Siglent SDS2000X Plus

[ozkarah]

The original MOSFETs are FQPF9N50C. However, it was not possible to find a seller here.

A quick search for FQPF9N50C returned results that indicate the item is obsolete but a few retailers in Turkey, some of them reporting number of items in stock, claim to have the item. Just out of curiosity since I didn't do business with any of them: Did you contact them to find out that they actually didn't have any stock?

Few examples from what I could find:

https://karakoyelektronik.com/transistor/fqpf9n50c-23318
https://www.ulutaselektronik.com/urun/fqpf9n50c-to-220f-9a-500v-44w-0-8-n-channel-mosfet
https://fevaris.com/mosfet/fqpf9n50c-n-kanal-9a-500v-to-220f-mosfet-transistor

I have seen those sellers, but never contacted them. They are not official importers and it is not easy to be sure that the parts are genuine. 
I didn't want to risk the process. The substitute part is better in specs and is sold by the official importer (ozdisan.com).

[ozkarah]

Good news. The scope is back again.

First MOSFETs were replaced (FQPF9N50C -> P15F60HP2F-5600). However, there was still no output voltage.

Then, replacing the IC (IC6599) did the trick. So far, everything looks okay...

[tautech]

Good news. The scope is back again.

First MOSFETs were replaced (FQPF9N50C -> P15F60HP2F-5600). However, there was still no output voltage.

Then, replacing the IC (IC6599) did the trick. So far, everything looks okay...

Good work.

Did you check the PSU outputs were to Service manual spec ?

[2N3055]

Nice work!!

[ozkarah]

Good news. The scope is back again.

First MOSFETs were replaced (FQPF9N50C -> P15F60HP2F-5600). However, there was still no output voltage.

Then, replacing the IC (IC6599) did the trick. So far, everything looks okay...

Good work.

Did you check the PSU outputs were to Service manual spec ?

Yes, all are in the spec

[Martin72]

Then, replacing the IC (IC6599) did the trick. So far, everything looks okay...

It would be interesting to know how the chip is supplied.
ICs like this don't just die, their Achilles' heel is the maximum supply voltage.
The driver outputs are usually protected, so a defect in the switching FETs has no effect.
Maybe a spike in the input voltage killed the part.

[ozkarah]

It would be interesting to know how the chip is supplied.
ICs like this don't just die, their Achilles' heel is the maximum supply voltage.
The driver outputs are usually protected, so a defect in the switching FETs has no effect.
Maybe a spike in the input voltage killed the part.

You are right Martin. It is hard to guess which component failed first and why.
It might be the mains voltage but never happened to any device at the same location before.

[Martin72]

It is hard to guess which component failed first and why.

Why, was more defective than the control IC?

[tautech]

It is hard to guess which component failed first and why.

Why, was more defective than the control IC?

Yep, also 1 MOSFET, see:
https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg5829655/#msg5829655

[ozkarah]

It is hard to guess which component failed first and why.

Why, was more defective than the control IC?

No, there was no physical sign of failure on the components.
However, I honestly don't know how to guess if the IC if broken because of shorted MOSFET of MOSFET is broken because IC started to send unexpected signals to the gate of the MOSFET.

Fortunately, compatible components were obtainable and cheap.


Let's hope this is the end of this story...

[BH3XON]

Good news. The scope is back again.

First MOSFETs were replaced (FQPF9N50C -> P15F60HP2F-5600). However, there was still no output voltage.

Then, replacing the IC (IC6599) did the trick. So far, everything looks okay...

Good work.

Did you check the PSU outputs were to Service manual spec ?

The 6599 is a half-bridge resonant controller. However, due to its outdated design, the startup process lacks optimized switching timing for the upper and lower MOSFETs. This results in hard switching during the first two or three cycles and reverse recovery issues of the MOSFET body diodes, causing brief shoot-through between the upper and lower switches – a common failure mechanism in this topology.

It is possible that Siglent engineers overlooked this issue and selected MOSFETs with a reverse recovery time (trr) of 335 ns, which may lead to higher failure rates. To mitigate this:

​Replace with faster MOSFETs: Use MOSFETs with trr ​**<200 ns**​ to minimize reverse recovery-induced current spikes.
​Maintain Coss consistency: Ensure the output capacitance (Coss) of the new MOSFETs closely matches the original devices. Excessive Coss could compromise the Zero Voltage Switching (ZVS) advantage inherent to this topology.

