21" CRT Studio Display Issue

[notcrazy_iminsane]

I managed to get this 70lbs monster home

I got it for my sister to use with her laptop since the screen's going out (It's a PC since we can't afford a good Mac Book yet). The problem I'm having with the monitor is that it won't display anything. She booted her laptop with Ubuntu and it detected the monitor (I think it said "Apple 21 Inch Studio Display) and the power button on the display will turn green, but after that, nothing happens. I tried it with her XP partition and got the same result, except XP didn't detect the monitor, but it detected the extra USB ports. As soon as I can get into her OSx86 partition, I'm going to try from there too

I tried it again on my brother's laptop (Also a PC, but a different model) that ran Windows 7. It detected the monitor, tried to configure itself to use it too, but the display still showed nothing

I'm about to try it again using my laptop that's the same as my sister's, but running Windows 7 and see if I get any results. I'm starting to think either a driver is required (which I'd find odd since any other monitor connected to the VGA port works just fine), or maybe something's lose inside of the display keeping it from showing anything. I've looked up and down the internet and can't find anything pertaining to this issue.

And yes I've tried increasing the brightness. It does nothing at all.

[LC_575]

For compatibility's sake did you try setting the computers in question to a very low resolution with a low refresh rate, something like 640x480 at 60Hz?

I've never encountered a monitor that couldn't display that sans driver.

[notcrazy_iminsane]

I've tried just about every combination available, the first being 640x480 at 60Hz I can hear it change the settings in the monitor, but nothing shows at all. I did some research on this and found that a lot of these monitors died about 6 months after they went out of warranty, but nothing on how to fix it.

[notcrazy_iminsane]

I found a take-apart guide with troubleshooting on it too It only took three days of searching to find it. Hopefully I can find what's wrong with it and fix it.

[notcrazy_iminsane]

Gah. No luck finding what's wrong with this one

I got a 17 inch CRT display with a Blue and White G3 Power Mac I got today. The display that came with it acts like it's about to die. If I turn it on while connected to the computer, the display makes a clicking sound and wiggles around. It's an odd display...

[techknight]

if i could get my hands onto one, i could fix it. Sounds like its missing the cathode drive to the CRT.

[notcrazy_iminsane]

I would love to have it fixed, but shippong the 70lb monster would be so expensive...

The 17" is dead now. Doing the same thing the 21" does. From what I've found on the internet is that it's a specific part that went bad. Like a capacitor, resistor, something of that nature....

[Dennis Nedry]

Did you check the brightness / contrast?

[notcrazy_iminsane]

Brightness and contrast did nothing. It was one of the first things I checked I wish it was a simple fix like that. It would save me the hassle of moving these big things around.

[Theretrogamingroom]

I know that on many (If not all) laptops that have a VGA out port have a button (Usually on the keyboard, mine is F1) that you need to press to make the LCD display to an external video device.

Have you tried this?

[notcrazy_iminsane]

I haven't tried that just yet. Most of the time my laptop automatically sets a secondary display to show what the main display is showing. I've also tried using the display on my B&W G3 Powermac and got nothing on it either.

I still have yet to open the case on it. It seems like quite the hassle to open it without cracking the case, especially since I don't have the proper tools

[techknight]

Sounds like something has failed on the CRT's analog board. I dont have one to fix, or i would explain what to look for and how to fix it.

[notcrazy_iminsane]

Well darn... I just got around to opening the 21" display. I removed all the boards and looked them over. Everything looks to be in order, but I still need to test it with a multimeter (which I lack until the fall semester at my school starts) maybe I could find replacement boards somewhere...

My sister said that the popping/cracking sound the 17" display would make came from an area around the yoke assembly. That's a little bit of info that throws me off. I know that the video board is right behind the yoke, with a smaller separate part connected directly to it. I've heard that there could be a problem with the deflector board from my Internet research but, being the wuss I am, I'd prefer not to mess with the anode or the transformer. Sure the 21" hasn't been used or even plugged in for a few months, but I know that they can still hold a charge.

[notcrazy_iminsane]

Just my luck. I did more research, and as it turns out it IS the transformer that's fried. I'll have to look around and find a new one... Wonderful.

[techknight]

How do you know? Did you physically pull out the transformer and look for shorted turns with a ring tester?

Did you put a narrow pulse through the transformer and checked for winding-to-winding bleedovers/shorts?

I'm assuming the flyback? if so, you could pulse it and measure the outputs of both the primary HV and the secondary voltage for focus/screen. Ive seen these fail in AOCs causing loud SNAPs at turn-on, monitor eventually fails with a shorted HOT. (horizontal output transistor).

You could run to your neighborhood hardware store, or harbor freight and buy a cheapo DMM for $5 to $10 dollars. Then test the output transistor on the flyback for shorts, and test the transistor on the SMPS supply. the HOT will always read a short/low ohms between B to E, because there is a pulse driver transformer to deliver maximum current to the transistor. but you should NOT have shorts from C to anything.

[notcrazy_iminsane]

I'm just assuming it's the flyback right now. Majority of the sites I dug through point the snapping and eventual death from the transformer failing. I'll test it soon, and hopefully it will be a quick fix. If not, I pulled out all three boards and will test every inch of it.

I might actually have use of a multimeter soon to test it. I just gotta find the thing...

Edit: I manned up and discharged the CRT in a method that was probably not the smartest, but managed to get the job done. I'd advise against my method of unhooking the board, removing the anode, running outside, and rubbing said anode on the metal shed outside. Oh the joys of not having my tools at home.

[techknight]

snapping could be caused from anything. poor HV regulation, bad Focus/G2 block, etc... Eventually the spike takes out the HOT which leads to the fail.