FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator

[battlecoder]

I don't have one of these devices, but what does the scope show you with the unit powered off entirely? Is it the same, or does some/all of the measurement clean itself up? Just curious to know if it's actually coming from the unit, or if it's radiated from somewhere else.

It's coming from the unit: I've attached an image of the same setup but with the FY6800 switched off at the mains.

You might try enabling the 20MHz bandwidth limit on the scope to knock some of the noise down if those spurs are giving you trouble with triggering.

Yes, I've tried that but it doesn't really clean things up enough. I'm not sure if this is just something that I have to live with. It's a bit of pity if so, as the device itself can generate sub 10 mV signals, but they're swamped in the SMPS noise.

I tried with my unit and the freerunning waveform shows some peaks of around 30mV. That goes down to around 14mV with 20MHz BW limit.
If I trigger on the spikes, and zoom into the periodic "noise", I'm getting a 10mV, 6-7Khz nonsense.

[beanflying]

Just how are you getting the signal from the Feeltech into your Rigol? It matters!

Some time ago I built a BNC - Probe adapter (can also be brought online) https://www.eevblog.com/forum/beginners/o-scope-probe-to-bnc-adaptor-(dave-uses-on-in-642)-where-to-findbuy/msg2287812/#msg2287812

Fixes a bunch of induced noise source issues compared to incorrectly terminated scope inputs.


Have a trawl through this youtube search too https://www.youtube.com/results?search_query=oscilloscope+termination

[radiolistener]

I've attached an image of the signal that I get from my FY6800, channel 1, with the unit on, but with channel 1 disabled. There's noise at about 44 kHz of about 40 mV pp, which I'm guessing is from the SMPS.

My question is: is noise of this magnitude expected from this unit?

I read that other users also have experienced with such noise from switching power supply. It may leak through ground wire, so it may be  hard to get rid of it. I think the only way is to replace it with linear power supply, but it will require better ventilation in order to cool down power supply.

[aneevuser]

Just how are you getting the signal from the Feeltech into your Rigol? It matters!

I'm not sure how that is relevant to my problem, though.

I'm typically taking the signal to a breadboard with the BNC-croc clip cable provided with the FY6800. However, the noise that I see is present at the BNC connector on the device itself; it's not radiated noise that is picked up by the cable. So I can't see how any different cable would improve the situation (unless there's some kind of fancy filtering on it, and I don't think that you're suggesting that?). Maybe I'm misunderstanding you though.

Anyway, the figure posted earlier by battlecoder suggests that this noise is not untypical, so I guess I'll have to live with it, unless I can figure out how to replace the power supply.

[aneevuser]

I tried with my unit and the freerunning waveform shows some peaks of around 30mV. That goes down to around 14mV with 20MHz BW limit.

Thanks. Not different from what I see. I guess that it's a design problem, rather than a one off quirk of my unit.

If I trigger on the spikes, and zoom into the periodic "noise", I'm getting a 10mV, 6-7Khz nonsense.

Not sure what you mean here - what's the "nonsense"?

[beanflying]

Fairly simple you are blaming the source without considering the measurement tool and the cable leading up to it as the potential problem. Incorrectly terminated transmission lines (not impedance matched) not to mention breadboards SUCK and are as noisy as ......

[radiolistener]

unless I can figure out how to replace the power supply.

Here is experience of one user to replace power supply with linear one. It helps a lot to remove such noise.
It is in russian, but I'm sure you will understand all from pictures.

https://www.nickbel.com/2018/10/05/zamena-bp-na-lineynyy-transformatornyy.html

[aneevuser]

Fairly simple you are blaming the source without considering the measurement tool and the cable leading up to it as the potential problem. Incorrectly terminated transmission lines (not impedance matched) not to mention breadboards SUCK and are as noisy as ......

Well, it's always worth considering alternative explanations but if this were a transmission line problem, would it not be strongly frequency dependent? I see precisely the same noise signature from DC up to 1 MHz. In addition, as I mentioned earlier, it's present directly at the BNC output of the device so the presence of the cable or breadboard is irrelevant.

