece of shit.   If I didn't have to be slightly PC I would go on an on.

Sorry to bring back the dead...but it needs to be said.  Buy the Rigol which is what I expected her to do.   Sigh.  Now I have to build a sweep generator just to do the tasks I wanted one for in the first place which is tune filters.   

Jeff

[alm]

I realize this topic is a bit dead..but I have to chime in.

More information is always welcome.

It locks up my 2465B scope due to harmonics.  Seriously it locks up the CPU.  Happen many times.

This is the first time I've heard of a signal locking up an analog scope. Is this while using cursors or automated measurements? This is the only time the CPU is actually involved in signal processing, as far as I know.

The harmonics can be handled with a bit of filtering.

Are these harmonics from the DAC clock, or harmonics from the output signal due to horrible distortion somewhere in the output stage? The former suggests insufficient filtering after the DAC, which might be fixable. The latter might require redesigning the output stage.

[(In)Sanity]

It locks up my 2465B scope due to harmonics.  Seriously it locks up the CPU.  Happen many times.

This is the first time I've heard of a signal locking up an analog scope. Is this while using cursors or automated measurements? This is the only time the CPU is actually involved in signal processing, as far as I know.

The trace continues,  the ability to control the scope in any fashion dies due to the CPU being locked.   The scopes analog front end is 100% controlled in every fashion by the CPU.  I've had the 2465BDM for a few years now and never before has it done that.  Within a few minutes of trying the Atten signal generator with both ends 50 ohm terminated via BNC the scopes CPU locked solid.  I had to power cycle the scope,  it happen again shortly after.   I've used the scope many times since without the signal generator and it's not happen.   To be fair I'm not positive what waveform was selected when these lockups occurred.   I'll have to try re reproduce the problem or just wait until next time.   

The harmonics can be handled with a bit of filtering.

Are these harmonics from the DAC clock, or harmonics from the output signal due to horrible distortion somewhere in the output stage? The former suggests insufficient filtering after the DAC, which might be fixable. The latter might require redesigning the output stage.

That's a good question,  the waveforms have a step edge from the 8 bit DAC which is clearly visible if you change the vertical scale enough to see the details.   I suspect the harmonics to be at higher frequencies.  I have a couple SDR radio's that I can use as a makeshift spectrum analyzer to see where these harmonics fall.   The meters act as if I'm trying to get them to measure RF rather then the 60 Hz sine wave I have the signal generator producing.   I would be curious if anyone else has this issue.   I may decide to add a low pass filter to the output stage internally and just re-adjust the output trim pots.   It's not in cal as it stands now anyway.   

Thanks,

Jeff

[nctnico]

I realize this topic is a bit dead..but I have to chime in.   

The wife bought me one of these devices for Christmas after getting some bad information.   

I have to say it about useless.    For the price I think a route canal would be much more enjoyable.   

It locks up my 2465B scope due to harmonics.  Seriously it locks up the CPU.  Happen many times.

The latter is probably an issue in your (very old) scope. No matter what kind of signal is presented it should cause a scope to stop working. About the ATF20B... just return it and get your money back. IMHO the Siglent SDG1000 series generators aren't bad. Lecroy sells them under their own brand name.

[(In)Sanity]

I realize this topic is a bit dead..but I have to chime in.   

The wife bought me one of these devices for Christmas after getting some bad information.   

I have to say it about useless.    For the price I think a route canal would be much more enjoyable.   

It locks up my 2465B scope due to harmonics.  Seriously it locks up the CPU.  Happen many times.

The latter is probably an issue in your (very old) scope. No matter what kind of signal is presented it should cause a scope to stop working. About the ATF20B... just return it and get your money back. IMHO the Siglent SDG1000 series generators aren't bad. Lecroy sells them under their own brand name.

So I'll tell the wife she screwed up royally and bought me a piece of junk and that she should contact the ebay seller after over a month and demand a return     That'll go over well.   

