Promethean Screen - Backlight issue

[cooper549]

Hi,

 

I've got an older Promethean AP6-70 screen I'm having some issues with, its randomly started turning off the backlight for no reason.

 

We've factory reset the board and done some firmware updates as recommended after speaking with promethean support, but unfortunately they now want £2500 to replace the board. Which to me is a little pricey all things considered (I've been buying ViewSonic panels recently and they've been amazing in comparison and these are half the cost so the classroom will get one of these instead)

 

But the funny thing with it is, the backlight will come back on if you press a button on the front, but not by physically tapping the screen

 

We've tried different cables on different inputs too which made no difference, but we can almost time it to the minute that it seems to go out after 30 minutes. All the power save options have been turned off or reset to factory defaults too with no change to the behaviour

 

We've done the old torch against the glass and confirmed it is only the backlight that seems to go off as we can still see videos or the mouse cursor moving when we do this.

 

Has anyone else ever come across an issue like this with their promethean boards or perhaps any other screen and what was your experience or how did you resolve it.

 

Thanks in advance!

[Brax]

I found that with the older prometheans the backlights fail often and it was quite visible when they were on their way out as some of the backlights breaking were brighter than the rest of the board but not enough to be too much of a nuisance for students. We just had them replaced in the end, not worth repairing them. It is pricey but they pay for themselves pretty quick. You could always go for an alternate make? We bought some iiyama boards for some new classrooms that worked really well. The 75" screens used to go for around 1.9k I believe, not sure if they still do but worth having a look and getting a quote.

[cooper549]

The classrooms is going to get a replacement board with a doubt, you're right and its not worth the money to repair it at all. The last few boards I've bought from ViewSonic have been around £1300 to £1900 depending on the model and they do all the same stuff and they've been great so far. Even their management side whilst basic in some respects, is great in the fact its been a one off fee for each board.

 

I only really asked on here because I'd rather know if there's anything we could do/change/replace to just give it its last lease of life before it ends up e-waste. And to be honest, I'll put up with it going dim on the wall every so often so I can replace my own antiquated whiteboard in the office. Heck, I'd even tear the thing apart and see if we could separate the substrate to have a bodged see through screen when it finally dies as its not going to end up anywhere else but the e-waste bin.

[Aprice]

We've recently had a spate of power supply failures in the AP7 70" panels, seems to be a design defect in the PSU. The warranty replacement was pretty good, can take a bit of nudging to try to move it along. Not sure that the Promethean boards are worth the price premium though.

[synaesthesia]

Necro thread time! @Aprice do you recall if those failures resulted in what looked like backlight issues or was it just a dead no-power situ?

Just got an AP7-70 flashing at power on with a very audible sparking. Already organised to swap it out with an older board to get them up and running, but if there's a chance it's power supply I'll be able to fix that for pennies, unlike the backlight

[synaesthesia]

Just in case anyone gets similar, I found the source of the problem. Extremely poor soldering and lovely dry joints

 

Well worth a check if you're frugal/tight/broke. Back off, disconnect everything, make sure you discharge the caps (row of 3 on these). Fresh flux, lovely leaded solder and it'll be good to go again.

Does indeed present like backlights on their way out but the sparking suggested otherwise, and the slight scorchmarks on the protective black plastic covering behind the PSU pinpointed the spots