Trying to power the device from the battery doesn't work for me. Doing so, it succeeded a few times only, but normally the screen simply stays blank. This is what I've observed:

* The Li-Ion battery is in good condition, V_OC = 4 V
* With USB connected, the battery is being charged with I = ~15 mA
* With USB disconnected, a tiny current is drawn from the battery, I = 5 ... 50 µA. However, actuating the on/off switch won't power-up the device.
* Connecting a 4700 µ cap in parallel to the battery didn't help.
* I removed the battery and connected the terminals in the battery compartment to a linear power supply as a low-impedance 4 V source. Same situation as above: Actuating the on/off switch won't power-up the device.

Would be great if anybody could give me a hint what's going wrong here.

Try measuring the voltage at the battery connector (marked B+ and B-)
which bypasses the DW01 protection IC.

Ah yes this is a known issue that has confused others too. I suggest posting the solution to the forum so that others with the same problem can know about it.

On 02/12/2020 23:22, DL3TG wrote:

>
> I could further track it down to a single remaining issue: After
> re-inserting the battery, obviously one has to "kick-start" the device by
> plugging/unplugging to USB once. After this, it will run from battery
> power w/o further issues.
>
> The rest of the power-up problems I wrote about was caused by the
> relatively high 10 Ohm shunt resistor inside my ammeter I was using for
> debugging (shame on me ...). That's why I removed my message from the
> board.
>
> Best regards,
> Thomas

​My V2plus4 never turns on after removing and reattaching the battery. ​However, when I charge it with a USB cable for a short time, the LED lights up, and after that, it turns on again only with the battery.
--
TENKO

Am 02.12.2020 16:35 schrieb Tenko46T <nasa46vb@gmail.com>:

> ​My V2plus4 never turns on after removing and reattaching the battery.
​However, when I charge it with a USB cable for a short time, the LED lights
up, and after that, it turns on again only with the battery.
> \--
> TENKO

I also had to kickstart it

No problem... If you know it

A note.. A sticker

A post it note or similar that says in FIRST use and after change of lipo you
have to do that...

Would save others to have that same problem

Dg9bfc sigi

_._,_._,_

* * *

That's a good suggestion.
The more analog knowledge and experience we have, the more likely we try various cure.
I regretted that I removed the battery when it didn't turn on for the first time,
and I checked the voltage because I was worried that I might have installed the battery with reverse polarity.
I think it would be helpful if a small piece of paper with hint were included.
On the other hand, I understand that such careful support for low price OSHW products is difficult, too.
--
TENKO

i an quite sure that a sticker would help

the v2pus4 costs nearly double as the saa2n ... i am sure there are a
few pennies left for a small printed user manual (quick start guide) or
a small sticker that says "after install of fresh battery you have to
"kickstart" the unit with connecting it to a charger or pc"

a piece of paper with a note ... thrown inside the box before sending
out ... thats all needed

so Tenko ... now that you know it ... and hopefully after kickstarting
it ... how is your new unit?!? ;-)

(i know its good cause i also have one .. grin)

greetz Sigi DG9BFC

Am 03.12.2020 um 14:41 schrieb Tenko46T:

> That's a good suggestion.
> The more analog knowledge and experience we have, the more likely we
> try various cure.
> I regretted that I removed the battery when it didn't turn on for the
> first time,
> and I checked the voltage because I was worried that I might have
> installed the battery with reverse polarity.
> I think it would be helpful if a small piece of paper with hint were
> included.
> On the other hand, I understand that such careful support for low
> price OSHW products is difficult, too.
> --
> TENKO
>

They've added it to the product descriptions now but I'll also be fixing
up the user guide (it's missing a getting started section which tells
you this kind of stuff and also descriptions of the buttons and LEDs).

Hello, Sigi.

Your proposal went through. Gabu-chan is really an angel.

Of course, it works well now. The V2 Plus4 is my favorite because of its beautiful titanium silver finish and the durability of USB Type B.
(But for some reason the Nano-VNA App doesn't take screen capture ...)

In any case, I want to back up the main flash, so I will disassemble it again and look for SWD pins.
We have to be careful about static electricity because the air is dry in this season.
--
TENKO

Screen capture does work also on the plus4..