[ozkarah]

The 6599 is a half-bridge resonant controller. However, due to its outdated design, the startup process lacks optimized switching timing for the upper and lower MOSFETs. This results in hard switching during the first two or three cycles and reverse recovery issues of the MOSFET body diodes, causing brief shoot-through between the upper and lower switches – a common failure mechanism in this topology.

It is possible that Siglent engineers overlooked this issue and selected MOSFETs with a reverse recovery time (trr) of 335 ns, which may lead to higher failure rates. To mitigate this:

​Replace with faster MOSFETs: Use MOSFETs with trr ​**<200 ns**​ to minimize reverse recovery-induced current spikes.
​Maintain Coss consistency: Ensure the output capacitance (Coss) of the new MOSFETs closely matches the original devices. Excessive Coss could compromise the Zero Voltage Switching (ZVS) advantage inherent to this topology.

The datasheet of the new MOSFETS (P15F60HP2F-5600) suggests the reverse recovery time is 88 ns. I think this should eliminate future problems, right?

[BH3XON]

If the damage was caused by this issue, I think there should be an improvement.

[jujava]

Dear all,

I am new on the forum. I have a SDS2354X plus with whom I am having communication problems
I cannot get to control it via SCPI commands from a USB connection made at the back of the scope using usbtmc protocol.
It is working without problem with VX11 using the RJ45 network port. The siglent vendor told me they "contacted the engineers" but it has been months.

My take on this is that the usb port at the back of the scope is just a standard port like those in front, good to connect a usb stick or disk, but it is not a bidirectional communication port.
Usually sending the command *IDN? on any hardware even dating back to the 1980 gives back the name of the device, which does not seem to work here.

What do you think about that? Someone had any experience trying to control such a scope via usb ?

best regards and thank you for your help !

[tautech]

Dear all,

I am new on the forum. I have a SDS2354X plus with whom I am having communication problems
I cannot get to control it via SCPI commands from a USB connection made at the back of the scope using usbtmc protocol.
It is working without problem with VX11 using the RJ45 network port. The siglent vendor told me they "contacted the engineers" but it has been months.

My take on this is that the usb port at the back of the scope is just a standard port like those in front, good to connect a usb stick or disk, but it is not a bidirectional communication port.
Usually sending the command *IDN? on any hardware even dating back to the 1980 gives back the name of the device, which does not seem to work here.

What do you think about that? Someone had any experience trying to control such a scope via usb ?

best regards and thank you for your help !

Welcome to the forum.

Which program are you using to try to control the scope ?
Often you will require USB connectivity drivers like those found in the NIVISA Runtime package.

An IVI driver is available here:
https://int.siglent.com/download/drivers/?ProId=53

[jujava]

Thank you Tautech for the feedback.

I am using octave instrument-control on linux. It is essentially a low level toolbox in which you send message to the communication port (serial,usb,eth).
For what is worth, In 15 years I never had a single instrument that would not work with this method and I never have to use a driver.
Even fake USB protocols such as RS232-over-usb are working like a charm.

The basic code looks like that
%%%%%%
pkg load instrument-control
t0 = usbtmc('/dev/usbtmc0') # Open interface to USB instrument
usbtmc_write(t0, '*IDN?')  # write to listener,
data = usbtmc_read(t0, 10000) # Blocking read call, returns uint8 array
char(data);  Convert uint8 array to string: should tell me "SIGLENT 2345X serial number etc"
usbtmc_close(t0) ;  # close usbtmc session
%%%%%%

Notice that instrument-control over eth0 using VX11 protocol works perfectly.

Following my vendor advices, I did try to run the scope on a windows 11 laptop using the driver proposed by the vendor (IVI driver).
I get a strange message telling me usbtmc not working.  It seems the usbtmc protocol cannot be started.
The message I get clicking on "Device not Started (usbtmc) is the following:

Device USB\VID_F4EC&PID_1011\SDS2PEEC7R1068 had a problem starting.
Driver Name: oem98.inf
Class Guid: {a9fdbb24-128a-11d5-9961-00108335e361}
Service: Usbtmc
Lower Filters:
Upper Filters:
Problem: 0x0
Problem Status: 0xC00000E5
[4:27 PM]
problem starting.

The scope use operating system V5.4.0 obtained here: https://www.siglenteu.com/download/17542/?tmstv=1740767711
The scope use firmware 1.6.2R5 obtained here: https://www.siglenteu.com/download/17353/?tmstv=1740767711

Do you have any idea what is going on ? Could it be that the scope is faulty, or is it simply that the usb port is just a dumb usb port only made for usb hard disk/ stick ?
Did anybody try to get data from the scope using usb protocol and could inform me if it is at any rate possible ?
A careful reading of the manual and spec is actually never saying we can communicate with usbtmc, only network ...

best regards and thank you if you can help me debug that problem

[tautech]

Thank you Tautech for the feedback.