I think you'll find enough people who will not blame the scope for obvious issues with the signal generator.   The 2465BDM is still to this day a very capable and useful scope and has never had any issues.   I also have an HP 54111D 500 Mhz DSO that I got for less then the cost of a 50 Mhz Rigol.   I'll get an Agilent 3000 series in time,  but not at the moment. 

[nctnico]

In my experience even Tektronix scopes can develop subtile problems so be warned... Your 2465 must be 25 to 30 years old now. Did you ever check whether the eproms still have the proper software? Is the RAM still working? It sounds to me the signal generator accidentally hit a piece of software or memory area which isn't working properly any more. At some point trusty old equipment gets flaky and ready for the bin.

[alm]

The trace continues,  the ability to control the scope in any fashion dies due to the CPU being locked.   The scopes analog front end is 100% controlled in every fashion by the CPU.  I've had the 2465BDM for a few years now and never before has it done that.

The analog front-end is controlled by the CPU, but the CPU does not digitize the waveform (except that it uses the trigger comparator for cursors and automated measurements). It merely controls the various voltages with DACs. That's why I'm surprised that it chokes on a signal. If it would have been a DSO I would have assumed it to be a software bug in the scope. About the only thing I can imagine happening in the 2465 is noise leaking into the digital circuit, although I haven't studied the schematics in any detail. That would suggest bad circuit design (which I would consider unlikely) or marginal decoupling caps.

[(In)Sanity]

The trace continues,  the ability to control the scope in any fashion dies due to the CPU being locked.   The scopes analog front end is 100% controlled in every fashion by the CPU.  I've had the 2465BDM for a few years now and never before has it done that.

The analog front-end is controlled by the CPU, but the CPU does not digitize the waveform (except that it uses the trigger comparator for cursors and automated measurements). It merely controls the various voltages with DACs. That's why I'm surprised that it chokes on a signal. If it would have been a DSO I would have assumed it to be a software bug in the scope. About the only thing I can imagine happening in the 2465 is noise leaking into the digital circuit, although I haven't studied the schematics in any detail. That would suggest bad circuit design (which I would consider unlikely) or marginal decoupling caps.

The analog portion continues to work perfectly,  with the CPU locked up it no longer has the ability to change values,  etc.   Surprisingly whatever mechanism is cycling the 12 bit DAC and updating all the sample and holds for the analog portions continues to function.   

The right harmonics at just the right combination can cause issues.   Put an iPhone next to the right transmitter and you can brick it,  just an example.    We all know RF can sometimes causes odd behaviors on various circuits and leak in to areas that are not expected.   The sig gen is sitting on top of the scope,  so perhaps the signal is entering in a different fashion.   The scope was built around '93 and is in mint condition inside and out.   It was a very expensive piece of gear when new built by a highly reputable company.    I don't think I can say the same about the sig gen.   

I'm pretty much stuck with the sig gen for now,  so I would rather figure out what's going wrong rather then put blame on equipment that's never had an issue.   The fact that it also freaks out the meters is just more evidence that something is not right.  I've not known other signal generators to freak out multimeters when set to a 60hz sine wave.   

I'll do more testing to determine what waveform or combination is causing the problem and then change the environment to see if the problem goes away.   Irregardless of issues with the scope all the other shortcomings with the sig gen paint a big enough picture.   

Does anyone know if it can produce an external trigger for sweeps ?     

Thanks,

Jeff

[(In)Sanity]

I just found out something very important about my meter issues.   Turns out the gator to coax cable that was supplied with the device has a center pin which isn't making contact.   I used a different cable and it appears to have solved the problem with freaking out meters.   Makes total sense now that I think about it.   

I did figure out however that the Amplitude control appears to only be 8 bit resolution.   The last digit in certain ranges does nothing on many clicks of the digit.   Pretty misleading. 

Thanks,

Jeff

[aghp]

I realize this topic is a bit dead..but I have to chime in.   

The wife bought me one of these devices for Christmas after getting some bad information.   

I have to say it about useless.    For the price I think a route canal would be much more enjoyable.   