Single scan does not work..

Continous scan works if you manually type in 00 20 30 00 in comms window

3000 points max

First connect.. Test screen capture

Should work

Click on continous scan.. It will scan and just before first scan is finished
it will halt... And show usb mode in lcd screen

Now type in above command and it will continue scanning

Greetz sigi dg9bfc





Am 04.12.2020 05:13 schrieb Tenko46T <nasa46vb@gmail.com>:

> Hello, Sigi.

>

>
> Your proposal went through. Gabu-chan is really an angel.
>
>

>

> Of course, it works well now. The V2 Plus4 is my favorite because of its
beautiful titanium silver finish and the durability of USB Type B.

>

> (But for some reason the Nano-VNA App doesn't take screen capture ...)

>

>
> In any case, I want to back up the main flash, so I will disassemble it
again and look for SWD pins.
> We have to be careful about static electricity because the air is dry in
this season.

>

> \--
> TENKO



_._,_._,_

* * *

Hello, Sigi.

Thank you for the information.
Attached is my clean capture. Like this, the scan becomes a corrupted image.
Do you have any idea?
--
TENKO

What fw do you use??



Am 04.12.2020 13:42 schrieb Tenko46T <nasa46vb@gmail.com>:

> Hello, Sigi.
>
>

>

> Thank you for the information.

>

> Attached is my clean capture. Like this, the scan becomes a corrupted image.
> Do you have any idea?

>

> \--
> TENKO
> 



_._,_._,_

* * *

and this is my sceen capture

yes i have an idea ... you sure have older fw on your plus4 ;-)

greetz sigi dg9bfc

Am 04.12.2020 um 12:42 schrieb Tenko46T:

> Hello, Sigi.
>
> Thank you for the information.
> Attached is my clean capture. Like this, the scan becomes a corrupted
> image.
> Do you have any idea?
> --
> TENKO
>

Hello Sigi,

The symptoms are the same for both fw.
nanovna-v2 -20201122 v2plus4.bin
nanovna-v2 -20201124 v2plus4.bin

The image captured when it is cold is jagged, but it will be fixed normally when heated.
It is not known whether the cause is LCD unit or main board.

Also, the continuous sweep command you told me works well. Thank you.
--
TENKO

P.S. About jagged screen-captured images

I experimented with the V2plus4  LCD changing from 4 ” to 2.8 ” and confirmed that screen capture works well even at low temperatures.
The firmware was built by editing the make command. The attached file is an experimental photo.

It is said that the screen capture function is realized by reading the frame memory from the LCD module,
and when I observed the SPI clock during screen capture, it seemed to run at the specification limit of the ST7796.
So I think this problem is probably a variation in the quality of the 4 inch LCD module.

But there is no problem so far, so I will use it as it is.
The temperature in the Northern Hemisphere will drop further in the coming winter, so other than my V2plus4 screen captures may have problems.
--
TENKO

Could be a signal integrity problem on the SPI bus too. They worsen at low
temperatures. You can try inserting a 33-100ohm resistor in series on the
CLK, MISO and MOSI lines.

El dom., 6 dic. 2020 7:41, Tenko46T <nasa46vb@gmail.com> escribió:

> P.S. About jagged screen-captured images
>
> I experimented with the V2plus4 LCD changing from 4 ” to 2.8 ” and
> confirmed that screen capture works well even at low temperatures.
> The firmware was built by editing the make command. The attached file is
> an experimental photo.
>
> It is said that the screen capture function is realized by reading the
> frame memory from the LCD module,
> and when I observed the SPI clock during screen capture, it seemed to run
> at the specification limit of the ST7796.
> So I think this problem is probably a variation in the quality of the 4
> inch LCD module.
>
> But there is no problem so far, so I will use it as it is.
> The temperature in the Northern Hemisphere will drop further in the coming
> winter, so other than my V2plus4 screen captures may have problems.
> --
> TENKO
>
>

MISO, MOSI and SCK already have damping resistors.
Certainly the SPI waveform is ringing. However, with my oscilloscope, the GNDs of all channels are not isolated, so I could not evaluate them accurately.
Near the LCD module, a dedicated buck converter generates and supplies 3.3 V. On the other hand, since the MPU voltage is 3.0 V, the noise margin decreases from the beginning. This can cause signal integrity problems.

