Recent Posts

21

Projects, Designs, and Technical Stuff / Re: Vacuum Fluorescent Display Driver

« Last post by floobydust on Today at 03:12:07 am »

I don't see G12, G5, G2 being enabled at all and G1 signal looks scrambled with four extra pulses, offset in time as well. The shift-register looks defective 

22

Repair / laptop Acer swift SF314-41 Repair

« Last post by OvO on Today at 03:07:45 am »

my laptop has a weird problem. it has a power on issue.
Once the laptop has been powered on, it can restart/ wake just fine on battery power or Adapter, ONLY If i have not closed the LID/LCD even once.
If i have closed the LID /LCD (even momentarily). it will not power-on/ wake-up on battery power no matter the battery percentage.

but once i open the LID and connect it to the adapter (even momentarily) it will wake up gain and I wont experience any issues till i close the LCD.

i do not know where to look for repair.
help

23

Metrology / Re: Ultra Precision Reference LTZ1000

« Last post by floobydust on Today at 03:04:02 am »

I found pictures of the glass balls in ADR1001 Richi's Lab die shots but do not see them in the LTZ1000.
Could not find die shots of the LTZ1000A die attach. I would assume it's the same so the PCN is in error 

24

FPGA / Re: A FPGA Audio System in raspberrypi size and open source later.

« Last post by antercreeper on Today at 03:00:59 am »

The current is too small for 8millohms shunt resistors(and the solder can also add some resistors). i am sure just millamps, and I can't measure it very well.
for thermal camera, it is as cold as the ambient...
tips: max is 6 amps, 6*8=48millvolts

25

FPGA / Re: A FPGA Audio System in raspberrypi size and open source later.

« Last post by antercreeper on Today at 02:57:42 am »

Sorry for my bad English  :'(

I use TMP435 to monitor the diode of the FPGA and 1. trigger reset of your design while too hot 85 degrees 2. cut the Power while overheated, maybe 100 degrees.

26

Buy/Sell/Wanted / Re: SALE (AU/NZ): Multicomp Pro MP710086 (Owon P4305 rebadge) at element14

« Last post by EvgenyG on Today at 02:50:45 am »

If you are interested in it, perhaps check the manual and some reviews. I'd want to know if it had good controls and was easy to set voltage and current.  Sometimes power supplies with a single voltage knob and single amp knob per channel can be tricky to set precisely (if that is important to you).

Looks like it has 1 turn potentiometers which means coarse setting for Voltage/Amps. I was thinking about upgrading from TENMA but now I'm thnking, even though the build quality would be much better, the digital V control and the ability to lock front panel is very important to me.
The analog pot with 10 deg per volt setting is too coarse, one silly mistake and magic smoke comes out your DUT Price is a bargain though.

27

Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement

« Last post by dj_holmes on Today at 02:40:41 am »

Oh wow so the normal 74HC4046 is better!?!

SN74LV4046A  Optimized Power-Supply Voltage Range From 3 V to 5.5 V

28

Microcontrollers / Re: A couple questions about Milk-V Duo boards

« Last post by brucehoult on Today at 02:40:05 am »

More progress today:

"Daniel aka CyReVolt 🐢: Transferring code to the CVITek 1800B worked with my tool. There was no output on the UART though. I'll see if the SRAM address is different, which isn't described in the manual. UART0 seems to have the same base address per the manual."

"plat/cv180x/include/platform_def.h
296:    #define VC_RAM_BASE 0x3BC00000 // Shadow_vc_mem"

"Daniel aka CyReVolt 🐢: aha aha - 0x3BC00000 - neither "VC RAM" nor that address is mentioned in the manual"

"Daniel aka CyReVolt 🐢: THAT WORKS! VROOM VROOM! 🥳"

"I have now successfully run my own code on
- Duo (CV1800B)
- Duo 256M (SG2002)
- Duo S (SG2000)

The CV1800B has its SRAM at a different base address.
UART0 is mapped to the same address for all three."

His "own code" is written in Rust. Blergh for some people, ++ for others :-)

A note on chip names and companies ... Sophgo bought Cvitech a year or two ago, so CV1800B and SG200* share lineage.  Also, a well informed Chinese person on Telegram said a couple of days ago that Sophgo and Radxa are parts of the same company, or fall under the same umbrella company (Bitmain?). I just found this repo, which lends support to this: https://github.com/radxa/bm-bootloader-arm64

29

Beginners / Re: Replacing SRAM IC with Flash

« Last post by VEGETA on Today at 02:38:15 am »

first time i read about picram thing, definitely weird! an mcu acting as a ram! will look into it for sure.

however, i wanted it to be as simple as possible... meanwhile i got this suggestion (prices are per 100 finished unit):

memory IC: 2.5-3$
counter IC (74HC393): 0.3$
4:16 IC (74HC154BQ): 0.6$
LEDs (16 per unit) example (B1591UY--20C000112U1930): 1.8$ for 1600 pieces = 100 finished units

around 5$

this is without PCB and enclosure.

for enclosure i would go with 3d printing, here is a 3d model for the shell i found: https://grabcad.com/library/nintendo-64-controller-pak-1

how much would this cost for smooth black color? can it be 1$ per unit??

i read about injection molding but using a 3d printed mold... how realistic would this be to get about 1-2$ total cost per unit.?

30

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by DaneLaw on Today at 02:30:22 am »

24h later.....
Unpacked, more pictures will follow in the days to come.
The fact that the display foil is not present and neither are the front dust caps is not a problem, but it was different with the 2104XHD.

As it turned out today, I wouldn't have been able to get one either, despite ordering over 3 months ago.
They sent me their own demonstration device by mistake (hence the missing display foil and dust caps), but I can keep it until a new one is actually sent out.

This Batronix "mistake" where they seem to ship you their own demo-unit as your new retail unit..
Was it you, that asked Batronix why your SDS3000X HD were missing certain new clothing factors, like screen-foil etc, and then they explained you, that "ups we made a mistake  and shipped you our demo unit" or was it Batronix that gave that info without any inquiry and we made a mistake and its only a temporary and you will get a brand new model when its in stock?