Author Topic: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator  (Read 76650 times)

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Online Mr. Scram

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #125 on: November 07, 2017, 11:22:08 am »
I ordered mine (30MHz version) from Fasttech, they sell both 30 and 60MHz.
Paid 88$ (~75€), with no shipping fees or taxes added.
Can you look at the jumpers mentioned before? It would be most interesting to see the difference with the 60 MHz version.
 
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Offline Diabolo

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #126 on: November 07, 2017, 11:26:55 am »
Hello,

For FY6600 generators the maximum frequency is valid for the sinusoidal signal, the other signals capping at 20-25 mhz.
The 2 integrated circuits under the aluminum radiator are 4558.
The crystal quartz reference for the Altera Cyclone FPGA is still 50 mhz in FY 6600 and FY2300H.

Dear are you sure the IC is 4558?  |O

device has a 1.7 V/?s slew rate
Unity-Gain Bandwidth: 3 MHz Typ
8 nV/?Hz Typ at 1 kHz

The device is a dual general-purpose operational amplifier, with each half electrically similar to the ?A741, except that offset null capability is not provided.
this amplifier ideal for voltage-follower applications. The device is short-circuit protected, and the internal frequency compensation ensures stability without external components.

Hello,
On FY2300H 25 mhz they are MC4558 under the aluminum radiator, I looked.

Regards.
 
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Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #127 on: November 07, 2017, 01:37:15 pm »
I ordered mine (30MHz version) from Fasttech, they sell both 30 and 60MHz.
Paid 88$ (~75€), with no shipping fees or taxes added.
Can you look at the jumpers mentioned before? It would be most interesting to see the difference with the 60 MHz version.

I followed one of the traces, and its not a setting, but routing the VCO BNC connector to a different trace.
So that is why they are in pairs with one connected (scratchable) and one not connectedd.
Either the BNC plug is connected to one, or to another trace.

I believe something similar is true for the other pair, but something with USB/serial.

IOW, nothing to do with frequency models.
As stated, it would have been too easy if that was how it worked.

So if you want the 60MHz, just shell out an extra $20  :)
 

Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #128 on: November 07, 2017, 02:38:03 pm »
Hi all,

so I wasn't going to join up but I kept reading posts and watching some great videos from some slightly mad nerd and here I am  ;D

I have just taken delivery of a 30Mhz version Firmware 3.1 which as mentioned here already has an issue with a fairly unhealthy floating AC issue. To go with the ugly it is also very accurate in most other things.

It also has an issue with the DC offset having a consistently increasing error that appears to be firmware/maths related. 'Apparently' according to Feeltech this can be and has been fixed with more recent firmware upgrades but as that means shipping a newly delivered unit to mainland China and back it really isn't worth it.   :-- 

Trying to protect their software IP is I guess the major reason rather than enabling a simple programming header or upload system. If that is the reason then it is a poor one plenty of people out there love a challenge  :-+

First problem as discussed in this thread getting the ac floating voltage down. I was just going to drop an IEC socket in but changed my mind as there is plenty of case room for maybe fitting something else into the box as my electronics space is limited due to other toys. So Switch/Fuse and Socket adapter installed instead.

A quick check around the board, jacks and other metal plugs sees the USB case and all the BNC's sharing a common
 AC floating neutral. So like others I am far from happy plugging it into or onto gear until this is reduced.

Few components to add but the coffee needs roasting (part of what I do)
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Online Mr. Scram

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #129 on: November 07, 2017, 03:20:42 pm »
Could you check the aforementioned jumpers?
 

Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #130 on: November 07, 2017, 03:54:53 pm »
I am assuming you mean the jumper from the power supply to main board?

All the terminals (including internal ground) are currently sitting at 32Vac at 50hz. I will be able to spend some more time looking at the board later.

Edit

went back a page. Gather you were now referring to the board jumbers J6, J10-12. They are the same settings as previously mentioned on mine.

2nd edit.

This makes for some interesting reading on the power supply design. http://www.eevblog.com/forum/projects/rm6203-switching-psu-controller/
« Last Edit: November 07, 2017, 05:10:07 pm by beanflying »
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Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #131 on: November 07, 2017, 06:04:03 pm »
I am assuming you mean the jumper from the power supply to main board?

