UNI-T UT61E just stopped booting up - Page 1
Forum section: electronics / repair

author: boson6
author_rank: Newbie
timestamp: August 04, 2017, 12:21:55 pm
content: Hi,i think my UT61E just died last week.After switching on the display goes on for a second and then blurs out.There is no selftest beep this far.Akku checked btw.I had some similar problem two months ago but in that case it was just an small part of plastic under the range switch.Any suggestions?

author: retiredcaps
author_rank: Super Contributor
timestamp: August 04, 2017, 04:30:27 pm
content: Quote from: boson6 on August 04, 2017, 12:21:55 pmDid you change or try a fresh battery?

author: Nusa
author_rank: Super Contributor
timestamp: August 04, 2017, 05:34:18 pm
content: Akku is German for battery, so yes he checked it.Open it up, look for something obvious. Do all the range settings behave the same?

author: Lightages
author_rank: Unknown
timestamp: August 04, 2017, 06:39:43 pm
content: It might have gotten zapped with static electricity.

author: boson6
author_rank: Newbie
timestamp: August 04, 2017, 07:01:27 pm
content: Quote from: Nusa on August 04, 2017, 05:34:18 pmThat's right. accumulator = Akkumulator short Akku = rechargeable battery = wiederaufladbare BatterieQuotenothing obvious. all parts there, nothing changed, no damages as far as i can see.yes, all ranges are more or less the sameQuote from: Lightages on August 04, 2017, 06:39:43 pmit was unconnected when i switched it on and after i had switched off the last time on my desk. So self-destruction is nealy the only way.

author: ModemHead
author_rank: Frequent Contributor
timestamp: August 04, 2017, 07:44:19 pm
content: Random segments coming on at power-up and then fading out suggest to me the processor is not running at all. If you have a scope, check for oscillation at the crystal. Also, checking the current draw from the battery can indicate how badly things are screwed up. The unit I have draws about 2.3 to 2.4 mA in VDC mode.

author: Refrigerator
author_rank: Super Contributor
timestamp: August 04, 2017, 08:17:08 pm
content: could be that the processor is browning out, try hooking up a power supply to the battery terminals.

author: retiredcaps
author_rank: Super Contributor
timestamp: August 04, 2017, 10:41:43 pm
content: Quote from: boson6 on August 04, 2017, 07:01:27 pmAs you might have guessed by now, I know zero German.

author: joeqsmith
author_rank: Super Contributor
timestamp: August 04, 2017, 11:30:45 pm
content: The nice thing about these cheap meters, you can just toss them and get another. As lightages mentioned, UNI-T in general do seem sensitive to ESD.

author: boson6
author_rank: Newbie
timestamp: August 05, 2017, 12:43:46 am
content: Quote from: ModemHead on August 04, 2017, 07:44:19 pmthe question is where to grep the signal because the crystal is bound directly to the ES51922http://2.bp.blogspot.com/-vqSsIf0wRvk/Vhsc1w-mS0I/AAAAAAABOnY/XRJxL-o-u4A/s1600/ut61e-s.jpgQuotethe Current draw is 1 to 1.2 mA in VDC Mode.Quote from: retiredcaps on August 04, 2017, 10:41:43 pm^^ but you learned something new. In the most cases the words in german are not that much different.On the second view i had seen that on my old multimeter resistor R17A isn't populated. looks a bit like it was once.but the boards are in different revisionsmy old one defect ->https://abload.de/img/img_3336l8u2e.jpgthe new ->https://abload.de/img/img_33534dud4.jpg(the most changes are just in the layout not the circuits itself parts switched from back to front side ...)

author: joeqsmith
author_rank: Super Contributor
timestamp: August 05, 2017, 05:25:10 am
content: Pin 106 OSC2 is the drive side.

author: cdev
author_rank: Super Contributor
timestamp: August 05, 2017, 07:06:30 pm
content: You probably already tried this, but, whenever I run into a problem like that, I always try removing the battery, letting it sit for an hour or so, without power, then putting the (checked) battery back in.This is very strange that that would happen without your having been doing anything when it happened.

author: boson6
author_rank: Newbie
timestamp: August 08, 2017, 10:16:09 am
content: Quote from: joeqsmith on August 05, 2017, 05:25:10 amThe question wasn't about the measurment pins, else i can probe it directly at the crystal, it was more about the measurement in the circuit because there is no clk out pin.I had concerns that the probe would change the oscilation of the crystal and indeed the measurements i had taken were just garbage everything between 50 Hz and 1 kHz but could be my fault measurement.So i just ordered a couple 4 MHz crystals. And what should i say? I got them today and switched the crystal for testing ^^ and my UT61E is back to life.So thx for the hint with the crystal.

author: ModemHead
author_rank: Frequent Contributor
timestamp: August 08, 2017, 12:49:18 pm
content: Excellent! Suggest affixing the new crystal to the board with some adhesive.You are correct to be wary of hanging extra capacitance onto a crystal. It can kill the oscillator, but in practice I've found a 10x scope probe is okay for a go/no-go check.

author: boson6
author_rank: Newbie
timestamp: August 08, 2017, 06:27:07 pm
content: Don't panicThe crystal was just solderd for an quick test. It's now in the proper position like the one before.