Repairing Crossover 30Q5 PRO 30" monitor

[wraper]

Do you have oscilloscope? What model if you do.

[Specmaster]

Do you have oscilloscope? What model if you do.

I have a Iwatsu SS-5710 and also a Hitachi V525, both are 50Mhz.

[wraper]

This board is basically DVI to LVDS converter (bottom IC) + LVDS to DP converter (top IC with heatsink). There are 2 underpopulated LVDS connectors which you could probe to see if there is any signal transmitted by first IC. But bandwidth of scopes is too low. Dunno, maybe they will show something, but at least twice bandwidth is desirable. eDP after second IC is a few times faster so even harder to probe.

BTW as monitor has eDP interface, I think it should be possible to directly connect it to displayport output of PC with DIY connector adapter. Although it still would need power, and will have no backlight control. But as a way to check functionality of LCD panel...
http://www.beyondinfinite.com/lcd/Library/LG-Philips/LM300WQ5-SDA1.pdf

[wraper]

I think you should check if at least both crystal oscillators are working.

[Specmaster]

How would I check the crystals, carefully extract them and test with the scope, signal gen and frequency counter?

[wraper]

How would I check the crystals, carefully extract them and test with the scope, signal gen and frequency counter?

Why would you care about crystal itself. What you should care is if there is oscillation present in the circuit. As if there is none, IC connected to the crystal probably could be faulty.

[Specmaster]

I'm seriously thinking about putting this repair on hold while I tackle some of the other projects that I already have on the go which in turn have been on hold because I have nowhere else for this monitor to stand apart from on my bench which prevents anything else from happening.

So I may have to resort to storing it in the garage for a while I finish off these other projects before I forget what goes where so to speak to say nothing of new items of test gear arriving all the time that needs to be cleaned, checked, re-capped/repaired and shoe horned into my growing stack of test apparatus, many of which are sitting around the room in less then useful locations.

I thank all of those members who have given help and advise so far on this project, especially wraper who I think at times has felt like pulling his hair out because I'm not as up to speed as he is and for those don't know, I'm 69 and the last time I was actively involved in electronics was about 45 years ago so there has been many changes in that time and it takes me a little time to get to grips with them but I'm getting there, so thank you for your support and understanding.

[rancor]

My 30Q5 has gone through two power supplies and gets very warm to the touch. I think they power consumption and heat just come from the old style cold cathode higher gamut backlights. If the display is working the heat is likely to be normal.

[Specmaster]

It seems to be impossible to locate any service information for these monitors on the web and searching for replacement boards draws a blank apart from Aliexpress where you can get replacement T-Conn boards and thats it, why?