Trying to repair this OLED display... - Page 1
Forum section: electronics / beginners

author: miguelito
author_rank: Newbie
timestamp: April 14, 2025, 11:27:20 am
content: Hi all!I have a coffee grinder with an OLED display. The display has gradually become dimmer, to the point it is very hard to read now. Except for the dim display the grinder works perfectly.I contacted the grinder maker asking for a service manual. They sent it to me except the manual does not have schematics for the electronic parts, it is mostly a mechanical description of the grinder parts. I presume that the electronics bits are outsourced and they don't really have the info.In any case, I have opened it and taken pictures and I imagine that fixing this issue might be done with some generic information. Specifically, I would first try to understand what I should check - like power lines, power supplies, etc. The programmable controller is a generic Atmel so I gather maybe this is a fairly standard design to troubleshoot. A few images below:Display board images below. Connects to a main board.

author: xvr
author_rank: Frequent Contributor
timestamp: April 14, 2025, 12:09:40 pm
content: QuoteI'm afraid you have to start with the OLED display itself. They originally had a very limited lifespan. Modern OLED displays have aslightlylonger lifespan, but if you have an older grinder, the OLED may be from the early OLED era.

author: squadchannel
author_rank: Frequent Contributor
timestamp: April 14, 2025, 12:30:59 pm
content: If it is a common display, you may be able to replace it.you will find the parts number on the back of the oleds. Do not use alcohol or other solvents. The letters will disappear.

author: miguelito
author_rank: Newbie
timestamp: April 14, 2025, 06:14:42 pm
content: One interesting thing I saw some time ago: I purchased the replacement display board ($380!) and tried to install it. It turned out that the only replacement part that one can get is from a v2 version of the same grinder (same name but at some point the innards changed a bit). What happened was this replacement did not work, but it did light up, and it looked as dim as the one I had in place (which was not as dim as it is now).My takeaway was that maybe it was not the display itself but possibly a power rail that has become noisy (eg a bad cap). However, not having any schematics means I don't really know what to check for.Maybe the next step is to go in with a voltmeter, as voltages can't be too crazy - I can find a data sheet for the ATMEL controller.I will also try and find the OLED display part number.

author: miguelito
author_rank: Newbie
timestamp: April 14, 2025, 07:17:35 pm
content: I just did a couple of checks. Connector to display board has 4 lines: a 5V line with no meaningful ripple; two data lines; and a ground. Seems very reasonable, I don't think a cap is at fault here. You can see how dim the display is below.Using hot air I was able to release the display from the blob of hot glue holding it. The part number can be seen in the pic below. I searched around but I cannot find anything with this part number. If any of you guys know how to find info I would appreciate it.Thx!Miguel

author: macboy
author_rank: Super Contributor
timestamp: April 15, 2025, 05:21:22 pm
content: The microcontroller datasheet is easy to find,ifyou know what to look for. In this case, it is marked "ATMEL MEGA128A" so the chip's part number is "obviously" ATmega128A. Search that part number and you will find it right away. Imagine at all the money they saved not printing the extra "AT" on the chip.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 16, 2025, 02:20:30 am
content: the problem on this lcd is the very wide flex ... and you miss the backlight it seemssearch the ic part number who seems shaa written on it, try to find datasheets, it may be the problem

author: Haenk
author_rank: Super Contributor
timestamp: April 16, 2025, 04:24:00 am
content: Maybe just ask the guys who made this display (I assume it's this company):https://www.scholzsystem.de/index.php/kontakt.htmlHowever it is unlikely the OLED part is still available, but maybe they have a box of old stuff somewhere...

author: amyk
author_rank: Super Contributor
timestamp: April 16, 2025, 04:57:31 am
content: Does this say SSD1351U? Does it have 39 pins?If so, that's a pretty common OLED controller with a mostly-Epson-compatible (S1D15G00) command set. You should be able to easily find a replacement, or as others have mentioned, perhaps a backlit LCD retrofit may be better given the (very) limited lifetime of OLEDs.Edit: this one looks like an exact match? I see the "Solomon Systech" logo in your pictures too, on the other side.https://www.aliexpress.com/item/32837947342.html