On Sun, Dec 6, 2020 at 09:27 PM, Carlos Cabezas wrote:

>
> Could be a signal integrity problem on the SPI bus too. They worsen at low
> temperatures. You can try inserting a 33-100ohm resistor in series on the
> CLK, MISO and MOSI lines.
>
> El dom., 6 dic. 2020 7:41, Tenko46T < nasa46vb@gmail.com > escribió:
>
>> P.S. About jagged screen-captured images
>>
>> I experimented with the V2plus4  LCD changing from 4 ” to 2.8 ” and
>> confirmed that screen capture works well even at low temperatures.
>> The firmware was built by editing the make command. The attached file is
>> an experimental photo.
>>
>>
>> It is said that the screen capture function is realized by reading the
>> frame memory from the LCD module,
>> and when I observed the SPI clock during screen capture, it seemed to run
>> at the specification limit of the ST7796.
>> So I think this problem is probably a variation in the quality of the 4
>> inch LCD module.
>>
>> But there is no problem so far, so I will use it as it is.
>> The temperature in the Northern Hemisphere will drop further in the coming
>> winter, so other than my V2plus4 screen captures may have problems.
>> --
>> TENKO
>
>

--
TENKO

try this on your plus4

dg9bfc sigi

Am 04.12.2020 um 04:13 schrieb Tenko46T:

> Hello, Sigi.
>
> Your proposal went through. Gabu-chan is really an angel.
>
> Of course, it works well now. The V2 Plus4 is my favorite because of
> its beautiful titanium silver finish and the durability of USB Type B.
> (But for some reason the Nano-VNA App doesn't take screen capture ...)
>
> In any case, I want to back up the main flash, so I will disassemble
> it again and look for SWD pins.
> We have to be careful about static electricity because the air is dry
> in this season.
> --
> TENKO
>

I have Plus4 and some problems vs LCD screencapture.

Slowdown SPI read speed - not help (i made more then 32 divider for SPI)

Replace LCD module from my V2Plus, i get stable read work on current SPI speed.

Also this LCD module have problem, it flick in some time, for disable flick i need reduce fremerate setting in last firmware.

Possible problem in LCD power, it use Plus4 board power?

The LCD screen capture works well with ILI9341 chip , but not good with ST7796 chip.

However, it can be fixed by warming the V2Plus4, so I think it is related to the Vth variation of the CMOS process.

The 3.3V LCD power is supplied by a dedicated buck converter inside the V2Plus4.

Thank you for 511 point firmware. I could sweep Nano-VNA App correctly and I could do L/C match.

--
TENKO

using your latest plus4 fw (with 511pt) works fine here ... also
screenshots works fine

???greetz sigi dg9bfc

Am 03.01.2021 um 13:36 schrieb DiSlord:

> I have Plus4 and some problems vs LCD screencapture.
>
> Slowdown SPI read speed - not help (i made more then 32 divider for SPI)
>
> Replace LCD module from my V2Plus, i get stable read work on current
> SPI speed.
>
> Also this LCD module have problem, it flick in some time, for disable
> flick i need reduce fremerate setting in last firmware.
>
> Possible problem in LCD power, it use Plus4 board power?
>

On Sun, Jan 3, 2021 at 12:39 PM, Siegfried Jackstien wrote:

>
>
>
> using your latest plus4 fw (with 511pt) works fine here ... also
> screenshots works fine
>
>
>
> ???greetz sigi dg9bfc
>
> Am 03.01.2021 um 13:36 schrieb DiSlord:
>

As i write:

>
>
> Replace LCD module from my V2Plus, *i get stable read work* on current SPI
> speed.
>

Some LCD modules have correct work, and no flicker defect, but some have it, this can related to 3.3v power supply, but i not test it

Hmm.. In my saa2n plus.. And in plus4 i added a cap to 3v3 rail..

