Info-Mac

Hi All

I have a dual processor G5 (June 2004 model) that will not boot unless I heat the MB in the area of the Ram slots with a hair dryer for about a minute, then it boots and runs fine. Cold starts give the 3 flashes of the power button light, indicating a Ram problem. I've tried all slots in different combinations, different ram sticks, cleaning the contacts with the pencil eraser trick. Nothing else works.

It's been suggested that I try baking the MB at low heat in the oven to maybe fix a micro crack in a solder joint. However, I'm told that after reinstalling the MB I need to calibrate the fans or they will run at full speed. I can't seem to find the calibration software anywhere, so the question is, can anyone confirm that recalibration would be necessary and where I might find the software.

Thanks.

mac2geezer wrote:I have a dual processor G5 (June 2004 model) that will not boot unless I heat the MB in the area of the Ram slots with a hair dryer for about a minute...It's been suggested that I try baking the MB at low heat in the oven to maybe fix a micro crack in a solder joint.

If you're going to try baking motherboards in ovens, dare I suggest you write-off this G5 as kaput. I've never heard of such a thing and that doesn't sound like an ideal solution at all.

I second the opinion that baking a motherboard is half-baked at best. Subjecting it to a temperature hot enough to reflow solder will destroy the ICs. Unless you have been removing and replacing the RAM chips several times a day for the last 6 years, it is very unlikely that a defective solder joint would now appear.

What is more likely is accumulated oxidation has formed on one or more of the interconnections. On RAM chips, you can try using a clean rubber eraser, such as on a typical mechanical pencil, to polish the contacts. Standard caveats concerning static electricity discharge and excessive heat from friction apply. There are low-powered vacuum cleaners with anti-static nozzles available for cleaning sockets, or you can try compressed air. If you use "canned" air, be sure that it contains no petroleum-based lubricants, as these will congeal over time and form an electrically resistive plaque on the connections.

The thermostat in a computer case has no user serviceable parts. The only way you can recalibrate is in software. You would need to identify and edit the appropriate plist or hack the OS. O_o

Well, I don't really plan to bake the MB even though there are numerous posts on the web from people who have successfully done it. I disassembled the G5 yesterday and inspected the back of the MB with a magnifying glass and saw nothing that appeared wrong. I've twice cleaned the Ram contacts with an eraser and have used canned air on the MB, all to no effect. One more possible attempt would be to try cleaning the Ram slots with something; isopropyl alcohol maybe? The fact that i've tried all the slots with no change suggests that's not the problem anyway.

Hi, technically speaking if you experience problems which are rectified by the application of heat, it indicates one of two things.

You either have component failure.
Or you have a base failure in terms of routing and contactors.

But as computers are so complex, and as Apple and PPC are so reliable, I would tend to explore elsewhere.

If your G5 is failing to boot, this may be for several reasons.

The boot sequence of a G5 and macs in general require the presence of a trickle current, this current stems from the battery, or from the power rails. The application of heat tends to alter electronic thresholds, therefore your computer is becoming more efficient, as it gets hotter, thus boot signal reaches its threshold.

If your battery has got flat, it is quite probable that you have memory corruption, this can be restored by doing whats called a cuda reset. There are two aspects to pram pram and nvram. If Pram reset does not effect change, nvram reset will.

Cuda reset is another way of ensuring that your computer NVRAM is restored to factory origins. You wil lose prem settings, and your computer won't know where the disk drive is, so you have to boot holding down the keys for the cdrom or net boot, you know the stuff.

Before doing this by all means check your memory cards. Clean with a dry leather cloth, any of the contacts you have spoiled to date. DEFINATELY DONT USE GRAPHITE PENCIL ON THE CONTACTS THEY ARE GOLD.

YOU NEED TO ENSURE THE MEMORY CARD DIMS ARE PROPERLY SEATED IN THEIR RECEPTIONS. CHECK THIS, SOMETIMES YOU THINK THEY ARE IN, AND THEY AREN'T.

Remove the battery and replace it with the one recommended by your APPLE service point. IF YOU DONT HAVE ONE THAT CAN RESPOND, RADIO SPARES ELECTROMAIL, ON A CARD. DONT USE A HOBBY SHOP. Any old 3V Duracell battery will NOT DO. You need a lithium thionly chloride 3.67 volt battery, for the mother board.

Has someone put the wrong battery in? Is the battery 3 V not 3.67, it will be written on the battery somewhere. SAFT, SUNASHINE(which is what you want a bit of sunshine in your life), RS, whatever, 3.25 v Duracell camera batteries are no good!

Then you can do the cuda reset.

WHEN YOU BOOT, FINALLY, YOU WILL BOOT FROM YOUR ORIGINAL CD ROMS.

DO A SYSTEM REINSTALL, INSTALL IN PLACE, FROM A KNOWN OEM APPLE OS.

THIS PROCESS WILL GET YOUR MAC INTO ACTION.

I suspect, you panicked, and freaked out a bit, easily done, SUSPECT hardware failure last: is seriously doubt you have one of these.

If you still have no success, after this process, the first point of investigation is to explore the presence of a trickle volt charge to the ic, its about 3v trickle. I can't tell you where to find it because I am not in front of your computer, but looking at the power switch, will reveal some kind of source, your computer sends these 3 volts to enable the boot sequence, first.

Unless you have been a real muppet, it is very doubtful you have a hardware fault.

If your inspection reveals the presence of trickle volts, the next thing is does that get to the psu enable area? This proved, all else explored, then and only then should you even contemplate, inspecting the motherboard, for component failure.

I would definately not put your computer in the oven for a flow solder repair, if you have a hair fracture, how did it occur? If you have to repair at all a hair fracture, repair with cold cure solder paste. Apple do not recommend, any person outside their support network, even touching their hardware, but as you have demonstrated competance with the application of heating, I am making the assumption you are quailified enough to be self serve.

PLEASE DONT FORGET several other factors prevent startup. Read all the significant support from APPLE site, read your manual of advice. Remove keyboard, and mouse and all other peripherals. Only when all these factors are removed can you be sure to explore the case.

Beware the turkey theif! If your are in an office network, these clowns dust the case, keyboard or hardware with radon gas, then tell you you have hardware problems, the computer is shagged and as luck would have it are prepared to give you a swap, of exchange to some other system. Your PPC G5 is one of the most reliable pieces of electronic equipment ever made by mankind, believe me, those things run in nuclear power plants, (cite:RAD750)!

You aint gonna have a hardware problem after reading and following this advice.

See you online soon!

Dr David Christmass

Thanks for the reply. I tried several of the things you recommended; checked the Pram battery for proper type and checked the voltage, removed and cleaned the ram contacts (not with graphite) several times, tried all the ram slots in various combinations, reset the Cuda switch as per Apple instructions. The more things I tried the worse the problem got. Finally, after I could get it to boot with heat it would KP very quickly. Fixed the problem a week ago by installing a new (used) logic board. The G5 runs great now.

Also, before installing the new logic board, I tried running ASD and it would start to run then the G5 would just freeze. That's when I started looking for another logic board.

Hi my only question is what caused the board to fail, in the first place? Make sure the psu is alright, no over voltage, use surge protection or a UPS as apple advise and keep the thing crystal clean. Contact tech support at Apple over getting the old board looked over, I am sure they will want to know how and if they got anything wrong.

Best wishes to you, I am so pleased your back online, I know the United States best kit is Apple PPC and Motorola, I remember them from Henry's radio days!

David