Actually, I find the question on what "leakage voltage" you measure on the supply lines and/or BNC ground also interesting.
And maybe also how much the leakage voltage drops when grounding with a 1M, 100K, 1K resistor to ground. (iow, how current much the leakage can actually source)

As to your "where does the yellow one go" picture title? Is that a question?

If so, I saw someone claim that the 3 holes on the power board, shown pretty just below much dead-centre on your "Feeltech-stock.jpg" image, are ground connections.

And this guy suggests maybe in stead of directly grounding it, using a Y cap. Maybe even a switch and a Y cap, so you can choose whether you want floating or fixed.
« Last Edit: November 07, 2017, 06:06:38 pm by cybermaus »
 

Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #132 on: November 07, 2017, 06:12:34 pm »
Based on a little reading on Class Y leakage and the RM6203 I am leaning toward connecting a 10nF cap from the secondary to earth. The idea of a hard switched internal ground to earth is an easy answer but it then places some operational limits on the device.

I do have an order to put into E14 in the next few days so I am going to add some 'proper' Class Y caps and swap out the current one and see if that helps too.

Fall back is to dump the cheapo power supply and fit a better one  :horse:

Just checked the underside of the board. Of the 3 holes in the pic the two outside are indeed connected to the virtual ground, the centre one has no copper around it.
« Last Edit: November 07, 2017, 06:17:17 pm by beanflying »
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Offline maddin

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #133 on: November 08, 2017, 06:33:52 am »
I found this interesting infos regarding Y capacitor:

https://electronics.stackexchange.com/questions/216959/what-does-the-y-capacitor-in-a-smps-do

If you don't like hard switche internal ground to earth the guy suggested using two capacitors, one from the output to mains earth and one from mains earth to the input.
Maybe the best way also for the FY6600. Anybody tried this solution ? What capacitors were used ?

Regards
« Last Edit: November 08, 2017, 06:35:51 am by maddin »
 

Offline wilhe_jo

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #134 on: November 08, 2017, 06:47:57 am »
For all of you searching for the CD contents....

http://www.feeltech.net/html/list_6.htm brings you to http://www.feeltech.net/html/show_71.htm which lets you download the RAR archive :)

vy 73
 
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Offline maddin

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #135 on: November 08, 2017, 07:39:02 am »
Included FY6600 PC Software V5.3.exe seems also be improved; no virus found  :D
 
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Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #136 on: November 08, 2017, 09:58:36 am »
10nF cap to from the secondary side of the Y cap to mains earth.

Result is a much better 9V at 50hZ. Some more playing needed but first COFFEE  :-+
« Last Edit: November 08, 2017, 10:03:08 am by beanflying »
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Offline battlecoder

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #137 on: November 08, 2017, 10:16:08 am »
After stalking the forums for a few days I decided to join the community.
Initially to thank all of you for sharing your tests and research on this device.

I think I'll be ordering one this week, and will try to contribute to this thread as soon as I get mine.
 

Offline bitseeker

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #138 on: November 08, 2017, 10:18:07 am »
Welcome to the forum, battlecoder!
Have you been BUSTED lately? You probably have TEA.
 
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Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #139 on: November 08, 2017, 12:24:45 pm »
A little bodgetronics later  :o Instrument ground sits at about 3V ac maximum interestingly the Agilent is now reading it at 35kHz (checked on a handheld non rms reads 3.4V)  :-//

There is a little patch of unused board conveniently located right next to the secondaries of the transformer. 2mm screw, shakeproof washer and knurl nut as an earth point. A 10nF ceramic cap and a little heatshrink to each of the transformer secondaries.

Screen of the transient Earth to Virtual Ground below.

Out of ideas or improvements for now. Anyone else suggest an better option?
« Last Edit: November 08, 2017, 02:08:32 pm by beanflying »
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Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #140 on: November 08, 2017, 03:36:22 pm »
Scrapped all but the one Cap from the Y cap to Earth. The transients on the power supply were ugly and while the measured AC was down not a good solution I feel.

So out with my dodgy Hantek. What is interesting is that as soon as it is connected the before measured 7-9V ac all but dissipates. Earth to VG drops straight down to mV as per CH2. This is backed up by the Agilent in terms of DC offset of about -50mV Earth to VG and a spread of AC hash in measured the order of 150mV.

