HELP - Studio Display 17" LCD 2001 for my G4 MDD

[Classicman]

Hello friends,

I have bought a LCD Studio Display with a backlighting problem. The screen is backlit well only half, only the bottom half of the screen.
The power light display a series of short flashes: a sequence of two short flashes and a long flash.
Apparently it is a known problem of the damaged inverter board. Any of you have repaired the inverter board changing components (i.e. caps...)?
I'd like to fix it because the design of this display is still very current and particular. In my case the conditions of the plastics are nothing short of perfect.
I'm very sorry to keep it like this, damaged...

Thank you all in advance!

 

[tjchris84]

I just picked up a 17" myself and right out of the box, the top half of the screen was darker than the bottom, with the same quick quick slow light.

I popped the back off of the monitor (easy to do, ifixit has a guide) just to visually inspect the caps. Mine all looked good, not leaky and not smelly. Reassembled and nothing changed.

Did you experiment with changing caps? I'm considering swapping the 2 CFL wires to see if the other half dims.

 

[tjchris84]

So I just did an experiment with mine... I flipped the inverter board over and connected the CFLs to the opposite side, powered it up, and the darkness moved to the opposite half of the screen as before.
I was concerned that the backlight bulbs were going bad (it is a 20 year old monitor), but this confirmed that the bulbs are fine and it is, in fact, a bad inverter board.

I have never heard of DV Warehouse, but they have "refurbished" boards here for $69: https://www.dvwarehouse.com/apple/parts/inverter-board/cinema-display.html

My question is, what did they refurbish on them? My 17" inverter board only has 4 electrolytic caps on it, and they visibly show 0 signs of leakage.

Each side has 2 transformers in an IC shaped package (4 in total on the inverter board), and I suspect one of the windings has shorted or failed for one of the 2 for the top half of the monitor. I did a Google search for the part number on the side, but came up with no results.

The numbers for an individual transformer are 22.0415.11 212d

 

[tjchris84]

I bit the bullet and ordered one off eBay for $40 with deep scratches on the LCD. That should make for a perfect candidate for a board swap, and now I'll have some spare parts if needed.

 

[tjchris84]

Well, the scratched monitor has the opposite side dark, and the inverter board is completely different, so I can't swap components to test. I did try interchanging the boards between monitors, and the dark half definitely follows the inverter board.

I tried reflowing the transformers on the inverter board, but it made no change.

 

[beachycove]

That is bad luck, especially as — so far as I know — a board swap is the most practical solution in these cases. It’s what I did with mine some years back, as I could not find replacement components. They do seem prone to failure.

I would look for a known-working 20” ADC display myself. ADC displays tend to sell cheap because, well, they are ADC displays and that makes them redundant. The 20” model is the one I prefer personally, as they offer a good deal more screen real estate than the 17”, which is a bit cramped, without being overwhelming like the whopper 23” model.

 

[beachycove]

And some background reading: https://web.archive.org/web/20070821191206/http://www.apple17inchlcddisplay.com/

 

[tjchris84]

Yeah, I came across that article too... I had one of these back in the day and wanted another one, but it's just not in the cards I guess... I think they were over driving the transformers. I was looking at the design of other sizes' inverter boards, and it appears they are all different.

The later revision I have has clearly beefier transformers than the earlier model, but I guess it still wasn't enough to resolve the issue. It was manufactured by Foxconn, the earlier board didn't have a recognizable manufacturer silkscreened on the PCB.

 

[s_pupp]

Re: DV Warehouse
I‘ve purchased from them multiple times over the years, and have had only good experiences. They are among my preferred suppliers of Mac parts.

 

[gheem]

I have the same issue with my 17 inch studio. I actually got the inverter from DV Warehouse and after the swap I have the darkness at the top so no change with a new inverter. I have not flipped the connector yet to see if the CCFL is shot yet but I guess I’ll try that next.

 

[tjchris84]

Re: DV Warehouse
I‘ve purchased from them multiple times over the years, and have had only good experiences. They are among my preferred suppliers of Mac parts.

Thank you for the suggestion. I may give them a shot.

I have the same issue with my 17 inch studio. I actually got the inverter from DV Warehouse and after the swap I have the darkness at the top so no change with a new inverter. I have not flipped the connector yet to see if the CCFL is shot yet but I guess I’ll try that next.

Yeah definitely try connecting the 2 sets to the opposite sides of the board. I was surprised when the opposite side came to life and the dark half moved. I was sure it was aging bulbs until I tried that.

 

[gheem]

I’ll give it a shot and let you know. I also have the 2 short and one long lights so I automaticity went for the inverter, caps look ok, etc. if the upper CCFL is ok, then the logic board or cabling has to be the issue. Interesting puzzle. I have another good 17 inch so I suppose I could swap parts out of that one to test but I’ve never cracked that one open so do t want to unless I have to……

 

[tjchris84]

I was doing some reading today and came across people using these "universal" CCFL inverter boards to revive older LCD displays. I found one of these for $7.96 on Amazon with free shipping. Here's the Amazon listing: https://www.amazon.com/Richer-R-Pressure-Inverter-Backlight-Supports/dp/B0882HWC1Q

According to the silkscreen on the 17" logic board, the pinout going to the inverter board is as follows:

1. Brightness
2. INV_STAT0
3. Ground
4. Ground
5. Switched Power
6. INV_STAT1
7. Ground
8. Ground
9. +28V
10. +28V

In the Amazon photo, you can see a silk screen VCC, VCC, ENA, ADJ, GND, GND. It says it supports a range between 10-28V, so in theory, maybe this will work?

AliExpress also has these generic replacement boards for 15-24 inch. Here's one for $1.68:

https://www.aliexpress.us/item/2255799884037081.html

The AliExpress listing pinout suggests:
1.VCC, 2.VCC, 3.ON/OFF, 4.ADJ, 5.GND, 6.GND

So, for the Amazon board, I'm assuming ENA is switched power, and ADJ is brightness.

The question is... will the Apple display logic board work without INV_STAT0 and INV_STAT1?

I'm ordering the Amazon one to find out. I have a spare with some deep scratches in it that'd be a good monitor before I blow up my pristine 17 incher.

 

[tjchris84]

Well, the Amazon backlight inverter board didn't work...

I was probing around trying to find which side was ground on the CCFL connectors, and found that 3 were the same, but one didn't seem have a ground. The pins weren't shorted, so I figured I'd try it anyway.

I spliced the connector from the logic board to the pins on the cheapo board, toned everything out and confirmed that it was correct. I then connected them and powered up my Quicksilver with an old Rage GPU and hit the power button.

I heard a chime and the power light lit up on the display for a few seconds. Then when it finally tried to boot, the backlight lit up for a quick fraction of a second, followed by a high pitch whine, then my Quicksilver shut itself off. I immediately disconnected AC mains and disconnected the ADC connector. Luckily, my Quicksilver powered right back up happily with the monitor disconnected.

Now the cheapo inverter board is shorted between the VCC and Ground.

Maybe it was a defective board since one of the CCFL connector pins had no ground that I could find. Maybe it's just crap. But if you like your Studio Display, I don't recommend attempting this.