SmallHD DP7-Pro OLED Monitor Failure

[Smoky]

Hey folks, here's another off-the-wall project

This SmallHD DP7-Pro OLED monitor came amongst a ton of boxes of things from a friend's house-move a few weeks ago.





It's a monitor that mounts to a professional video camera but, as you can see, it included this cool tripod for stationary purposes as well.

Anywhoo, the screen will fade away a few minutes after power-on but, If I wait a few minutes, I'm able to power it back on and the crystal-clear video returns. I used my laptop to feed a signal to the monitor with an HDMI cable. The video quality is as sharp as a laser when it's working.

The monitor is probably over 10 years old since it's described as a "legacy" monitor on SmallHD's website. They sold for over $1500

Is has a fan that runs even after the screen goes dark. Any ideas?

Here's a video I uploaded to Youtube to show you what's happening:



Thanks

[Smoky]

I sent an email to SmallHD about this monitor along with a link to the Youtube video. They replied by saying that they no longer support this monitor but suggested that I load an earlier version of the Firmware (V2.0.4). I did but it made no difference.

I powered the monitor up several times but decided to tap the housing when the screen would begin to fade. It made a difference and brought back the video but it would eventually fade to darkness shortly afterwards. The internal fan would continue to run.

If I leave the monitor off for a few minutes and then power it back on, the crystal clear video returns but then it fades to darkness as before.

It seems to me that something is warming up and then eventually losing connection. I don't think it's the HDMI input because the screen would have gone dark instantly.

SmallHD also said that they no longer carry any parts for this monitor. Here's an updated video of me tapping the monitor:

[amyk]

Looks like a TAB bonding failure. Since it's intermittent you may be able to apply gentle pressure to keep the connection intact.

[Smoky]

Thank you AmyK, I never knew that the connection to the LCD panel was a conductive glue, no solder used for the most part. I watched a few videos as to how the traces are bonded during manufacture. I can also see how easily corrosion can creep into the connection. Since these monitors sit on top of video cameras and used primarily outside, they are made to run much brighter. Which means, they run much hotter.  No wonder why they have internal fans. The video software loaded to these monitors is incredible and, probably, most of the total cost of these things.
 
What I'll do is take this monitor apart and take some hi-res pictures of what I find. Since no visible lines remain after the failures and the video returns crystal clear, maybe it's a "repairable" loose connection? We'll see.

[cozza]

Just a query for repairing one of these monitors. There was a screw loose inside it and it appears to have knocked R31 of the display interface board - the resistor was not found after a thorough look inside.

Was hoping OP could measure the value in the unit he was working on.

[Smoky]

I tried to measure R31 in-circuit for you but I'm getting three different measurements from three different DMM's that I have. Fluke 45 (1M), 8024B (27.7K), and a 107 (75.6K). The resistor would need to be lifted to get it measured properly.

[cozza]

Thank you! At least know I there should be a resistor fitted there. I'll see if they have another DP7 monitor there  so I can remove it and measure the value.

Thanks for having a look!

[cozza]

Hello, a follow up on this repair in case anyone is in a similar situation in future.

I acquired a second monitor and removed the resistor R31 to measure it - 1 megohm.

The missing resistor was not the issue in this case. There is a 30V unidirectional TVS diode across the DC input for reverse polarity / over voltage protection. Replacing this and the input fuse fixed the no power fault.

The main board needs to be removed from the housing to access these components.

Littelfuse SMF30A 200W 30V unidirectional TVS diode.

[Smoky]

Good to hear that you fixed it

That resistor is as small as a grain of salt and I would've boogered things up trying to remove it let alone putting it back without the help of a good microscope setup.

So, out of the three DMM's that I have, the Fluke 45 measured the resistor in circuit correctly. I wonder if that is in all cases?

[cozza]

I tried measuring it in circuit with a Fluke 177 and it gave very different readings with the probes reversed. It's part of a voltage divider network to ground and the mid point goes to a pin on the large IC on the board, so this would have affected the reading in circuit. It was good to know that it was supposed to be fitted for follow up, thanks.

Tiny 0402 parts. I was afraid I would stuff it up as well!  It seemed to be glued to the board and was pretty difficult to remove.

I'm not sure what effect the missing resistor had on the unit - I did have it very precariously set up and balanced for a test after fixing the DC fault, before I replaced it. The display panel was upside down and I could see a boot logo so it was operational  without it. Some kind of bias for the video processor, but I'm not sure what effect it had. The were shooting with it before the dtap power connector was accidentally reversed.