Re: Creep Corrosion on PCB's

I too have seen this in a Synology DS412+ and it's replacement DS415+, took approximately 2yrs from new to failure. I have also seen it in a WD hard drive enclosure, searching the internet I found this paper that takes about it in extreme situations.

[url]https://www.researchgate.net/publication/290158827_Creep_Corrosion_of_Lead-Free_Printed_Circuit_Boards_in_High_Sulfur_Environments[/url]

Pictures of Synology and HD enclosure are below. The thing I don't get is where the sulfur is coming from, possibly the rubber mounts?...

Re: Viewsonic N4785P TCON Issue

Couldn't find the datasheet for the i7868A, so I figured I would try a AS15, waited a month for an ebay special, soldered it on. This is what I got, also it got really hot fast, so it would seem they are not pin compatible to the i7868A. (I have since ordered a i7868A). I soldered the AS15 thermal pad by hitting the bottom of the PCB with a 250W soldering gun, seemed to work ok....

Re: Viewsonic N4785P TCON Issue

Cut the legs off the IC with a razor knife, swept the legs away with soldering iron. Had someone hold the IC and hit the bottom of the PCB with a microtorch. Everything came away easy. Seems like this chip was poorly soldered to the thermal plane, possibly why it failed....

Re: Viewsonic N4785P TCON Issue

Tom you are correct, I took VDD on the PCB to be AVDD and looks like on my board it is simply labeled VDA, it measures 13.7V. (attached)

The gamma IC is an i7868A, which appears to be an intersil chip, but I can't find any datasheets on it, does anyone know if an AS15 is pin compatible?...

My viewsonic went all bright white / negative, so after reading here it looks like a TCON issue, I measured all the gamma voltages and other voltages. I used the spreadsheet made by tom66 and it seems the voltages are all out, AVDD (3.27), Vcom(1.63), Von(0.7), Voff(2.48). Vin seems a little low (11.5V) Is there any further way to troubleshoot this, or should I just board replace?

Thank you....

Re: AS15-G Pinout schematic?

Try and cut the pins off the IC with a razor knife or side cutters if you can, then just wipe all the pins off with a soldering iron. I find if you are careful this will work way better.