Frequency is bang on on both instruments at 10kHz (10,004 Agilent). Amplitude on the Hantek says 5.2V P-P, Agilent at 1.814 (5.13) for a figure of 5V on the Generator. Waveform looks nice and clean and Symmetrical. (with the single extra cap to earth).

Right now considering looking for a new power supply  :horse:

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Offline battlecoder

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #141 on: November 08, 2017, 03:48:38 pm »
Right now considering looking for a new power supply  :horse:

That seems to be the best way of dealing with this, unfortunately.
Other similar generators from Feeltech have this issue (e.g: The FY3200) and a DIY linear supply seems to be the best way of fixing. I do recall there was a video on youtube showing exactly this.
EDIT:
 

Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #142 on: November 08, 2017, 04:56:08 pm »
Linear makes lots of sense.  :palm:

Dropped a 100k Bleeder Resistor from VG to Earth 2.5V ac and virtually nil DC as to be expected. Tried 500k and 1M but not much of a drop in AC. For reading Good enough for Keysight then good enough for Feeltech  :horse: http://powersupply.blogs.keysight.com/2014/11/why-do-i-measure-voltage-to-earth.html

Back at this sort of voltage should make it safe for 'most' uses and users. Certainly a lot better than the garbage without it.

For my own use I am fairly happy now at this as when loaded with my just the DSO and bleeder/cap it drops way below these figures at 15mV AC and -50mV dc. Most likely won't look at a new supply at this stage.

***** Earth to VG is now at 20mV/div
« Last Edit: November 08, 2017, 05:16:13 pm by beanflying »
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Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #143 on: November 08, 2017, 05:47:34 pm »
I was about to suggest you are overenginering, and should check what it can source and/or add a resistor, when I got notification of a new post.

Linear makes lots of sense.  :palm:

I don't know man. Did you see on the video that even with Linear he also still has an AC leakage of 12V Thats much more than what you have right now, despite his linear supply.

I think what you have now is a very good balance between simplistic and effective, and I will copy it.
The only think I might try is a 1M resister instead of a 100K, you said you tried but I did not quite understood the result.

I am not at home right now, otherwise I would be testing myself.  This thread seems to make it all very important, but I just did not pay attention before and everything seems to work. That is why I think that the 'floating' cannot really source any current, and we are being oversensitive.
 

Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #144 on: November 08, 2017, 06:01:53 pm »
I guess I have fried and seen enough things fried by ordinary design and attention to detail over the years. Haven't watched the video yet either.

Apart from a new supply it was always just a matter of 'some' filtering on the basis it is never going to be perfect but just where and what needed some educated blind guesswork. Given the bad start point and the low cost to big improvement well worth it for anyone with this supply. I will still fit up a different Y cap when they arrive.

Let us know what you find with the 1M, I have put the lid back on mine for now and will use it as is and have a proper play.  8)
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Offline battlecoder

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #145 on: November 08, 2017, 06:20:54 pm »
I don't know man. Did you see on the video that even with Linear he also still has an AC leakage of 12V Thats much more than what you have right now, despite his linear supply.

I think what you have now is a very good balance between simplistic and effective, and I will copy it.
The only think I might try is a 1M resister instead of a 100K, you said you tried but I did not quite understood the result.

I am not at home right now, otherwise I would be testing myself.  This thread seems to make it all very important, but I just did not pay attention before and everything seems to work. That is why I think that the 'floating' cannot really source any current, and we are being oversensitive.
In defense of the mod suggested on the video, it was 12VAC but virtually 0 current (below 1 uA, apparently).

Anyway, I suspect that the optimal (or "good enough" solution) will be different for every user, depending on what they will be using the device for, and whatever lets them sleep at night.
For instance, I'll most likely follow the steps of beanflying and yourself, and simply use a bleeder resistor, because it's simple and apparently works a treat, but I'm sure a number of users would prefer to ditch the switching supply entirely and put a linear one in there.

I still hope that the unit I receive will not leak badly. It happened with the FY3200 that users were getting different voltage and current values for the "leak" (probably different hardware revisions, but could also be related to the difference in mains voltage and frequency between countries).
I guess it's like they say: "Your leakage may vary".
 

Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #146 on: November 08, 2017, 09:47:03 pm »
It happened with the FY3200 that users were getting different voltage and...