I'm not convinced this has anything to do with transmission line problems.

[aneevuser]

Here is experience of one user to replace power supply with linear one. It helps a lot to remove such noise.
It is in russian, but I'm sure you will understand all from pictures.

Thanks. Looks useful. My Russian isn't too bad, so with the autogenerated subtitles, I should be able to understand a fair bit of that. I guess that there'll be others on Youtube as well, if this is a known problem with the device.

[CDaniel]

You don't have to know russian , if you have patience to read this thread you will find that for a long time users have replaced that crappy cheap SMPS with a transformer + linear regulators and how they did it .

[beanflying]

For those suffering with blown or broken units this may offer a possible way out FINALLY after some kicking Taken from the spriuking 6900 thread in the For Sale section.

Personally I think their way out should be firmware release but this may at least provide an option better than has been available in the past.

You simply FAIL to comprehend your past. About the only way forward to start to remedy this is release the firmware for the FY6600 and the method to repair damaged units. Either that or consider sending 'review samples of your new one to those affected that have dead units. Return shipping and freighting units is just not on unless YOU are paying for postage both ways.

Both of the member quotes above were from your most recent spruiking of the 6800. And surprise surprise went unanswered.
This Link https://www.eevblog.com/forum/contests/feeltech-fy6800-signal-generator-free-trial/

We have no staff to take charge of this forum account before. We have not landed in this forum for a long time. We apologize for the vacancy in our work. At the same time, we will compensate the damaged customers. From now on, our account is in the charge of a special person, we will maintain the forum. Customers who have purchased version FY6600 V3.0 before will send the firmware chip downloaded version V3.1 free of charge as long as they contact us. At the same time, if these customers intend to purchase FY6900 series products, our company will return all the profits of the machine to customers, charging only the cost of equipment and transportation costs. Please contact us in EVVblog or Email.

Email address: service@feelelec.com

[bitseeker]

Interesting development. Of course, the proof in the pudding is in the eating. So, it's time for all the V3 owners to put FE to the test.

[beanflying]

Interesting development. Of course, the proof in the pudding is in the eating. So, it's time for all the V3 owners to put FE to the test.

I dropped Fremen67 a PM. Offhand I can't recall others with dead or partially dead units but if others do hit them up.

[FeelElec]

Has anyone gotten the firmware update to work with PC Software version 6.0?
My FY6600 has firmware 3.1, PC Software says that the latest available firmware is 3.3, but when I click "update" it seems to download something but then it immediately throws the error "USB linkage fault".

Dear Customers,
3.3 began to add online upgrade function, 3.1 does not support online upgrade.
If you have any problems with version 3.1, please feel free to contact us.

FeelElec

[battlecoder]

Has anyone gotten the firmware update to work with PC Software version 6.0?
My FY6600 has firmware 3.1, PC Software says that the latest available firmware is 3.3, but when I click "update" it seems to download something but then it immediately throws the error "USB linkage fault".

Dear Customers,
3.3 began to add online upgrade function, 3.1 does not support online upgrade.
If you have any problems with version 3.1, please feel free to contact us.

FeelElec

Oh. That's quite unfortunate.
Thanks for the answer, though.
Do you have a changelog of what was updated, changed, or fixed in version 3.3 so I can see what I'm missing?

[Johnny B Good]

Interesting development. Of course, the proof in the pudding is in the eating. So, it's time for all the V3 owners to put FE to the test.

I dropped Fremen67 a PM. Offhand I can't recall others with dead or partially dead units but if others do hit them up.

 His last posting to this thread was back in June last year

https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg1597255/#msg1597255

 and he hasn't been heard from since. A few have expressed concerns over his sudden disappearance in the middle of answering questions and providing feedback, fearing the worst for his health and well being. If you do hear from him, I'm sure many others here will appreciate any further news you might glean from this recent PM attempt. I believe others tried to PM him but without reply. Hopefully, you might strike lucky this time.