It locks up my 2465B scope due to harmonics.

This is perhaps one of best joke of this year.

I have experience about over 40 year with lot of test gears.
I have repaired test equipments (HP, Tektronix etc) lot of.
I have used, calibrated and repaired  many different Tektronix analog oscilloscopes, including 2200 series and 2400 series. Also I have here 5pcs working or waiting cal Tek2465x
I have never seen issue that signal under test locks or disrupt / interfere Tek 2400 series oscilloscope digital systems. It designed and made for analyzing undefined signals. 

Perhaps there is next who tell that Tektronix old workhorse locks becouse signal and earth oscillating mixing product make interference with  control DAC electrons.

ATF20B can not even theory produce signal what shut down Tek 2465B control logick if signal go to Tek 2465 signal input as long as Tek is in normal working condition. If there come too much power and oscilloscope is in 50 ohm there is also protection circuit for 50 ohm terminator.
Some today toy grade test gears  are perhaps different cases.
I have never seen any professional report about this kind of issue in Tek 2465x
But many kinds of belief get food if something happend in same time.

Random things happend same time do not automatically  mean there is causality but instead, it may feed the superstition.

About ATF20B. I have never tested it in real life. It was near one day that I buy one just for make comparison test example with Rigol or Siglent. But then I find idea...  after I carefully read specs AND some user reports. (but keeping mind that mostly disappointed peoples make noise and satisfied peoples keep silence. But in this case it looks like  it really is just its weight about bullshit)

if I make comparison  example ATF20B and SDG1020  only effect is perhaps that someone may thing that these are competitors.
No, they are not and comparison with this kind of crap may give image that they are some kind of same class.  Also former Hewlett-Packard or Tektronix did not comparison they equipments  to famous american crap Heathkit.  You may imagine why.

With around same price you can get example Rigol low end AWG or step better Siglent SDG1000 series AWG.

[(In)Sanity]

I realize this topic is a bit dead..but I have to chime in.   

The wife bought me one of these devices for Christmas after getting some bad information.   

I have to say it about useless.    For the price I think a route canal would be much more enjoyable.   

It locks up my 2465B scope due to harmonics.

This is perhaps one of best joke of this year.

I have experience about over 40 year with lot of test gears.
I have repaired test equipments (HP, Tektronix etc) lot of.
I have used, calibrated and repaired  many different Tektronix analog oscilloscopes, including 2200 series and 2400 series. Also I have here 5pcs working or waiting cal Tek2465x
I have never seen issue that signal under test locks or disrupt / interfere Tek 2400 series oscilloscope digital systems. It designed and made for analyzing undefined signals. 

Perhaps there is next who tell that Tektronix old workhorse locks becouse signal and earth oscillating mixing product make interference with  control DAC electrons.

I hear ya.  It's never ever done such a thing in the past and has not since.   I even started poking around with a current probe and just a single wire  to see if anything was outside the case.  The only thing I could find was about half a volt of square wave at the display if I recall in the 46khz range or so.    I really suspect it has to be the position of the device sitting on top of the Tek rather then the input.   The bypass caps on the A5 board have all either been replaced or checked.   

I really don't think it's the signal input.   Ground loop maybe,  some type of other influence ..maybe.   I'm not able to reproduce it.   The fact of the matter remains that introducing a new piece of gear had some immediate negative effects multiple times on equipment that has been spot on. 

The meter issue was the biggest joke if you happen to of read my findings on that one.   It's one I should have picked up on sooner,  but you assume certain things with new gear...and of course get bit in the ass doing so.   

Perhaps I can donate it to Goodwill or something for a tax deduction    It's still a useful device,  just not a good choice for the money.   Perhaps I can sneak in an old wavetek or something and call it something different.   I'll purchase an RF signal generator that just so happens to sweep and have different types of waveforms.   Naa I need to get my 3457A off for calibration,  that'll cost enough. 

