Voltcraft VC890 with very low light  - Page 1
Forum section: electronics / repair

author: nenea dani
author_rank: Regular Contributor
timestamp: September 19, 2019, 06:01:26 pm
content: Hi colleagues,I have a Voltcraft VC890 that has gathered about 2 hours of operation in 3 years. Suddenly the light OLED decreased very strongly even at the maximum level. I totally reset it, I changed the 9V battery and the button battery inside. It is no longer under warranty. I wrote to Conrad and they told me to take him to a repair shop in my town. An obvious joke. As I am the workshop, here at the end of the world , I opened it and do not know what to do. Otherwise it works excellent. I lost the CD that came with it which probably had some software . Any advice is good.

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: September 19, 2019, 08:42:18 pm
content: Some internal pictures would be nice to know further what could be going wrong.

author: JFJ
author_rank: Regular Contributor
timestamp: September 20, 2019, 11:04:17 am
content: Quote from: nenea dani on September 19, 2019, 06:01:26 pmIf a quote from Ridley Scott's Blade Runner movie - "The light that burns twice as bright burns half as long..." - applies here, then the only course of action may be to replace the OLED display. An EEVblog thread that discussed the longevity of OLED displays, mentions a 'Storage Life Time' of 20 000 hours:https://www.eevblog.com/forum/projects/oled-storage-lifetime/

author: nenea dani
author_rank: Regular Contributor
timestamp: September 20, 2019, 06:09:22 pm
content: There is a G23F128 controller that leads to the COF just like in an LCD TV. I would like to buy this COF which is common body with the display. I can't find it. 100037401n H 2 is written on the back of the display. On the display connector I find on ceramic capacitors: 3.3V; 12.66V; 3.5V cc .However, I'm thinking of a software alteration. I'm attaching pictures.

author: TurboTom
author_rank: Super Contributor
timestamp: September 21, 2019, 09:45:05 am
content: I had the same meter with exactly the same problem. Display gradually faded so it was barely readable. Finally, having taken some measurements and done some reading on other meters with OLED screens, I narrowed the problem down to the display itself. Sent Conrad a spare parts inquiry only to receive after a very long time the reply that the display isn't available as a spare and they offered me a new meter at a reduced price, but still way too expensive when having to expect it will go bad again within a few years down the road. I then searched the well-known Chinese sales platforms to source a spare directly and even found a company that offered exactly the same model, unfortunately they were sold out and the seller didn't expect to get re-stocked. So I searched for similar displays with the same controller and electrical connection and finally found one that looked promising. Considering the price, it was a no-brainer. So after the "replacement" finally dropped in, I installed it in the meter. The display lit up nicely but showed only unreadable nonsense. So much for the same controller chip...After some more time with the disassembled meter consuming valuable space in the epic mess of my worksop, I decided I already spent way too much time on that piece of crap and disposed it in the dumpster, leaving a satisfying feeling finally...I can only recommend -- don't waste your time on that POS and learn something from it.Cheers,Thomas

author: nenea dani
author_rank: Regular Contributor
timestamp: September 21, 2019, 10:49:12 am
content: I am not a specialist in measurements but I think it is a precise device and I use it as a frequency meter. I have a divider from 12GHZ with 2 ICs and I look at this VC890( 60Mhz maximum) . That's just what I do with it. Unfortunately, I also lost the optical cable. I have a VC820 that has been working perfectly for many years and I think the optical cables fit, although I think it needs a serial to USB converter. I will try to find an optical cable to use on my laptop. I also wrote to Voltcraft which I think is kind of Conrad two months ago, but it seems like the site is gone. I have no shortage of measuring devices, but it really only lasted for 2 hours. What I've noticed is that when I connect it to the AC domain to a DC source (SMPS), I see if it's a ripple. This trick does not go very well with the tru rms devices of the same cheap class.

author: TurboTom
author_rank: Super Contributor
timestamp: September 21, 2019, 02:50:41 pm
content: I may still have the USB adapter for the VC890 somewhere. If it turns up, and you want it, it's yours. I may also still have the software but I think it's also downloadable from Conrad. Shipping within Europe as a letter shouldn't be much of a deal...

author: nenea dani
author_rank: Regular Contributor
timestamp: September 22, 2019, 09:10:01 pm
content: Quote from: TurboTom on September 21, 2019, 02:50:41 pmIf you find this one I am interested in buying it. Thank you for your attention . For now I have download Softvolt Client from Conrad.

author: MilanM
author_rank: Contributor
timestamp: December 25, 2019, 09:35:24 pm
content: Hello,Can you guys check out my topic?I would really appreciate that!Thanks in advance !

author: shakalnokturn
author_rank: Super Contributor
timestamp: December 26, 2019, 01:54:13 am
content: https://www.eevblog.com/forum/repair/voltcraft-vc890-big-current-consumption-180ma/How much does an OLED display consume anyway?

author: ottelo
author_rank: Newbie
timestamp: April 22, 2021, 03:41:26 pm
content: Now I have the same problems like you. Very dark display. I found a very similar looking display on Alibaba and ordered one (~31€ incl. delivery and paypal). It's actualy for a Pure Evoke radio that have also a OLED display with this problem.I will tell you if this display will work!https://german.alibaba.com/product-detail/22pin-pure-evoke-f4-oasis-avanti-flow-radio-sirocco-550-1930112704-9919301000-ritdisplay-3121193010-03-oled-lcd-display-screen-60671545961.html

author: nenea dani
author_rank: Regular Contributor
timestamp: April 22, 2021, 09:56:18 pm
content: I tried to measure the current consumed by the whole device by putting a milliammeter in series with the 9V battery. Something went wrong and the processor went short. Now my device has both damaged processor and OLED. I bought a UT 71D and I am very satisfied.

author: ottelo
author_rank: Newbie
timestamp: May 11, 2021, 11:19:23 am
content: Yeah the display works!!!!! Wonderful. Instead of yellow color its now white.https://ottelo.jimdofree.com/vc890/

author: nenea dani
author_rank: Regular Contributor
timestamp: May 11, 2021, 03:50:46 pm
content: Congratulations on your success!

author: peter-h
author_rank: Super Contributor
timestamp: November 17, 2021, 03:02:49 pm
content: I bought this display module, for the VC890 and for the same fault.Unfortunately I was not able to re-assemble the VC890. Lots of little plastic bits fell out. The build is weird. A standard £10 poor quality chinese DVM inside, cheap in every way, cheap crappy open trimpots, cheap mouldings, etc, selling for £160 due to a nice display and good marketing (marketed via resellers who need the much bigger margin of a £160 product). So I chucked the whole pile of bits in the bin, kept the display for when our 2nd VC890 packs up and then I will have another go.Bought a £20 no-name chinese DVM on Ebay which will be just as good.

author: gigatrek
author_rank: Newbie
timestamp: November 19, 2021, 09:08:06 pm
content: Thank you a lot Ottelo.I've buyed the same white display.The new version is quite different from your, there is an adapter included but it could be istalled simply. I have to move two gums from older to newer display. Half an hour and my multimeter works very good.With few Euro i repair an expensive multimeter. The original oled lost brightness during the non use periods, too, my device works as hobbystic device for small time but it loose brightness however.Best regardsSilvio

author: Bluebrain
author_rank: Newbie
timestamp: March 19, 2022, 11:16:46 pm
content: To make the display brighter and crank up the voltage from 13V to 15V (which is within the specs of the display), install a 100k resistor between GND and the step-up regulator feedback pin as shown:

author: peterkos2
author_rank: Contributor
timestamp: April 13, 2022, 05:59:48 am
content: Perfect idea, it's much better now.well thank you