JBG

[FeelElec]

Oh. That's quite unfortunate.
Thanks for the answer, though.
Do you have a changelog of what was updated, changed, or fixed in version 3.3 so I can see what I'm missing?

Dear Customers:
This is the answer: 3.3 Added offline upgrade firmware function, other functions are consistent with 3.1.

FeelElec

[MikeLud]

I need some help with my FY6800 power supply upgrade. I did most of the upgrades shown in this schematic https://github.com/DerKammi/FY6600-15-30-50-60M/blob/master/Hardware/FY6600%20PS%20schematic%20V1.pdf. The only difference is I did not change D9 and instead of changing R6 I replaced the two 10K voltage divider with a 20K Multiturn Trim Pot wire the same as a voltage divider so I can adjust the output voltage. Also instead of using a 68uF 400V for C2 I used a 33uf 400V. Now the FY6800 intermittently turns on by having to turn it on and then off several times using the switch in the back. When it does turn on it works fine, with the power supply voltage at -13.6V, +13.5V, and +5.0V. and the on/off button in the front work fine as long as I do not turn it off with the back switch. Any help will be appreciated.

Thanks,
Mike

[CDaniel]

I don't think that power supply is worth upgrating , just replaced with a linear one .
Anyway you should measure your pot resistance and see if  it works ok with the old value 10k , in a such SMPS you can't change the voltage by much or could become unstable . Even if it's 12K as the autor say it works , because of various tolerances is not certain that in every case  will work

[FeelElec]

I need some help with my FY6800 power supply upgrade. I did most of the upgrades shown in this schematic https://github.com/DerKammi/FY6600-15-30-50-60M/blob/master/Hardware/FY6600%20PS%20schematic%20V1.pdf. The only difference is I did not change D9 and instead of changing R6 I replaced the two 10K voltage divider with a 20K Multiturn Trim Pot wire the same as a voltage divider so I can adjust the output voltage. Also instead of using a 68uF 400V for C2 I used a 33uf 400V. Now the FY6800 intermittently turns on by having to turn it on and then off several times using the switch in the back. When it does turn on it works fine, with the power supply voltage at -13.6V, +13.5V, and +5.0V. and the on/off button in the front work fine as long as I do not turn it off with the back switch. Any help will be appreciated.

Thanks,
Mike

Dear Customers:

If you want to cut off 220V power supply, you can only turn off the power switch in the back. It is not recommended to change the power parameters. Replacing linear power supply can reduce the noise of small signal.

FeelElec

[Johnny B Good]

I need some help with my FY6800 power supply upgrade. I did most of the upgrades shown in this schematic https://github.com/DerKammi/FY6600-15-30-50-60M/blob/master/Hardware/FY6600%20PS%20schematic%20V1.pdf. The only difference is I did not change D9 and instead of changing R6 I replaced the two 10K voltage divider with a 20K Multiturn Trim Pot wire the same as a voltage divider so I can adjust the output voltage. Also instead of using a 68uF 400V for C2 I used a 33uf 400V. Now the FY6800 intermittently turns on by having to turn it on and then off several times using the switch in the back. When it does turn on it works fine, with the power supply voltage at -13.6V, +13.5V, and +5.0V. and the on/off button in the front work fine as long as I do not turn it off with the back switch. Any help will be appreciated.

Thanks,
Mike

 Hi Mike, and welcome to the FY66/68 hundred modders' house of fun and pains.

 I had several criticism regarding those modifications when I looked them over for inspiration on 'improving' the PSU board in my then newly acquired FY6600-60M way back in November last year just before I made my very first post to this forum. I've inserted a link so you can see my initial modifications to the PSU board (I've lost count of the all the other mods I've tried with that PSU since then).

https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg1973777/#msg1973777

 For starters, the value of the mains smoothing cap was over-specified by almost a factor of seven. The original 10μF 450v is entirely adequate for a 10W rated smpsu designed to operate on mains voltages in the 86 to 365 vac range (1μF per watt appears to be based on a universal design rule for all such universal mains voltage smpsus - I've yet to come across any exceptions to this 1μF per rated watt rule).