Well, it also depends on your measuring equipment. Using 240V mains base (UK), measuring a 12V AC signal with a DMM that has a 10M impedance would imply a "leakage" of 200MOhm (ok, 190M), either restive or reactive. And there will always be some capacitance, so some reactive impedance.
Someone else measuring the exact same device with a DMM of 1M impedance would find 1.2V

... and current values for the "leak"

which is thus much more relevant. What current can the "leak" source. I plan to measure it as soon as I get home, but no-one else seemed to have supplied numbers here (maybe I have missed them). Which is why I suggested we should be a little more relaxed before bashing the power supply and adding deceased animal abuse symbols. At the very least until we have leakage current measurements.

Especially because the DC findings from @beanflying suggest a <10mV at 100KOhm measure impedance. Even though that was ground to virtual ground, it does suggest a better then 2400MOhm DC (non reactive, restive, please check my math) impedance on the mains-secondary-virtualground-ground path. 2.4GOhm ! Which if true means quite the opposite of the impression that this thread may be giving people.
 
 

Online Specmaster

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #147 on: November 08, 2017, 10:07:31 pm »
I think that at the end of the day a decent linear power supply would certainly eliminate most of the leakage and if it really was a major concern, then it would not take too much to rig up a battery power pack option to completely remove the leakage to ground and thus the potential difference and problems arising from it? The current draw surely is not going to be that great is it?   
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Offline beanflying

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #148 on: November 08, 2017, 11:44:47 pm »
Nothing essentially wrong with switch mode power supplies. My 8 year old 15V 60A Switch mode Manson still runs at less than 5mV ripple in spite of plenty of kwality Capxom Caps. My Fixed 12V 20A bench supply (Chinese LED driver $25) is under 20mV and the VG on it is under 6V ac but using a little of what I have learned here I will have a look at improving it a bit too.

Dead animal flogging or not the power supply used here can and should be improved as it is sub standard for test equipment. It seems that if the same issue with earlier models has just flowed into this one then without making a little noise will likely see it continue in future production and models.
« Last Edit: November 08, 2017, 11:46:42 pm by beanflying »
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Offline ArthurDent

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #149 on: November 09, 2017, 01:48:52 pm »
After reading some of the other replies I have come up with a plan for the mods I want to try. First I measured the voltages on the stock power supply and measured +4.78, +13.6, and -13.8 which isn’t that close to the +5, +12, and -12 that it should be putting out - certainly not the best supply. Most good SMPS units have an adjustment that trims the +5 and the other two voltages are just kind of a ratio from the +5.00 so they aren’t as close but generally within +/- .2 volt.  Obviously the FY6600 worked with the existing P.S. but I wanted something closer so that meant changing supplies.

 I also wanted to change the timebase which is worse than 100 PPM and 50 Mhz so I figured I’d use a decent square wave 10 Mhz OCXO followed by a 50 Mhz passive bandpass filter to use the 5th harmonic from the square wave but CyberMaus mentioned the NB3N502 PLL IC that I didn’t know about and it looks like the perfect solution.  I didn’t want to incorporate a GPS into the unit (I have several different ones running 24/7) so decided to use an OCXO from a Trimble Thunderbolt that is fast warm-up and very stable. Power required at +12 cold is .7 amp so the existing P.S. wouldn’t have worked anyway. I’ll include a switch on the back panel so if I want to make use of the resolution the FY6600 is capable of at GPS or rubidium accuracy I can feed an external input to the X5 PLL. 

 So I’ve ordered a couple of NB3N502 PLL chips from Mouser that should be here any day now and I can get to removing the 50 MHZ SMD crappy oscillator and Frankenstein the PLL chip on the board in place of the 50 Mhz oscillator and put the OXCO on a small circuit board with a ten-turn pot to trim it on the back panel next to the switch and BNC for my external 10 Mhz reference.
 
 I have already changed power supplies and the one I chose is heftier than needed but is high quality and I had a few new ones I could use. The supply is a NFS40-7608 which is made by several venders and I bought the supplies I have from a surplus catalog at a good price.  So here is a photo of the power supply mounted in the case and working. I had to cut and splice the connector cable but it works as intended and I'll do an update once I get the rest of the modification done.
« Last Edit: November 09, 2017, 11:45:33 pm by ArthurDent »
 
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