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Black screen on Power Mac g4

Hi

We have a Power Mac G4. Recently we haver tried to hook it up to a mac calibrated monitor but this is proving to be a problem.

The G4 is booting as normal. The initial grey screen loads up onto the monitor but after that everything goes black.

A friend of ours has checked that everything is working inside the machine correct and has "talked" to the computer but nothing seems to be wrong.

Can anyone help?

Thanks

 
maybe the monitor doesn't support the screen resolution or refresh rate the Mac is trying to use after it goes past the gray Apple screen.

have you tried resetting pram or nvram, have you tried to boot from a tiger install cd to see if the monitor will work that way.

BTW, what brand and model is the monitor.

i haven't ran into this issue before (i might be asking the wrong questions).

can it be a video card issue or driver issue. have you hooked another monitor up to it to see if it does the same thing. have you checked the end of the monitors connector to see if the the pins isn't bent.

 
Last edited by a moderator:
Hi

Thanks for your reply.

I am not sure how to reset the pram or nvram or even what that is. I am a bit of a newbie when it comes to macs.

We have tried booting from the the CD's that came with the G4 but that did not work.

The monitor is an Apple Cinema Display A1081 20" LCD Monitor.

Thanks very much

 
Hi I forgot to, yes it has been working with another monitor before we tried it with this one. We do not have the other monitor available now to test it again. I dont think it is a driver issue or video card issue but I cannot be certain.

Thanks

 
HiThanks for your reply.

I am not sure how to reset the pram or nvram or even what that is. I am a bit of a newbie when it comes to macs.

We have tried booting from the the CD's that came with the G4 but that did not work.

The monitor is an Apple Cinema Display A1081 20" LCD Monitor.

Thanks very much
to reset pram hold the command (the key with the Apple on it)+option+P+R keys as soon as you hear the start sound and keep them held until you hear the start sound 3 - 4 more times. note that you have to hold the listed keys down at the same time

to reset nvram hold the command ( same key as listed above)+option+o+f as soon as you hear the start sound and keep them held until you see a command line. if you dont see it, you can still do it blind

type the following

reset-nvram (press enter/return)

reset-all (press enter/return)

after these commands are entered the machine will restart itself.

does this monitor use a VGA connector or a ADC (Apple Display Connector). it probably would be good to ask you what model of G4 this is, cause there is quite a few different models. some models have a vga output, some have a VGA and ADC output.

EDIT

additional info

if memory serves, the 20" Apple cinema display (LCD) hooks to the ADC output on the video card. and only video cards with 32mb or more vram will drive this monitor, meaning a Rage 128 pro will not be enough to drive this monitor, the video card will have to be a Nvidia Geforce2 MX (or better) or a Radeon 7500 (or better) or a Powerbook G4 with a DVI port using a DVI to ADC connector, also i think it requires OS X 10.2 or better.

if you have the Rage 128 pro it will drive the 15" Apple cinema display (LCD) just fine, but not the 20"

 
Last edited by a moderator:
Hi

I am not sure what the different types of connectors are. Do you know how I would be able to find it out?

The model of the G4 is a PowerMac g4

Thanks I shall try reseting the pram and nvram.

 
all G4's (besides the mini G4 and iMac G4 and laptops) are called PowerMac G4

what i was asking was, is it a Yikes G4, Sawtooth G4, Gigabit ethernet G4, Digital Audio G4, Quicksilver G4, Mirror Drive Door G4.

i am thinking that its either a gigabit ethernet G4 or a Digital Audio G4 466 or 533. since those models could be configured with a rage 128 pro that had the VGA and ADC on it.

so the reason you say it wont work on your Mac is cause it has a rage 128 pro in it, its a rather simple thing to fix ( if you have the money) is to look for a official Apple shipped Nvidia Geforce2 MX, Geforce4 MX, Geforce4 Ti that has ADC on it, or a ATI Radeon 7500 (or above, sorry cant remember the models that had a ADC port on them).

the flashed PC to Mac of the above models of video cards (that has DVI) will be of no use unless you get a DVI to ADC adapter (but that depends if the DVI output works on the flashed card).

if its a Gigabit ethernet G4 it will only have a AGP 2x slot which will limit you in the video cards you can use ( can only use up to the Geforce 6200, and a ATI Radeon 9800 Pro). if its a Digital Audio G4 it will use up to a Geforce 7800 GS (or GTX or GT) and a Radeon 9800 Pro (and maybe higher)

but that depends if you want to buy a video card for it ( you will have to know what model of G4 it is). or sell the monitor and find the 15" model.

if i remember correctly there was someone selling a few Apple shipped video cards that could drive that monitor on the trading post here. i am not sure if he still has them or not. you will have to PM macsane and ask him if he has a AGP Nvidia Geforce2 MX, or a AGP card with 32mb vram that has VGA and ADC on it. i have bought a few things from him and he is a good friend, and a person of his word. it will just depend on if your located in the USA or not.

