EDIT: Actually, I found the "Component Level Service Manual"on an exotic website
but not really useful: Tek was already using hybrid modules for the analog front-end, thanks anyway
I could only find the "Module Level Service Manual" there, I had to search for TDS520 "component level" service manual in order to find it somewhere else.
The Tek 2232 was probably one of the latest
As hobbyists, we have no access to either Hybrids or analog ASICs, so both the "old" Tek 2232 and these cheap low-end DSOs are interesting to look at.
Well, that's confusing: for a single ADC, you need to meet was is known as the "Nyquist criterion", see Wikipedia ...
But what I am saying is only good when you have a single ADC...
As there are up to 10 of them, they can be clocked so that each one is sampling with a calibrated period that is 1/10 of the sampling period, thus achieving an effective sampling frequency of 1 GHz. Then, by digital reconstruction, you are able to get a 1 GSPS resolution digital signal, that you can THEN filter digitally to whatever you want below that.
And in this case, I really don't know if what I said for a single ADC is still valid, or if aliasing "magically" cancels itself by using several of them working with such a clock scheme, only requiring a max signal frequency of 1 GHz/2=500 MHz...
I think, Hnatek need immediately solve this design bug. If there need boot time cal connection it need solve different way.
500 ohm directly from CH1 to CH2 center whole boot up time!
Maybe 2/3 of the boot time is the OS coming up. After that, the DSO app is run.
I have not observed any scope related state changes, prior to DSO running. This
leads me to believe that the problem is caused by the initial state of the shift register,
controlling the relay. Hantek should have added a tristate control, and pullup/down resistors
to all of the outputs, so the controls could be set to a knows state, prior to software initialization.
Looking at tinhead's (very handy) schematic, it appears that we may be able to force the
shift register to clear, by adding a RCD circuit to the SRCLR pin.
Just curious if anyone else is experiencing this behavior? If I power-on my
Hantek, with a USB stick installed (front port), the stick is not recognized by the
DSO application. The OS, however, does see the stick, and auto-mounts it.
I need to unplug the stick, and re-insert, before the scope will flag it's presence.
500 ohm directly from CH1 to CH2 center whole boot up time!
are you sure ? When off, the self-calibration relay is not connected, the attenuator not active, so in principle 1.2M input
(the state of relays on my schematic is off mode)
Yes, all what I can now look is HW5 and HW7 with FW, ..225, 420, 427patch, 531.1... all have this problem and afaik problem was also before. Not nice but can live with it. If need lot of USB things all times, it is good to buy short cable.... no need wear scope USB connector. (specially becouse these quality is just as entertainment quality (all USB connectors not only hantek but who care... today electronic need only 1-3year lifetime and tomorrow we go more short "designed" lifetimes.)..
yep, i know it. The funny part is, firmware update menu is even trying to access to stick, but
it fails because stick didn't exists (but the stick led is blinking ...) So it seems the firmware
just don't see a specific flag. Not sure if this is really firmware bug or linux hotplug delay bug,
it takes anyway a bit long to recognize usb devices. Maybe a delay before dso.exe will be loaded can help out.
Well, channel 2 has stopped working and also the vertical position control (it jumps back down to 0). The oscilloscopes self calibration stops at step 13.
Channel 1 seems fine.
Anyone know whats the cause or how to fix.
I bought it from www.youroscilloscope.com. I think they dropship from Hantek china.?
I'm in europe/cyprus.
So do you think i have to ship the oscilloscope back or is there an easier solution, maybe in europe?
I'll play around with it, and see if I can figure out
what they're doing.
This is also not good to measure real BW becouse input reactance. 50 ohm termination is not good method becouse it is not matced to 1M 20+-3pF input. It do not see scope input as pure resistive load. SWR is not 1.
Now Hantek input is 20 +-3pF