I am using octave instrument-control on linux. It is essentially a low level toolbox in which you send message to the communication port (serial,usb,eth).
For what is worth, In 15 years I never had a single instrument that would not work with this method and I never have to use a driver.
Even fake USB protocols such as RS232-over-usb are working like a charm.
..................
Following my vendor advices, I did try to run the scope on a windows 11 laptop using the driver proposed by the vendor (IVI driver).
I get a strange message telling me usbtmc not working.  It seems the usbtmc protocol cannot be started.
The message I get clicking on "Device not Started (usbtmc) is the following:

Device USB\VID_F4EC&PID_1011\SDS2PEEC7R1068 had a problem starting.
Driver Name: oem98.inf
Class Guid: {a9fdbb24-128a-11d5-9961-00108335e361}
Service: Usbtmc
Lower Filters:
Upper Filters:
Problem: 0x0
Problem Status: 0xC00000E5
[4:27 PM]
problem starting.
............
Do you have any idea what is going on ? Could it be that the scope is faulty, or is it simply that the usb port is just a dumb usb port only made for usb hard disk/ stick ?
Did anybody try to get data from the scope using usb protocol and could inform me if it is at any rate possible ?
A careful reading of the manual and spec is actually never saying we can communicate with usbtmc, only network

See the programming manual P18:
Establishing Communications
Install NI-VISA
USB control requires the National Instruments NI-VISA Library for communications.
https://int.siglent.com/u_file/download/24_03_05/SDS2000X%20Plus_ProgrammingGuide_EN11F.pdf

It seems your USB communication SW is not supported. 

More study:
https://siglentna.com/operating-tip/usb-connectivity-checklist/
https://siglentna.com/application-note/lxi-tools/

[KungFuJosh]

Do you have any idea what is going on ? Could it be that the scope is faulty, or is it simply that the usb port is just a dumb usb port only made for usb hard disk/ stick ?
Did anybody try to get data from the scope using usb protocol and could inform me if it is at any rate possible ?
A careful reading of the manual and spec is actually never saying we can communicate with usbtmc, only network ...

best regards and thank you if you can help me debug that problem

It won't work that way without getting the drivers to work first. Once the drivers are installed, the device connection has to also work with the drivers you chose before what you're trying to do will work.

I don't have that scope anymore, but when I did, I used the NI-VISA drivers for it.

[jujava]

helo Tautech & KungFuJosh

Thank you for the info, I will have a look.
I agree that it seems you have to go through the driver to talk to the machine, that is definitely a first for me !
Most probably, I will stick with LXI and RJ45 as installing all these drivers on linux may not even be possible ...
For the case of a portable single instrument connection, a usb-to-RJ45 adaptor could even be a simpler option.
best regards and thank you very much for your kind help.

[Sorama]

I don't have that scope anymore…

@kungfujosh
May I ask with what scope you replaced it with ?

[tautech]

I don't have that scope anymore…

@kungfujosh
May I ask with what scope you replaced it with ?

Pretty sure Josh went to the newer design 12bit SDS2000X HD.
A little more compact and with additional memory management features.
Almost silent, a super quiet DSO.

[KungFuJosh]

I don't have that scope anymore…

@kungfujosh
May I ask with what scope you replaced it with ?

Rob is correct, I have the HD version now. Photo attached. 😉

[Sorama]

I don't have that scope anymore…

@kungfujosh
May I ask with what scope you replaced it with ?

How could forget. 
HD surely stands for High Density grip 
Rob is correct, I have the HD version now. Photo attached. 😉

[KungFuJosh]

HD surely stands for High Density grip 

100%!!

[jujava]

Dear all,

I would like to ask a stupid question regarding the signal generator on the SDS2000X Plus

It seems that I can only control the frequency first digits rotating the knob.
Say, if I am around 10 kHz, rotating fast I get 12,13kHz while rotating slow I can get 10.1kHz, 10,2kHz, etc.

Obviously, in many situations one wants a finer tuning. This is usually achieved by selecting the digit you want to modify, say the third 10.00X, leading to 10.001, 10.002, etc.

Did I completely miss in the manual how we can do that or is it just not possible ?

best regards and thank you !