OLED SSD1306 128x64 - internal booster died?

[Stephanie]

I have two of these 128x64 OLED screens, and on one of them the screen suddenly went dark on me. In testing I noticed that VCC was reading only about 2.5 volts, where it had been reading closer to 9v originally. I checked my other OLED (which has a bit of a dim screen) and it is showing only about 5v on Vcc.

If I wire a 9v battery with ground to my project ground then connect the positive terminal from the 9v to Vcc on the 'dead' OLED, the screen jumps to life nice and bright. Then when I remove the 9v, the screen is 'dead' again.

Both my OLED screens are wired into projects so they are not easily accessible from the back but I am wondering if any of those SMD components on the back would be intimately involved with the on-board booster? If one of them broke off would the onboard booster die but everything else keep working?

Or - hate to say it but gotta ask - is it possible the onboard boosters on these things are a bit on the flaky side? I'm wondering because I bought both of these at different times, months apart, and seeing one 'die' and the other having low output, maybe it's coincidental but it's out there infront of me. For what it's worth, the one that has 'died' is the newer one, the one that works but with reduced output is about 5 or 6 months older.

Thanks!

[adafruit]

hmm, we've never had any issue with the internal DC/DC and they're used in cell phones so they should be fine for long term use, and its the first we've heard of any issues (we've had these oleds for a year or so)

[Stephanie]

My first assumption was a bad solder joint in my wiring but I inspected it all under a good light source with a loupe and it looked ok. Then when I measured the other one and saw it's Vcc was lower than spec that made me think maybe there was a problem.

I decided to remove the dead one but had an unfortunate SLIP! and damaged the ribbon cable so that was the end of that. Once it was out though I turned it over and checked the SMT parts on the back, they were all firmly in position.

What I did notice, comparing the dead one against the working one, is the dead one had a bit of that kapton tape stuff over the ribbon cable contacts. Looking closely (with the loupe, under a bright light) it looked like something was 'wrong' so I peeled the kapton tape back and discovered there was some corrosion along one of the traces.

I haven't had the OLED in or near any moisture, but it has been kind of humid around here lately. I don't know how fast/slow this sort of corrosion would happen, but I'm wondering if moisture did somehow condense under the kapton, could that corrosion have caused the internal booster to fail?

For what it's worth, my other OLED (the older one) did not have any kapton over the ribbon cable or solder connection, and when I closely inspected that, there was no sign of corrosion.

Here's a macro photo of the back of the OLED:


Link to the full-size image.

You can see the corrosion beneath R1 and C4, as well as on the back of the Kapton just to the right. There appears to be more around R4 and C3. You can also see my big horrible Ooops along the ribbon cable. Memo to me, don't use an x-acto knife as a miniature lever. (That's what they make flat-head screwdrivers for.)

After taking the photo, I peeled the ribbon cable off completely and found the corrosion seemed to go under the ribbon cable, so it wasn't just under the kapton. A few of the ribbon cable's contacts were black rather than shiney-brass coloured.

Anyhow, I've swapped my other OLED out of the older project and into the new project so it's up and running again.

Having inadvertantly delivered the coup-de-gras to the poor thing myself, I would not ask for / don't expect a replacement, but I do want to point out this corrosion incase this is something to be wary of.

Cheers!

[adafruit]

thanks for the research note, we'll keep it in mind, although not sure how that could have contributed to the problem :/
email support@adafruit to get a replacement and we'll see whether that one lasts longer!

[Stephanie]

Just an update on this, as I think I know what happened now. I did not ask for a replacement, as per my prior post since I couldn't determine what caused the failure, and I had slipped and slashed the ribbon cable.

I used the second screen I had in another project, but before installing the other screen I did verify that there was no sign of corrosion on it at all, so I knew it was 'clean' going in.

Today, 12 days later, that second OLED failed. The symptoms were the same as the first one; the dc-dc booster appeared to have died. When I removed the screen and examined it, I found signs of corrosion on the back just like I did on the first dead screen.

The project that these screens have been used on is my 'ISEB-6' leather bracer. I suspect that chemicals from the leather (either oak tannins or chemicals from the dye) are leaching out of the leather and attacking the SMT caps and resistors on the back of the OLED. The back of the OLED is the only place where electronic components were directly touching the leather - everything else has a layer of plastic between the circuitry and the leather.

So the good news is that the failure was not because of some flaw or defect in the screens themselves.

As for my 2nd dead screen, I've cleaned up all the corrosion and touched up all the solder connections, and will see if the screen can be saved. If not, I'll replace it again. And either way, this time I'll use something to seal the back, either epoxy or silicone, to try and keep the leather's chemicals away from the screen's electronics.

[nkg]

The internal booster in my SSD1306 has also died. It appears that I have the same corrosion under the kapton. VCC reads ~2.7 volts.

Stephanie, were you able to bring it back to life by cleaning up the pins?