Maybe it is cause some lcd draw more current as other?!? Just guessing

Dg9bfc sigi



Am 03.01.2021 22:47 schrieb DiSlord <dislordlive@gmail.com>:

> On Sun, Jan 3, 2021 at 12:39 PM, Siegfried Jackstien wrote:
>

>

>> using your latest plus4 fw (with 511pt) works fine here ... also
screenshots works fine

>>

>> ???greetz sigi dg9bfc

>>

>> Am 03.01.2021 um 13:36 schrieb DiSlord:

>

> As i write:
>

>

>>
> Replace LCD module from my V2Plus, **i get stable read work** on current SPI
speed.

>

> Some LCD modules have correct work, and no flicker defect, but some have it,
this can related to 3.3v power supply, but i not test it



_._,_._,_

* * *

Hi Sigi,

I downloaded the Dislord firmware from the direct download link you provided back on 03-Jan-2021 and loaded it into my SAA-2N. Very nice having this available. However, when I click the link, it just downloaded that specific firmware version. Can you provide a link to a URL where Dislord's latest firmware versions are available?

Thanks, Ken - WB0OCV

Sent from Mail for Windows 10

From: Siegfried Jackstien
Sent: Sunday, January 3, 2021 05:44 AM
To: NanoVNAV2@groups.io
Subject: Re: [nanovnav2] NanoVNA V2Plus4: No power-up with battery supply

try this on your plus4
dg9bfc sigi
Am 04.12.2020 um 04:13 schrieb Tenko46T:
Hello, Sigi.

Your proposal went through. Gabu-chan is really an angel.
Of course, it works well now. The V2 Plus4 is my favorite because of its beautiful titanium silver finish and the durability of USB Type B.
(But for some reason the Nano-VNA App doesn't take screen capture ...)

In any case, I want to back up the main flash, so I will disassemble it again and look for SWD pins.
We have to be careful about static electricity because the air is dry in this season.
--
TENKO

Hi, when you put the battery inside the NanoVna V2plus4 for the first time
you have to plug the USB cord on power supply or computer USB port to
enable the batterie detection, this process It is writed inside the user
manual.

Regards.



Le lun. 18 janv. 2021 à 20:58, Ken Sejkora <kjsejkora@comcast.net> a écrit :

> Hi Sigi,
>
> I downloaded the Dislord firmware from the direct download link you
> provided back on 03-Jan-2021 and loaded it into my SAA-2N. Very nice
> having this available. However, when I click the link, it just downloaded
> that specific firmware version. Can you provide a link to a URL where
> Dislord's latest firmware versions are available?
>
> Thanks, Ken - WB0OCV
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> *From: *Siegfried Jackstien <siegfried.jackstien@freenet.de>
> *Sent: *Sunday, January 3, 2021 05:44 AM
> *To: *NanoVNAV2@groups.io
> *Subject: *Re: [nanovnav2] NanoVNA V2Plus4: No power-up with battery
> supply
>
>
>
> try this on your plus4
>
> dg9bfc sigi
>
> Am 04.12.2020 um 04:13 schrieb Tenko46T:
>
> Hello, Sigi.
>
>
> Your proposal went through. Gabu-chan is really an angel.
>
> Of course, it works well now. The V2 Plus4 is my favorite because of its
> beautiful titanium silver finish and the durability of USB Type B.
>
> (But for some reason the Nano-VNA App doesn't take screen capture ...)
>
>
> In any case, I want to back up the main flash, so I will disassemble it
> again and look for SWD pins.
> We have to be careful about static electricity because the air is dry in
> this season.
>
> --
> TENKO
>
>
>
>

HI all , I have the same issue, I am new with my NanoVna, I got it From Aliexpress. When I removed from Cargo packet at first  I tried power swich on but  no powerup, ıItought that battery low , I connected to USB Charger and screen came with smith carht on. Screen came up.

Bu t after few hour recharged I noticed that on off switch is failur. when red led goes down-off , if I tried to get rig on, not opening with its battery,
need to connect to USB charger. I look at in , batter is full around 4 volt. but on off switch has not any 4 volt at center point.  Switch is fonctionnal when USB charger connected.
After reinstall battery, I plug in out USB cabel mni time result: no power-up.

I am Using with external powerpack but not so useful.
Looks like hardware issue. Do we have electronic circuits of SAA-2N

Need help What can I do for this issue.
Regards
TA1D Kadri