Thanks,

Jeff 

[BeJay]

Hi Guys,

Sorry to bring up an old thread, but could anyone please tell me what part the output amplifier/(whatever it is) IC is that is circled in red on the attachment? I smoked mine up accidentally when testing an old non-isolated organ amplifier board! It's a long story, but sometimes you just forget to use the iso transformer..... but I digress, I now need to fix my ATF20B

Thanks for any help guys!

Cheers

Bj

[BeJay]

After some close photos, I've worked out the output op-amp is most likely a MCP6022 (10Mhz bandwidth TSSOP) that the ATF20B uses for output on CH1. For some reason it's different to CH2 which still works with it removed. Luckily it still has a nice clean input to this OPAMP which hopefully I can bodge the tracks that burnt off

The only thing is I can't find a 14 pin TSSOP to replace this. Is anyone able to verify I'm on the right track with it being a MCP6022T?

Thanks

Bj

[nctnico]

I clearly see the Texas Instruments logo. I think it may be this one:
http://www.ti.com/lit/ds/symlink/ths6022.pdf

[SeanB]

That does seem to suit the layout better, and is a better driver for a signal generator, capable of a 200mA drive into the 50 ohm load and using 15V supplies.

[BeJay]

 Thanks nctnico, it certainly does look like the one, I didn't notice the TI logo before... and the 10Mhz I was looking at was a bit low for 20Mhz output, but I wasn't sure how they were using it. SeanB is on the money with the layout, as it uses the bottom pad for thermal transfer so it's definitely it.

Thanks so much for your help boys, I'm off to order one now

Cheers

Bj

[(In)Sanity]

Looks like you have already narrowed it down.   Should be the THS6022.   I looked it up when I first got the device to see how badly I could abuse it.   No surprise it failed from an input voltage.   I'm slowly growing use to this device and have had no issues at all since my original episodes.   It wouldn't have been my first choice,  but it was a gift and I'm growing use to it.   I guess I should try the RS232 port as it is physically connected on the board.   If it doesn't work it'll just set me off again..so maybe I should leave well enough alone.

Jeff

[nctnico]

Maybe a modification with a low capacitance suppressor diode and some kind of fuse (a low value 0603 resistor) would be a good idea.

[(In)Sanity]

Maybe a modification with a low capacitance suppressor diode and some kind of fuse (a low value 0603 resistor) would be a good idea.

Perhaps a low voltage MOV might be a cheap trick.  It would need to be an ultra low capacitance model or maybe even an avalanche diode.

Jeff

[BeJay]

I will definitely add some sort of protection, as most of the damage was from it's own rails continuing to burn the op amp after the external voltage was removed. It was literally "a tap with the croc clip" on the input of the faulty amp and then the room was fully of smoke that kept coming out of the ATF20B!

[SeanB]

A 50mA solder in fuse will work. I have a plug in protection unit that is designed for a function generator, which has a built in replaceable fuse to protect the signal source. Also can be used as a interseries adaptor, as you can go to and from BNC, TNC, N and PL359.

[BeJay]

"There I fixed it!" - ok, so there is still a lot of flux on the board, and the bodge wires are a little big, but bugger me it works just like when I bough it... Cheers for the help fellas I'm off to make a protection circuit now

[SeanB]

Low impedance.........

Clean off the flux and it will look like it did straight from the factory.

What are you going to use for protection? A pair of  IDC clips and some 50mA sub miniature wire ended fuses to go in them?

[(In)Sanity]

It's not what it looks like,  it's how it works.   Nice job.

[mbdemello]

Hi!  I created a new topic on  ATF20B, regarding a ATF20B main-board (FPGA) failure and  would like to know if you have some schematics or block diagram of that generator.
Thanks and regards,

Mauricio De Mello

[Solder_Junkie]

I came across this old thread recently and a general lack of info on these cheap Chinese function generators. There have been some on eBay UK for £188.77 inc tax and delivery (from a UK address). The price is as low as it gets...

Attached is the English manual for these, if it's of use to anyone considering one.