G4 Dual Mirror doors - black screen, no boot sound.

Hi

I just got my hands on a very cheap Power Mac G4 Dual 1.25ghz "mirror door" with 17" cinema display.

There was no harddrive installed because the org. died.

The ram wasen't installed, but I got 4x512mb and 1x1024mb modules.


When I power on the machine, the harddrive I have put in, spins up, but there is no "startup sound" as I read there should be.

The screen is all black with no response at all (I can power on the machine through the powerbutton on the screen)


I have tried to pull out the battery in 10min, and made an PMU reset with no luck.
The battery shows 3.6v when I test it - So it should be ok?


I have tried several different RAM setups, how should I place the RAM in the slots? one in J20 and J21 ?

And where should the system disk be placed? There is several IDE ports where I can put it.
(just so I know these two things are ok)

There is a little red diode lighting right next to the RAM slots, should it be red?


Hope someone can help me, else I will have to sell the machine again (in parts)

What RAM did you get? That machine takes PC2700 DDR SDRAM. There are 4 Dimm slots and each will take a 512Meg PC2700 DDR. If you went with higher specked DDR like say PC3200, that could be an issue depending on the RAM.

There should be one IDE hard drive port free as far as I know. The other is the the DVD/CD Rom drives.

Update: The MDD is the only Powermac I have never got to work with. I got some pics and it looks like there are 2 IDE ports besides the one for the optical drives. Either should work. If there is no hard drive the machine should make the startup sound and light the screen if the RAM is correct.

Ok, there is 4 free IDE on two cabels.

I know from PC's that some motherboards requires that you put the ram in right order.

On my MAC board they are placed in this order:

J20 J22 J21 J23

The 4 512mb ram is not 100% even. but its 2 pair.

Should I mount on pair in J20 and J21 or ?


The ram is PC2700


Thanks

I just found out, that the light on the screen should continue lightning when turning the mac on, it dosen't!

You never verified that you are using the correct ram...are you using 184-pin PC2700 (333 MHz) DDR SDRAM?

Also be aware that PC-2700 ram that is used in "WinTel" computers may not always compatible with a Macintosh. If the ram came out of a Windows computer...it may not work in a Mac.

- Nick

The ram is PC2700 and was used in the mac when it was working.

I have tested the ram with a PC, and they all work.

torbenc said:

Hi

I just got my hands on a very cheap Power Mac G4 Dual 1.25ghz "mirror door" with 17" cinema display.

Click to expand...

Thanks for the info on the ram.

Honestly, without knowing more of the history of this computer...we may be "spinning our wheels" trying to figure out the problem.

You also mentioned that you get no display (screen is black)...the video card could be defective.

You got this G4 desktop "very cheap" for a reason...It Doesn't Work!!!...unless you can verify for us that it was fully operational before you bought it.

- Nick

The seller told me that the harddrive stopped working after he got a macbook, and therefore he diden't buy a new.

I tried to put in a newer ATI agp card, but then it woulden't do anything at all.

I just thought you had some tricks I could try. I haven't worked with mac the last 6-8 years, but bought this to play around with.

torbenc said:

I just thought you had some tricks I could try. I haven't worked with mac the last 6-8 years, but bought this to play around with.

Click to expand...

I'm thinking that if something is REALLY wrong with it...no tricks will help.

I know that you measured the voltage of the PRAM battery...but voltage is not always a good measure of a batteries condition...amperage is better.

For example...a car battery is 12 volts. You can measure it's voltage & get 12 volts...but it still may not start your car, because it's old & has no amps.

The only other thing I can suggest is a new PRAM battery. Some Power Mac's will not start without a good PRAM battery. I had it happen recently on an older G3 Desktop.

- Nick

I ordered a new battery earlyer today, and found a used video card on ebay for $16.

I can spend about $100 to get this on working, and it would still be cheap (after mac prices in my country)

Did you try a PRAM Reset? You said PMU which is Power Management Unit. PRAM is the parameter RAM.

Hold down Command+Option+P+R keys right after you press the power button and keep them down and see if you hear a startup sound. If you do, keep the keys down until you hear at least one more startup sound then let go.

Yes I have tried a PRAM, nothing happens there either. (I makes the same "boot up" sequense)

Got a new battery - that diden't work either.

I found a used working videocard very cheap - I will get it in few days.
If that dosen't work, I can sell it and make a few bucks on it on ebay

Maybe it's the PSU as I can read here: http://www.mac-forums.com/forums/apple-desktops/164007-new-mac-having-powermac-g4-issue.html

Now I measured all the PSU outtakes - All showing the voltage they should (after this schematic Mods to Mirror Drive Door Power Supply)

Still have some unanswered questions:

Right next to the ram sockets, there is a little red light - should it light red normal? (on PC motherboards, red light is normal not good)

When I press the power button, it only lights for a few sec. (The button)
After 10-15 sec. ALL fans in the cabinet starts to run at max (very noisy) Is that normal?

Sounds like you have a dud logic board.

Also when everything spins up (HDD etc.) ?

Got a new videocard - same problem.

I read a thread somewhere, that one had the same problem, and that was the CPU that was dead. (that why the fans start to go nuts.)

A "new" used CPU (dual 1.25) is a $90 payout. But if that dosen't work, I can always sell it with almost no loss.

I now got stubbornly and want to get it to work!

torbenc said:

Got a new videocard - same problem.

Click to expand...

What video card did you get...was it a "genuine" Macintosh video card...or is it a "flashed" PC card?

$16 even for an older used Macintosh video card is pretty darn good (if it works)!

Thanks,

- Nick

It's an "Apple" ATI 16mb PN 109-72700-02 ADC vga AGP. (The info I got from the seller)

The board is though IMO 99% a pure ATI.

Hate to tell you this but on most occasions one buys a machine sans HDD, memory etc, she is a goner and suitable for parts only.