 If you're only using it on 220v or 240v mains supplies (the harmonised 230v mains specification in all its guises of practical reality) without any thoughts of ever using it on 110/120v supplies, there's absolutely nothing to be gained by such an 'upgrade'. Indeed, the reduced voltage rating from 450 to 400 volt of the suggested replacement places the logic of replacing the 220μF 16v caps on the 12v rails with 25v rated 220μF caps in some doubt.

 Whilst the 400v rating is perfectly fine for this task, the voltage rating upgrade on those 16v 220μF caps would equate to increasing a 400v smoothing cap to 625v (or the original 450v cap to a 700v rated one - it makes very little sense when the PSU is operating under its designed conditions (never disconnected from the load whilst powered up for prolonged periods of time) to uprate those output caps to 25v. A far more useful upgrade would be to replace them with 470μF 16v caps - the voltage isn't the issue here (it really isn't - trust me).

 However, when it comes to improving the smoothing on the 5v supply, it can be all too easy to get carried away (replacing the 470μF with an 1800μF 6.3v cap and replacing the 220μF with a 1000μF 6.3v cap) and overload the dinky little high voltage switching IC on startup causing it to sulk in a shutdown standby state. In the end, I landed up reducing these capacitor upgrades in two stages before I could eliminate the hot restart issue that had appeared after I'd cured the cold startup issue. Effectively, I'd dialled back the 1800μF to a mere 1000μF and restored the original 220μF.

 You could say (as indeed someone did) that I'd upgraded it to 'capacity'. If I hadn't already upgraded the 12v rail caps to 470μF ones, I might have gotten away with the 5v rail capacitor upgrade. However, using up my capacity margin on the 12v rails was the best option anyway - less ripple on the analog supplies (all derived off the 12v rails) where it really matters - the 5v rails can go hang, it's only used to power the three LDO regulators anyway (3.3, 2.5 and 1.8 volt rails) on the main board.

 The diode upgrades are a definite requirement to both improve the 12v rail voltages and the efficiency of the PSU (apropos of which, install a small cooling fan if you don't want to be faced with a recapping job in 12 to 18 months time - the vent slots are counterproductive to passive cooling, a small vent fan is an absolute must imho). If you read that first posting of mine, you'll note I went a little overboard on the diode upgrade (well, I had them to hand, so why not already? ).

 Much later on, I'd worked out an optimal solution to increasing the voltages on the 12v rails far more effectively than my 47k 10% boosting bodge on the 5v rail to likewise boost the 12v rails (over and above the extra two turns I'd added to each of the two 12v windings I'd applied in a previous modding session). ebel0410's mofification to the voltage feedback network raised a wry smile by the fact that he'd made more work for himself by removing R6 and replacing it with a 12K rather than use the quicker and slightly more effective shunting of the other 10K in the voltage divider with a 47K to get virtually the exact same result. When it comes to this sort of modding work, there's usually more than one way to skin the cat.

 You can view my description of my final PSU mod here:-

https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg2310768/#msg2310768

 And, you might find this earlier posting of some interest too.

https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg2182397/#msg2182397

 For all its faults (high ripple noise - on a par with any commodity smpsu to be fair), the one thing Feeltech's tiny smpsu board doesn't suffer from is imbalanced current output ratings on its +/-12v rails, unlike every single example of dual rail commodity smpsus I've ever seen on Ebay (whether just a naked PCB or an enclosed unit).

 Looking on Ebay for dual rail smpsus designed to satisfy the requirements of dual rail opamps is on a par with tracking down Unicorn droppings (never mind the Unicorns themselves! )  Typically, such small dual rail smpsus will specify a +12v rated at 600mA whilst the -12v rail is only rated for 150 to 250mA at most, often with the requirement that the +12v be loaded to a minimum level to bring the -12v to within 10% of its nominal voltage spec.

