Studio display M7649 query

[nickbirkby]

Hi everyone, I just bought a 2003 MDD 1.25 with a M7649 display ()marked 2003. The graphics card is a Rage128, which might be non-standard.

The display shows a yellow light at the "on" switch and powers up the G4 when pressed, but it has a black screen.

The graphics card works on another monitor with the VGA out.

Two quick questions- is it risky to test a broken monitor on my other machines cards- it shouldnt zap them right?
Also,  I seem to recall that these displays didnt have a hugely long lifespan/ various issues. It may well just be dead...

 Im just puzzled that the power on still works, though its possibly on a different circuit to the monitor.

I'd appreciate any insights. .....many thanks.   I once fried a card with one of thos big CRT monitors on the tripod legs...so being a bit cautious

[FBz]

May be improper resolution set in control panel for that monitor
OR maybe the monitor IS dead? And I’d have no qualms about
trying it on another machine / card. (It’s not like the M7649 Display
has any voltage of its’ own to send back to the different machine.)

Check this out:
https://www.ifixit.com/Wiki/Apple_Studio_Display_M7649_Troubleshooting

[GaryN]

Also,  I seem to recall that these displays didnt have a hugely long lifespan/ various issues. It may well just be dead...

I'm just puzzled that the power on still works, though its possibly on a different circuit to the monitor.

You're correct. The 17" Studio Display was known to die if you simply gave it a stern look.
The power-on is part of the USB circuit. The front-panel touchswitch voltage is derived from the 25vdc standby that also is the main power for the monitor. It's not unusual for it to be working without a visible display.
The most likely scenario is the inverter board in the monitor that creates AC from the 25vdc to power the two CFL tubes that light the display has crapped out.

Try this: Power up the computer and shine a small flashlight (NOT your phone - that won't work) at the display at an angle. Look closely and you'll probably see the display is working and simply has no illumination. That being the case:

I would say Google "Apple M7649 display inverter" and you'll find more than you ever wanted to know about that board including that it's pretty-much non-repairable, places to buy a replacement ($50–$70-ish) and complete instructions to do the job. EXCEPT:

Since you bought it that way, you don't know if the inverter quit OR if both CFL's burned out - that would be when one dies and the owner keeps using it with the other one cranked all the way up until it quits too. SO:

It will be a safer bet to buy a working display (lots of them on fleabay $60–$150-ish) and keep yours for parts since it probably either has good tubes OR a good inverter AND has a good leg. That's because the way the leg sticks out, they get broken all the time when idiots toss them in a box with a couple sheets of rolled up newspaper and expect them to survive shipping. Unless it's in the original box (almost never) that leg should be removed before shipping (M6 Torx bit) OR VERY well packed to protect the leg.

Or you can just use a VGA monitor……

[nickbirkby]

Thank you so much for the replies- great info!

The story has a fairly happy ending. I tried it on a Quicksilver, and the display came on immediately- albeit with a rather yellowed out colour. I have mac laptop that looks similiar- all washed out with a sort of beige-y yellow tint.

Its workable for sure though. Im going to make a soft synth and reverb (altiverb) standalone machine with my old Korg 1212io so it will be fine for that.

Now I want to find a 23" screen. The screens are quite elegant I think,  although the perspex seems to get quite worn at the age they are now...

[GaryN]

Wow… the mystery display…
The info I provided was based on what you provided. The oddities are:
1) The yellowed–out is the result of well–worn CFT's.
2) The Rage 128 was stock in the Blue & White G4s (Gigabit & Digital Audio)

The most common card in the MDD was the Radeon 9000 Pro with one ADC and one DVI out.
If the display works in another machine and the card VGA works in another machine, the only thing left is that the card's ADC is toast. The flashlight test I described should confirm that by showing no pixel activity.

It's starting to sound like maybe you got a FrankenMDD full of miscellaneous parts. You should, at the very least:
1) Pull the PSU, open it up and blow it out - it's probably filthy and prone to overheat any time AND
2) Remove the CPU card, clean and replace the thermal compound.

If you don't know how, worry not… it's not difficult and there are instructions easily found with Dr Google.

Last, find a Radeon 9000 Mac card. It will provide a better image and you'll be able to drive a larger Cinema display with it.

[IIO]

for weird colors no matter the reason, and for worn out monitors with bad contrast, try the free adobe gamma controlpanel.

[smilesdavis]

i got one for free recently

[nickbirkby]

Thank you for all the replies. I will try the Adobe gamma. The screen is pretty hammered and appears to have a small amount  of coffee spilled INSIDE the perspex case. I was surprised to see it work, but work it does.

Im going to have to hunt for thermal paste.

Speaking of blowing out dust, I occasionally take my power amps to a petrol station and use the tire compressed air blower to blow out dust. It works very well. Should be fine for a PSU/ inside of a case I guess? There can occasionally be slight moisture in those compressed air units, you have to be careful though.

The machine at least had 1.5 gig or ram -that was a big plus. Im trying to track down more PC2700. My herd now has four 2003 1.25 and Im wanting to get at least three up to 1.5.

[IIO]

i´ve never thought of them as sheep herd, but now that you say it....

[smilesdavis]

Thank you for all the replies. I will try the Adobe gamma. The screen is pretty hammered and appears to have a small amount  of coffee spilled INSIDE the perspex case. I was surprised to see it work, but work it does.

Im going to have to hunt for thermal paste.

Speaking of blowing out dust, I occasionally take my power amps to a petrol station and use the tire compressed air blower to blow out dust. It works very well. Should be fine for a PSU/ inside of a case I guess? There can occasionally be slight moisture in those compressed air units, you have to be careful though.

The machine at least had 1.5 gig or ram -that was a big plus. Im trying to track down more PC2700. My herd now has four 2003 1.25 and Im wanting to get at least three up to 1.5.

get a handcompressor, compucleaner i use