Hantek DSO1202B (2 CH, 200 MHz, handheld) calibration failure - Page 1
Forum section: electronics / testgear

author: mcfudge
author_rank: Contributor
timestamp: January 23, 2019, 06:02:14 am
content: Hello,I'm fairly new here and thought this might be the right place to ask a few questions. I searched the forums and was unable to find the same problem already discussed, although I did find there are at least a handful of others here with the same scope and a little bit of discussion about it.My Hantek portable scope DSO1202B (2 CH, 200 MHz, handheld) recently failed self calibration at step 23/38 with error 0x2. The firmware version is 2.01.1 which I believe to be the latest and was preinstalled when I purchased it in 2014. I've sent an email off to Hantek to inquire about repair. In the meantime I'm wondering if anyone else here has dealt with calibration errors with this scope. I can still display waveforms and also take measurements with the DMM, and the results seem to be within the expected performance of this scope.Hantek does not provide release notes and I haven't seen a list of self calibration error codes or any service documentation on this unit. Any ideas? Thanks in advance. A few pics attached.

author: mcfudge
author_rank: Contributor
timestamp: January 23, 2019, 08:38:13 am
content: I ran the self calibration again to time it and verify relay switching can be heard. It takes about 3 minutes to get to step 23 at which point it stalls and consistently fails. You can hear the relay(s) click 9 times from step 1 to 23. After the failure and error message, you just press Menu ON/OFF then continue using the scope.

author: mcfudge
author_rank: Contributor
timestamp: January 23, 2019, 12:37:15 pm
content: Ah, thanks for pointing me to that message. I haven't read the whole thread yet. I checked the relays and did not find a smoking gun. There are two pairs of 2 relays:2x PL-5 signal relay high sensitivity bistable 1 coil latching, 5v coil, 2A/30VDC, 0.5A/125VAC (unmarked)coil resistance 250 ohms, tested ok2x AGQ210A4H High Sensitivity 1 A/30VDC, 0.3A/125VAC DPDT 4.5 VDC Latching 1 Coil SMT Signal Relay (X600, X601)coil resistance 201 ohms, tested okRelays X600 and X601 are active during the self calibration from steps 1-23 and I monitored contacts opening/closing without a problem. The two PL-5 relays appear to measure as expected (coil resistance OK, pins 2,3 are closed, pins 3,4 high resistance/open, and the pattern repeats for the other 3 contacts). I don't see either of these relays being switched by step 23. It is possible they may be switched between steps 24 and 38 but I don't have documentation identifying what happens at each step. I haven't tapped into a UART before but I definitely want to give that a try and get into busybox or whatever is running on it. I'll read up on that thread.By the way, I see bluetooth markings on the board and several unpopulated component markings. Do you know if anyone has gotten a bluetooth mod to work with this unit?

author: mcfudge
author_rank: Contributor
timestamp: January 26, 2019, 09:08:39 pm
content: Thanks to tinhead's instructions in the tekway dso hack thread I picked up a CP2012 UART to USB and have connected to DSOs Linux shell. I ran the self calibration again, hoping to see clues in the console however the software doesn't report anything before or during the error condition at step 23. And the scope appears to continue working normally before and after the test error message (0x2).I did notice that when I kill the dso.exe process a warning message is displayed after watchdog begins restarting the system:[root@Hantek /]# kill 499The system is going down NOWSending SIGTERM to all processes3c2410-wdt s3c2410-wdt: Unexpected close, not stopping watchdogSending SIGKILL to all processeRequesting system reboos3c2440-sdi s3c2440-sdi: powered down.Restarting system.▒*** Warning - bad CRC or NAND, using default environment##### EmbedSky BIOS for SKY2440/TQ2440 #####Press Space key to Download Mode !Booting Linux ...The bad CRC/NAND message is repeated every time I reboot. Is it safe then to assume that message is reliable and I do need to replace the NAND? I'm just not sure if this a quirk of this unit. I read minescumarius message (Reply #2877 tekway-dso-hack) about replacing NandFlash and using H-JTAG and just want to be sure I'm going down the right road here. I've read several dozen messages and have a couple thousand more to go! Hmm, also just read LDTVN's message about replacing the NAND and RAM. The NAND seems to be a common problem.

author: mcfudge
author_rank: Contributor
timestamp: January 26, 2019, 09:28:45 pm
content: Since my model is the 1202B handheld (board version 1002) with sn > 15000 I see that I should run the nanddump command in the shell. I'm still reading the thread to fill in the rest of the blanks with that. And that brings me to jtagging. Which of the 3 possible places on the handheld mainboard (DSO1000H v1.00.2 2012-07) is the correct one for the JTAG pins? Is there a pinout diagram? I have attached a photo and suspect it is the one closest to the 2440 (above and to the right...follow the traces). Is that correct? What is recommended as good jtag hardware? Way back in 2010 Tinhead posted "ARM JTAG cable for H-JTAG" costs 10$, e.g. ebay item 300453556955, but the closest thing I can find today is Wiggler for $24 from Ukraine. If I want a fast and versatile piece of hardware that can be used with this project and many future projects are there are a few models I should consider?Regarding replacing the NAND (K9F1208U0C-PCBO) Where can I buy a couple compatible replacements?Thats it for repairs. Is there a guide to optional upgrades for the handheld? In the attached photo I marked in red some areas of interest:1) LAN pins and unpopulated SMC2) WLAN pins3) SD card pads and unpopulated SMC4) Bluetooth & unpopulated components5) Possible touch screen connector pads6) additional two 10-pin connector locationsIt would be interesting to complete these options, assuming the information is out there.Thanks again for any help here.

author: mcfudge
author_rank: Contributor
timestamp: January 28, 2019, 04:05:27 am
content: Thanks for the NAND tip. I finally read that same message from tinhead in the hack thread here. I guess if I had to replace the NAND I'd just get it from Digikey. Drag soldering with lots of flux would be pretty straight forward, but it seems I may not have to do that now. I popped open both channel covers to expose those 4 other relays (pic attached). I'll keep searching because the calibration failure issue is still not resolved. It has been nice to edit out some of the mistakes in the English.lan and help.db files (Risint, for example, instead of Rising). It also looks like most of my other questions about hardware upgrades are covered in the hack thread too. I see I'm about 8-9 years late to the game with this but I'll catch up quickly. When it comes to jtagging, I think I'm leaning toward a Segger EDU but I still have lots to read.