I have fixed this by putting insulation trasformer in between orignal switching power supply and mains. Just used small 20VA toroidal transformer and wound another 230v winding on it making it a 230/230v insulation transformer. Installed it directly into the generator. Cost me 10€ works great
Yes there is a fair amount of leakage resulting in almost mains voltage on the exposed BNC connectors, but we need to remember this is in the microvolt range, so if you grab the connector, you will not get a jolt of it, there isn't enough current, BUT, it can and will, as stated in the video, destroy sensitive devices such as JFET's and static sensitive devices, processors and things like that.....Thanks for getting the word out there and letting people know about this....
Switch mode power supply has issues because of poor grounding. So beware of this when testing other devices with it. Probably need it plugged into an isolation transformer. Good idea to replace it with a linear style PS.
Did a similar thing to genius3258, installed 2 back to back 240V/9V little transformers between power supply and mains. Also added a switch to select floating / grounded. BTW if you have a basic model (low bandwidth) you can increase this by holding the menu button a specific amount of time while powering on. I added a 8-pin microcontroller that simulates a key press during power-up. By tweaking the delay loop I now have 15Mhz instead of 2 :-)
Scary. If you're going to do the power supply mod, I would like to see it. I still wouldn't buy this since there is so much older gear that can be refurbished.
Thanks Tony for posting this. Mike at mikesradiorepair sent me the link to this video. That got me thinking about the one I just introduced in a video. This is some nasty stuff and appreciate you pointing this out. Great video my friend. Subscribed.
Tony, I'd really enjoy seeing the design, fabrication and installation of a linear power supply in that unit if you have the desire and time to create the video.
Don't forget that linear power supplies also generate earth leakage: even the short mains cable alone will generate 20uA leakage (due to the wires forming parallel plate capacitors). Earthing the BNC shells is the best way to improve the safety of both delicate electronics and humans. (PS I have a deep distrust of switch mode power supplies and prefer linear ones but then I am getting very old).
Is there anyway you could do a review of the new version? The one with the color TFT screen and they have fixed the grounding issue. But apparently there is still some leakage trouble with 50 V coming to to the front Connectors. I’m getting ready to order one of these, and your input is always one of the most helpful and respected! Thanks for your content!
The new version also has the same switch mode power supply, and same problem. see video ruclips.net/video/pQxHFGXHPXg/видео.html That Engineer provides information for a power supply replacement, that is reasonable cost.
@@johnhodgson4216 you linked to the FY 6600 which was a concurrent model to the 3200. The updated versions are the 6800 and now the 6900. Those two models use a grounded plug and different smps and leakage issue is resolved
The device is also sold with a US 2 pin connector in the U.K. (Doh!) where ONLY 3 pole socket wall outlets are allowed (i.e. 3rd pin earthed / grounded). I quite agree about the damage to any equipment connected to it and the stated 100 micro amps present no danger of shock. In the U.K. it is common for an earth leakage of 30 to 40 micro-amps to occur in a 3 core 5 metre mains cable with nothing connected to it (i.e. just the cable plugged into the wall socket!) The threshold of feeling at 50/60Hz is about 1mA with a lethal current at some 30mA: the tingling feeling is most likely due to the high frequency of the SM PSU . Thanks for the warning: my FY3200S is about to be modified with an IEC connector, 3 core mains cable, and a 1 Amp plug fuse (yep the plugs are individuallly fused over here). Nice review.
@@SpeccyMan Great: the IEC connector fits in without any real difficulty. You could also increase the cross section area of the earthing cable where they connect with the metallic parts of the connectors: this would give the mains fuse time to blow before any large fault currents could occur.
Plug in the USB to a grounded host computer and the leakage goes away. What cracks me up the most are all the comments from seasoned electronics vets....and here I am just starting out a couple months back....lol!! The problem is that the old guys don't believe in computers so the simplest answer eludes them every time!!!
John, you're right... partially. Seasoned vets also know that once you have hard ground as a reference, you limit the usage as it is impossible to use the generator 'floating' and use some level in the circuit as a reference ground. You will short your circuit to ground. A typical caveat of beginners is not knowing the difference between floating or grounded use when using for instance a scope. They learn after blowing up their first scope. So listen carefully to old guys as they can save you a lot of money.
Well the leakage doesn't go away, your just shorting the leakage current to ground...and that leakage current is also going to affect the DC that the USB connection is running to your laptop. 100ma at 115vac with 0.707 power factor is 8.13 watts of power your grounding into your laptop.
@@SpeccyMan The leakage current in both of my function generators were so bad, that they are unusable until I replace the PSU itself with a proper power supply.
The weird waveform that that supposed to be AM (but not) will produce something on a radio if you key in 1/10 of the intended frequency. It's make you wonder if the designers ever saw an AM radio before. I have a Stancor P-8364 transformer that I might just use to upgrade the power supply on this thing. Disappointing.
I have fixed this by putting insulation trasformer in between orignal switching power supply and mains. Just used small 20VA toroidal transformer and wound another 230v winding on it making it a 230/230v insulation transformer. Installed it directly into the generator. Cost me 10€ works great
At 3:14, you inserted the probe into the HOT side. Better would be the common or ground pin.
Please answer this if you don't mind
Yes there is a fair amount of leakage resulting in almost mains voltage on the exposed BNC connectors, but we need to remember this is in the microvolt range, so if you grab the connector, you will not get a jolt of it, there isn't enough current, BUT, it can and will, as stated in the video, destroy sensitive devices such as JFET's and static sensitive devices, processors and things like that.....Thanks for getting the word out there and letting people know about this....