 
Another bit of helpful information is the specifications on the back of the machine, they should be on a little sticker near the power supply. It'll be a little area about three or four inches wide by an inch or two high. It'll also have the date the machine was manufactured, which will be very helpful for us.

 
Thanks very much guys. I will look at this tomorrow when I get back to the office (where the computer is located) and get back to you all 2moro.

Chantal

 
just for clarification sake

a yikes! has no AGP port ( brown slot on the mother board) its video card is in a pci slot ( white slots) and they are typically 350 to 450 mhz

a sawtooth has a agp port its video card will be in a agp slot and they are generally 350 to 450 mhz

a gigabit ethernet looks like a sawtooth but tends to be 500 mhz other then actually getting the thing on it looks just like a sawtooth

a digital audio is and i might be wrong there usually a dual G4 they tend to have massive heat sinks but i am not too sure about that

a quicksilver is quite easy to reconigse it has an unique new casing with foru ventilation holes just above the floor handle they start at 733 mhz

and lastly but certainly not least a mirrored door drive which is exactly what it is the drive doors are corverd woth something metallic that does mirrors to a degree they are unmistabakle and unmistakable loud too they are always dual G4's and the best G4's you wil fidn this side of a mac mini

 
the Digital Audio comes in both single and dual CPU configs, they mainly can be spotted from their CPU speed, 466mhz, 533mhz, 667mhz, 733mhz CPU's some of them had dual CPU configs running the same speed as the single counterparts.

really the MDD and mini only benefitted from having a 33mhz faster system bus and having DDR ram. in reality the DDR didn't help things at all speed wise, it was more of a marketing gimmick then anything else. cause for one a 167mhz system bus will hardly reach half of the available bandwidth DDR has. also there is some cards not compatible with the MDD (mainly video cards).

the mini is stuck with a Radeon 9200 (32mb or 64mb vram) which kills its small performance gain it had with the slightly faster system bus and DDR. but the QS 2002 model and up G4's can use HDD's larger then 128gb in size. the mini and MDD had bluetooth capabilities, which can be added to any Mac with USB ports.

 
Ok I will have to get my head around all of this jargon. My boyfriends father said that he uses some sort of adapter when he uses his g4 with a newer monitor. Does that sound familiar to anybody?

 
all G4's (besides the mini G4 and iMac G4 and laptops) are called PowerMac G4
what i was asking was, is it a Yikes G4, Sawtooth G4, Gigabit ethernet G4, Digital Audio G4, Quicksilver G4, Mirror Drive Door G4.

i am thinking that its either a gigabit ethernet G4 or a Digital Audio G4 466 or 533. since those models could be configured with a rage 128 pro that had the VGA and ADC on it.

so the reason you say it wont work on your Mac is cause it has a rage 128 pro in it, its a rather simple thing to fix ( if you have the money) is to look for a official Apple shipped Nvidia Geforce2 MX, Geforce4 MX, Geforce4 Ti that has ADC on it, or a ATI Radeon 7500 (or above, sorry cant remember the models that had a ADC port on them).

the flashed PC to Mac of the above models of video cards (that has DVI) will be of no use unless you get a DVI to ADC adapter (but that depends if the DVI output works on the flashed card).

if its a Gigabit ethernet G4 it will only have a AGP 2x slot which will limit you in the video cards you can use ( can only use up to the Geforce 6200, and a ATI Radeon 9800 Pro). if its a Digital Audio G4 it will use up to a Geforce 7800 GS (or GTX or GT) and a Radeon 9800 Pro (and maybe higher)

but that depends if you want to buy a video card for it ( you will have to know what model of G4 it is). or sell the monitor and find the 15" model.

if i remember correctly there was someone selling a few Apple shipped video cards that could drive that monitor on the trading post here. i am not sure if he still has them or not. you will have to PM macsane and ask him if he has a AGP Nvidia Geforce2 MX, or a AGP card with 32mb vram that has VGA and ADC on it. i have bought a few things from him and he is a good friend, and a person of his word. it will just depend on if your located in the USA or not.
thanks for all your help. After speaking to someone in a mac centre it totally makes sense. We have decided to find a new (well old) monitor and not bother with fitting a new video card (we don't want to risk breaking anything).

 
yep, it uses the standard vga connector, it will work on just about any Mac with that connector. the ones you got to watch out about really is the ADC and DVI monitors (more so the ADC then the dvi)

 
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