 Mind you, if you happen to be planning on adding a 12v 10MHz OCXO (with a 3N502 clock multiplier chip replacing the shite smd XO chip on the main board), such an imbalanced spec might be just the ticket! 

 Obviously, there are suitable smpsu modules available which have balanced ratings and very low switching noise but you won't find any on Ebay. You have to deal with the manufacturers or their agents directly and put in a request for a quote on pricing and you know what they say about that... "If you have to ask, then you probably can't afford it."

JBG

[MikeLud]

I decided to go with replacing the SMPS with a linear power supply. I found a LM317/LM337 and LM317 linear regulator in country at a reasonable price, below are the links to the ones I will be using. To feed the linear regulators I am going to use a 30W R-Core Transformer 15V+15V 9V+9V.

https://www.parts-express.com/adjustable-voltage-regulator-power-supply-board-----125v-to-37v-dc-output-lm317-lm337-desig--320-616
https://www.parts-express.com/positive-voltage-adjustable-power-supply-board-ac-dc-in-dc-out-based-on-lm317t-regulato--320-614

Thanks,
Mike

[Johnny B Good]

I don't think that power supply is worth upgrating , just replaced with a linear one .
Anyway you should measure your pot resistance and see if  it works ok with the old value 10k , in a such SMPS you can't change the voltage by much or could become unstable . Even if it's 12K as the autor say it works , because of various tolerances is not certain that in every case  will work

 The analogue psu can be an effective solution but the downside is that you'll introduce greater thermal stress than the original (typically 70 to 80% efficient) smpsu board on the unit if you neglect to add a cooling fan to prevent an already hot running generator from overheating. Preferably a fan that offers a further reduction in temperature to extend the life of the components, most notably that of the 105deg C rated caps.

 Indeed, a few of the homebrewed analogue PSU projects have suffered regulator failures for lack of heatsinking, in some cases to the detriment of component failure on the main board (a brand new THS3091 burning out forcing the owner to revert back to the original THS3002i chip for lack of a spare 3091 being one notable event).

 If you're going to build a custom analogue psu, you need to be very mindful of this thermal issue. A fan is a must have item, even before you add the additional heat from an analogue psu, imho. IOW, make adding a cooling fan you first priority before doing anything else (after allowing a period of grace to allow any faults to show up before voiding the Chinese warranty, of course ).

JBG

[MikeLud]

JBG,

Thanks for your advice, I will be adding a cooling fan. Once I finish the PS upgrade I will be upgrading to a D75J and THS3091.

Thanks,

Mike

[CDaniel]

I don't think that power supply is worth upgrating , just replaced with a linear one .
Anyway you should measure your pot resistance and see if  it works ok with the old value 10k , in a such SMPS you can't change the voltage by much or could become unstable . Even if it's 12K as the autor say it works , because of various tolerances is not certain that in every case  will work

 The analogue psu can be an effective solution but the downside is that you'll introduce greater thermal stress than the original (typically 70 to 80% efficient) smpsu board on the unit if you neglect to add a cooling fan to prevent an already hot running generator from overheating. Preferably a fan that offers a further reduction in temperature to extend the life of the components, most notably that of the 105deg C rated caps.

 Indeed, a few of the homebrewed analogue PSU projects have suffered regulator failures for lack of heatsinking, in some cases to the detriment of component failure on the main board (a brand new THS3091 burning out forcing the owner to revert back to the original THS3002i chip for lack of a spare 3091 being one notable event).

 If you're going to build a custom analogue psu, you need to be very mindful of this thermal issue. A fan is a must have item, even before you add the additional heat from an analogue psu, imho. IOW, make adding a cooling fan you first priority before doing anything else (after allowing a period of grace to allow any faults to show up before voiding the Chinese warranty, of course ).

JBG

Yes , I know , or you could build the supply in an external box . Could be easier this way , you don't have to find the right size transformer .
Mine is inside and gets hot , for stand-by I found a signal from the microcontroller in the front display board that's switching a relay so +15V and -15V are disconnected. If not , in stand-by the analog part will still consume a lot of current ... no shut down feature was implemented in the original design .