Microvolt range or micro Amps? It's the volts that jolts but the millis that killis (micros really are quite friendly)!
Switch mode power supply has issues because of poor grounding. So beware of this when testing other devices
with it. Probably need it plugged into an isolation transformer. Good idea to replace it with a linear style PS.
Did a similar thing to genius3258, installed 2 back to back 240V/9V little transformers between power supply and mains. Also added a switch to select floating / grounded. BTW if you have a basic model (low bandwidth) you can increase this by holding the menu button a specific amount of time while powering on. I added a 8-pin microcontroller that simulates a key press during power-up. By tweaking the delay loop I now have 15Mhz instead of 2 :-)
Those are some great tips. Thanks for sharing!
What would be a good budget signal generator that does am and FM modulation?
What additional guidance do you give when using an isolation transformer with one or more of these units?
Scary. If you're going to do the power supply mod, I would like to see it. I still wouldn't buy this since there is so much older gear that can be refurbished.
The reading is correct. You are measuring between hot in the plug strip, and ground on the generator which is at earth.
Thanks Tony for posting this. Mike at mikesradiorepair sent me the link to this video. That got me thinking about the one I just introduced in a video. This is some nasty stuff and appreciate you pointing this out. Great video my friend. Subscribed.
Tony, I'd really enjoy seeing the design, fabrication and installation of a linear power supply in that unit if you have the desire and time to create the video.
Don't forget that linear power supplies also generate earth leakage: even the short mains cable alone will generate 20uA leakage (due to the wires forming parallel plate capacitors). Earthing the BNC shells is the best way to improve the safety of both delicate electronics and humans. (PS I have a deep distrust of switch mode power supplies and prefer linear ones but then I am getting very old).
Hey Tony, is this thing UL rated?
This device should have earthed mains connector. As it doesn't, you should connect the BNC ground to your ground to avoid problems.
Is there anyway you could do a review of the new version? The one with the color TFT screen and they have fixed the grounding issue. But apparently there is still some leakage trouble with 50 V coming to to the front Connectors. I’m getting ready to order one of these, and your input is always one of the most helpful and respected! Thanks for your content!
The new version also has the same switch mode power supply, and same problem. see video ruclips.net/video/pQxHFGXHPXg/видео.html That Engineer provides information for a power supply replacement, that is reasonable cost.
@@johnhodgson4216 you linked to the FY 6600 which was a concurrent model to the 3200. The updated versions are the 6800 and now the 6900. Those two models use a grounded plug and different smps and leakage issue is resolved
Does anyone have a schematic for these?
The device is also sold with a US 2 pin connector in the U.K. (Doh!) where ONLY 3 pole socket wall outlets are allowed (i.e. 3rd pin earthed / grounded). I quite agree about the damage to any equipment connected to it and the stated 100 micro amps present no danger of shock. In the U.K. it is common for an earth leakage of 30 to 40 micro-amps to occur in a 3 core 5 metre mains cable with nothing connected to it (i.e. just the cable plugged into the wall socket!) The threshold of feeling at 50/60Hz is about 1mA with a lethal current at some 30mA: the tingling feeling is most likely due to the high frequency of the SM PSU . Thanks for the warning: my FY3200S is about to be modified with an IEC connector, 3 core mains cable, and a 1 Amp plug fuse (yep the plugs are individuallly fused over here). Nice review.
Mine came with a UK plug. However the Earth is not connected so the leakage is there. Will be doing the IEC connector mod.
@@SpeccyMan Great: the IEC connector fits in without any real difficulty. You could also increase the cross section area of the earthing cable where they connect with the metallic parts of the connectors: this would give the mains fuse time to blow before any large fault currents could occur.
2 pole IEC’s are allowed in the U.K. with some restrictions about isolation. Plenty of U.K./CE approved products with them.
Seems like you're better off with refurbishing a Tek or HP or Fluke sig gen. The lower priced (
Plug in the USB to a grounded host computer and the leakage goes away. What cracks me up the most are all the comments from seasoned electronics vets....and here I am just starting out a couple months back....lol!! The problem is that the old guys don't believe in computers so the simplest answer eludes them every time!!!
John, you're right... partially. Seasoned vets also know that once you have hard ground as a reference, you limit the usage as it is impossible to use the generator 'floating' and use some level in the circuit as a reference ground. You will short your circuit to ground. A typical caveat of beginners is not knowing the difference between floating or grounded use when using for instance a scope. They learn after blowing up their first scope. So listen carefully to old guys as they can save you a lot of money.
Well the leakage doesn't go away, your just shorting the leakage current to ground...and that leakage current is also going to affect the DC that the USB connection is running to your laptop. 100ma at 115vac with 0.707 power factor is 8.13 watts of power your grounding into your laptop.
@@johnhodgson4216 The leakage current is in the microamps not milliamps range! 100uA isn't 100mA.
@@SpeccyMan The leakage current in both of my function generators were so bad, that they are unusable until I replace the PSU itself with a proper power supply.
The weird waveform that that supposed to be AM (but not) will produce something on a radio if you key in 1/10 of the intended frequency. It's make you wonder if the designers ever saw an AM radio before. I have a Stancor P-8364 transformer that I might just use to upgrade the power supply on this thing. Disappointing.