Update...
I got a new C5707 (a few actually in case I missed something and destroyed another one). What's interesting now, is I can see the discoloration on the board around Q9. After replacing I powered it up and same thing!! WTH?!?!

I started tracing the circuit back to the input and soon found two 63V 4A fuses, I had originally found a single 63V 8A fuse and found that was fine. But the 4A fuse in line with Q9 was blown. After waiting for mouser to week to fill a tiny order I got the new fuse installed and the backlight stayed lit!!

YEAAAAAAHHH!!!
Lots...

Well this is promising... it's great to have a lot of components to probe on the board. I started with the HV transformers measuring the resistance between the input and output pins, what I noticed is the top side (CN2-CN4) had fairly high resistances (450kOhm) pin 1 and the others. Moving to the other side Cn5-CN7 were all almost 0. Odd so I checked the ESR on the big caps neraby and found, pictures are easier than words, so these are measured ESR values, no surprise the two on the right are equal because they are in parallel...
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Thanks again, right now I'm toying with the idea of i2c injection to see at what point the display cuts off, I know it's on at min brightness and off at max, but where does it go south may help me. I have questions about just wiring in an embedded dev board to the monitor main board and while I think that's safe if running directly off the display's power I still got questions I hope someone can confirm my thinking.... we'll see what the collective says.

There are no electrolytic caps on the inverter, at least none I've seen. I shared a picture before, and I don't see anything other...

Thanks for the reply, yes without a schematic for the inverter board I was not comfortable given I also know nothing about those boards. 🙂 I would have to get some help finding replacements for those transformers who knows if there's a compatible part available today!
I didn't think of checking the transformer resistances, will do once I get it back on the bench.

So the caps like 25-33 would be the HV caps you called out? I could ESR check those, but given their voltage I'll just be able to check similar look similar.
Are the J parts that look like large resistors,...

With a little more digging I found the data sheet for the -04 panel which is still not the -03 version but does provide additional information about the signals to the inverter board. Seems the -03 version has the most wires, but this looks promising!

I was correct with regard to two different grounds, VEE and BRICON would use the single line ground while the 12V "HV" lines are paired with the group of 4 and would explain why I had to connect the board directly to AC ground rather than just use DC ground. I had the BRICON signal backwards lower voltage is brighter, so the...

Little update because I'm looking to move this to the side for a while, I was able to confirm the screen does have an image!
I'm also sharing a video of the display being switched on to demo the dim backlight behavior. I hope I can share .mov file!...

Hello, I came here after finding some similar questions asked on other monitors and hope someone here can help me get an ancient Viewsonic VP230mp (23" 4:3 LCD) back to working condition.

First a little background, I have a background in computer and electrical engineering, and I'm smart enough to know I know nothing about LCD displays and how they work. For this topic I'm as green as they come.
When the display is turned on the viewsonic logo displays in the uppper left for 2 seconds then the screen goes black, the power LED is green (on) and when a computer is connected...

Hello, new member intro looking to make a long-winded post looking for help with an ancient LCD display (Viewsonic VP230mb). I found this forum after attempts at my regular retro sites (atariage, reddit, maker pro, etc) came up empty. Found users here answering questions I would like to ask... wish me luck!