Hantec DSO 4102C repair advice needed - Page 1
Forum section: electronics / repair

author: jstbrowsin
author_rank: Newbie
timestamp: December 04, 2018, 08:52:38 am
content: Hi guys, longtime lurker first time poster here and hoping you can help me get a positive result from this disaster. . .tbh I’m hoping it's an IIC error although I seriously doubt it.( IIC = idiot in chair)Anyway I bought on of these scopes recently but the problem is I suspect it has blown inputs possibly from over voltage from previous user but have no way of finding out due to the fact that I bought it from a secondhand dealer who has graciously offered to pay for the repairs if it is feasible. The self calibration mode freezes at step 12 outputting error 0x100 . Manual square wave calibration produces no wave even when pressing auto set! Am I missing something here or have I bought a non working scope?The only advice I got from local Hantek dealers was let it run for 30 mins before doing self cal and that was after they spoke to Hantek overseas haha. . .I did that but still got the same result. I also upgraded to the latest firmware . . .same problem. . Any idea’s please?I have been servicing and repairing musical instruments (amplifiers, mixers, P.A systems, keyboards etc) for well over 15 yrs now so I know my way around PCB’s and SMD devices if I need to fix it.Again thanks in advance for any help you can throw my way.Trevor

author: jstbrowsin
author_rank: Newbie
timestamp: December 05, 2018, 05:09:01 am
content: Bump! ...44 views and not one comment??

author: vk6zgo
author_rank: Super Contributor
timestamp: December 05, 2018, 06:22:08 am
content: Do you have another Oscilloscope (no matter how grotty), to look at it with?If you do, you will probably be able to check the "blown inputs" idea.If the signal makes it through the analog input circuitry, & appears at the input to the ADC, then your assumption is incorrect.If not, you will be right.(or there is no DC power to the analog devices in that circuitry)If you don't have another 'scope, you can maybe apply some reasonably high (a volt or so) input voltages & see if you can see them with a DMM at the same point referred to above.As you probably can't tell if the thing is AC or DC coupled, it's probably best to try with both, with the DMM set to the appropriate range.At this point,I might add that I have never repaired a DSO, but I have fixed analog 'scopes, & some other types of devices with mixed analog & digital circuitry.

author: tautech
author_rank: Super Contributor
timestamp: December 05, 2018, 06:22:44 am
content: Quote from: jstbrowsin on December 05, 2018, 05:09:01 amQuote from: jstbrowsin on December 04, 2018, 08:52:38 amWelcome to the forum.That ^^ rings alarm bells for me.The probe cal output should runallthe time when powered.If you are to dive into it the PSU is the first thing I'd check.

author: jstbrowsin
author_rank: Newbie
timestamp: December 05, 2018, 06:44:32 am
content: View Profile Personal Message (Online)Re: Hantec DSO 4102C repair advice needed« Reply #4 on: Today at 05:42:57 pm »ReplyQuoteModifyRemoveThanks for your advice. I have a digitech DSO and an analogue scope too so I'll check it out later on.Anyone know where I can find a schematic for this please?

author: tautech
author_rank: Super Contributor
timestamp: December 05, 2018, 06:54:19 am
content: Quote from: jstbrowsin on December 05, 2018, 06:44:32 amThere might be a RE'ed one somewhere in the forum archives, have a search. BTW use the Search button not the box.

author: jstbrowsin
author_rank: Newbie
timestamp: December 05, 2018, 07:02:20 am
content: Thanks for your welcome, advice and tip Rob. 😊

author: tautech
author_rank: Super Contributor
timestamp: December 05, 2018, 07:03:35 am
content: Quote from: jstbrowsin on December 05, 2018, 07:02:20 amYou might find something in this thread:https://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/

author: jstbrowsin
author_rank: Newbie
timestamp: December 05, 2018, 01:56:27 pm
content: Ok so I stand corrected. We have signal all the way to input of ADC, so no blown input bugger! All voltage rails are at correct voltages at PSU also.where to from here now? or is this where I let it go and get my money back?Cheers for your help so far guys

author: tautech
author_rank: Super Contributor
timestamp: December 05, 2018, 06:39:19 pm
content: Quote from: jstbrowsin on December 05, 2018, 01:56:27 pmBecause there is no probe cal output it leads me to think there's a OS/SW/FW problem or possibly a cracked PCB, maybe from being dropped. You might get lucky and spot something easy to repair/solder however be prepared to send it back.You do know where to get a working DSO !

author: jstbrowsin
author_rank: Newbie
timestamp: December 08, 2018, 01:47:26 am
content: UPDATE: Believe it or not it’s working now! I decided to open it up one more time (for whatever reason I can’t really remember because it was about 3am) but the thing is after checking the rails again I noticed that one of the data ribbon cables wasn’t seated properly, so I seated it back in place and popped the lid back on and fired it up. . . we have traces and self cal passed too!! Winner winner chicken dinnerThat was until the next day . . . self cal error 0x702Any ideas on that error code please guys?

author: tautech
author_rank: Super Contributor
timestamp: December 08, 2018, 02:12:32 am
content: Quote from: jstbrowsin on December 08, 2018, 01:47:26 amNope.PSU voltages all to spec ?Have you hit the default button....resets everything back to factory.

author: jstbrowsin
author_rank: Newbie
timestamp: December 08, 2018, 10:01:47 pm
content: All voltages to spec and I’ve hit the default button numerous times but no changes.

author: tautech
author_rank: Super Contributor
timestamp: December 08, 2018, 10:10:16 pm
content: Quote from: jstbrowsin on December 08, 2018, 10:01:47 pmSo it operates OK but the Self Cal returns an error ?Both channels measure the same on all ranges ? Just amplitude really needs be checked.Oh, and BTW, inspect the input stages for over voltage damage.Sounds like some sort of SW corruption or the internal Cal values have been lost.....but that worked....once !Have you found a Service manual with the Cal procedure ?

author: jstbrowsin
author_rank: Newbie
timestamp: December 09, 2018, 11:33:13 am
content: It operates ok yes and yes self cal error.Both channels measure the same. I thought the process of tracing the signal to ADC eliminated the over voltage theory. I didn’t see any over volt damage, but then again I never checked the underside of the board. . . I would’ve done that however if the signal didn’t reach the ADC.I agree it SW corruption was my thought too after signal input test. No service manuals around that I can source anywhere. . . unless some kind soul here knows of one???