DSO 8060 smells like dead electronics + not booting - Page 1
Forum section: electronics / general

author: duckie
author_rank: Contributor
timestamp: July 09, 2012, 05:53:40 pm
content: I bought my DSO 8060 last year august, and never used it much - sadly i too busy with other stuff. Now i am starting up on electronics again, so i took it out, booted it, measured a pwm signal, shut it down and let it charge the battery. 1-2 hours later, i noticed a smell of burned electronics - it was the DSO. Now it is not booting.It has always been kept in the original bag, and i did not touch inputs/outputs or anything else. It worked all the way up to i shut it down again.Has any one run in to the same issue? My first guess would be a component in the power-supply. I have emailed Hantek, but i doubt they will answer right away, and i assume they will do little to help me.

author: free_electron
author_rank: Super Contributor
timestamp: July 09, 2012, 06:53:17 pm
content: hmm. battery ? been off for a very long time ? probably the battery was so empty that the charging attempt fried the charger. Proper design should prevent that ...unplu the battery and see if it works on the adapter..

author: duckie
author_rank: Contributor
timestamp: July 09, 2012, 08:52:36 pm
content: Yes, it has been off for long, so that could be it. I will wait for a Hantek reply, before taking it apart.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 10, 2012, 01:14:02 am
content: maybe ants infesting inside. shorting electronics.

author: ivan747
author_rank: Super Contributor
timestamp: July 10, 2012, 03:04:03 am
content: Quote from: Mechatrommer on July 10, 2012, 01:14:02 am"Just bash it against the desk and see what comes out"

author: duckie
author_rank: Contributor
timestamp: July 10, 2012, 07:53:19 am
content: Soooooooooooooooooooo.... I found both cause and effect now...Hantek already replied me:QuoteWhen i looked at the supply, it said "Netgear".. Oh crap. I must have packed it down with the wrong supply, and not checked it when using it again. Brilliant. The netgear is 12V, while the charger in the manual says 8.5V.Below is the result. I cannot clearly see it, but looking at the picture, the silkscreen and a similar nearby component, i am pretty sure it is a capacitor valued 100|16V. Nothing else looks damaged, so replacing it could save the unit? Could anyone help me, by linking to a replacement component?If there were some kind of Darwin Award for electronics, i would be a candidate.

author: Psi
author_rank: Super Contributor
timestamp: July 10, 2012, 08:21:29 am
content: Can you post a slightly larger pic of the PCB showing more components?

author: duckie
author_rank: Contributor
timestamp: July 10, 2012, 09:15:18 am
content: More pictures here:http://imgur.com/a/f2VkW- if you want pictures of specific parts, please just say.Rose added this:"If replace C73 still not work, please also try to replace the chip TPS76333."Not really sure where that is placed, but will start with the capacitor.Exceptional support!

author: Spikee
author_rank: Frequent Contributor
timestamp: July 10, 2012, 09:18:24 am
content: Shouldn't there be an over voltage protection in that thing ,or is it the "when something blows , you have to much voltage" ?

author: Rerouter
author_rank: Super Contributor
timestamp: July 10, 2012, 09:19:49 am
content: http://www.ti.com/product/tps76333should look like that

author: duckie
author_rank: Contributor
timestamp: July 10, 2012, 09:35:26 am
content: Quote from: Spikee on July 10, 2012, 09:18:24 amI am also a bit surprised.There are at least two component that have the same footprint as the TPS76333, would have to find a magnifier. No visual damage tho.

author: amyk
author_rank: Super Contributor
timestamp: July 10, 2012, 10:54:55 am
content: Was the power adapter you used a different polarity from the correct one?That capacitor is rated for 16V so it shouldn't have blown with 12V across it, but reverse polarity can rapidly cause such a failure.

author: Psi
author_rank: Super Contributor
timestamp: July 10, 2012, 11:00:38 am
content: The netgear pack may have been unregulated, so could be up to 18V no load.It may have been fine while charging as this would have pulled the voltage down to 12V.But as soon as charging was done the load disappeared and the voltage become to high for the cap.

author: duckie
author_rank: Contributor
timestamp: July 10, 2012, 11:10:22 am
content: Unloaded the Netgear outputs 14.22V, rated 12V.I found the original charger now, and it outputs 9.3V, rated 9V (although the manual says 8.5V).

author: Electr0nicus
author_rank: Regular Contributor
timestamp: July 10, 2012, 11:42:28 am
content: If that cap is part of a switch mode regulator, I will pay close attention, that the replacement capacitor has a low ESR. Otherwise you will get a huge ripple voltage on the power rail, this switchmode regulator is powering. So the oscilloscope won't start either, although there are maybe no other damaged components.How did you measure the netgear supply's output voltage. If you did with a multimeter, then there is the possibility, that the actual peak output voltage is above 16V, because maybe the output ripple is several volts with no load. To confirm this, you'll have to measure the output voltage with a oscilloscope if you have a second one to hand. But pay attention that you don't make a undesired earth connection with the ground clip of your scope. Best you use a isolating mains transformer. Seefor more details

author: duckie
author_rank: Contributor
timestamp: July 10, 2012, 12:59:16 pm
content: Yes, a multimeter is all i got.So what should i replace it with? Like this:http://uk.rs-online.com/web/p/tantal-faststof/6845216/?

author: Electr0nicus
author_rank: Regular Contributor
timestamp: July 10, 2012, 01:24:59 pm
content: This cap looks not bad. It's worth a try. Unfortunately we don't know the ESR of the burned out capacitor. But I think 0.1Ohms is pretty typical for this size, capacity and voltage rating, as you can see in the search results on RS-onlinehttp://uk.rs-online.com/web/c/passives/capacitors/tantalum-solid/?searchTerm=100uF+16V&sort-by=Equivalent+Series+Resistance&sort-order=asc&view-type=List&sort-option=Equivalent+Series+Resistance.The most amount of caps listed there, have >=0.1Ohms ESR, so a 0.1Ohm one should be fine.

author: duckie
author_rank: Contributor
timestamp: July 10, 2012, 01:33:38 pm
content: I mailed Hantek again, they seem to have very very good support.