Need repair advice: 23" Apple Cinema HD ADC backlight/inverter fault, short-short-long LED
I have a clear acrilyc 23-inch Apple Cinema HD Display ADC, model M8536. It gives a perfect image for a while, then the screen goes black and the orange power LED starts blinking in a short-short-long pattern, repeating about every 10 seconds.
Symptoms / timeline:
- Initially it would randomly black out for about 1 second during use.
- Then it got worse and eventually would only show image for a few minutes.
- After being unplugged for many hours it sometimes works again for a while.
- When it works, the image looks perfect: no lines, no color issues, no panel artifacts.
- I also hear a very faint ticking/crackling sound sometimes.
- Lowering brightness to 50% did not solve it.
- A 22-inch ADC Cinema Display works fine on the same Mac/adapters.
Setup:
- Mac mini M4
- StarTech USB-C to DVI adapter
- Apple ADC to DVI adapter
- Also tested with another/NOS Apple ADC to DVI adapter
Repair attempt:
- Opened it up at a repair café.
- The two electrolytic capacitors on the inverter board measured OK for capacitance, but were replaced anyway.
- With the new caps, nothing looked abnormally hot on an IR camera.
- Back home, the display still failed after about 13 minutes with the same short-short-long LED blink pattern.
- Power cycling brings the image back temporarily.
Questions:
Does short-short-long on the M8536 specifically point to the inverter/backlight circuit?
Besides the two electrolytic capacitors, what are the most likely failure points on the inverter board?
Are the inverter transformers known to fail thermally on these?
Could one bad CCFL tube trigger this even if the image looks perfect while it is on?
5 . Are replacement inverter boards or donor parts available / interchangeable with other 23-inch Cinema Display models?
Any advice from people who have repaired these would be greatly appreciated. I really want to keep this display alive.