917Mhz from 1.25Mhz DUAL left. Is my G4 dead?

[paule]

Since 20 years my G4 Dual MDD (1.25Ghz) is running for music composing (Protools Mix 3) without any major problems on OS9.
But since two days I am fighting:
Symptoms. random freezing while or shortly after booting! and all of a sudden: CPU power lost!!! 917Mhz left!!!!!!
Already checked in a naked G4: software (system extensions) and hardware checked (RAM, Harddisks, USB Hubs).

I disconnected everything from the G4 and just started step by step. All of a sudden the system profiler tells me that my G4 Dual 1.25 has only 917Mhz left.

Can anyone imagine what could be the reason for that? Could this drop of CPU power and randomly freezes caused by a faulty Power Supply?

Thanks for any help,
paule.

[smilesdavis]

yes reapply cooling paste. clean. reapply.

[paule]

Hi,
thanks smilesdavis for the hint. I have ordered cooling paste. Let's see if it helps.
By the way: I found one culprit, which I have forgotten to disconnect: one of my dvd-superdrives causes the hangs when starting up, because its jumper aren't set to "cable select".
I have tested for hours now, but too many restarts also damaged at the end my startup disk. :-(
I am glad that I had a backup! :-) But at the moment the G4 is running better (but not perfect), but too crazy is, that the CPU is still only running on 917Mhz ... the same CPU rate you get when you start the G4 in "safe mode". But I am not in "safe mode" anymore and I don't know how to get out of it to get full speed 1.25GHz back. PMU reset and PRAM didn't help.

Best and thanks for any help,
paule.

[GaryN]

the CPU is still only running on 917Mhz ... the same CPU rate you get when you start the G4 in "safe mode". But I am not in "safe mode" anymore and I don't know how to get out of it to get full speed 1.25GHz back. PMU reset and PRAM didn't help.

I'll ask DieHard to confirm this, but I have never heard of the CPU(s) throttling down slower in Safe Startup Mode. AFAIK, Safe Mode disables certain Login Items, Extensions, dumps Font clutter and generally skips over everything not absolutely essential at Startup to prevent any of those from hanging up the process. Also, it's only applicable to OSX – the rough equivalent in OS9 is hold the Shift key for "Extensions OFF".

I'll make an educated guess here and suggest that maybe one (or more?) of the clockspeed-setting surface-mount resistors on the CPU daughterboard has come loose… possibly from the CPUs running hot for a looong time. I'm (again) guessing that after 20 years (!) without thermal paste renewal and (possibly) other deferred internal dust-out maintenance you have slowly cooked the daughterboard into… crispy-ness?

** Note: You didn't swap out the main fan at some point for something quieter and connect it to the same place as the original, did you? That is a certain way to cause the procs to run hot – ALL of the time.
Part of the problem is that there is simply no good temperature monitor for OS9 as in OSX. The only one that can possibly work is in "Jeremy's Bundle"… a set of Control Strip Modules, one of which is a temp gauge. I'll note that it does NOT work on my MDD with a Sonnet hot rod CPU card and I honestly cannot remember if it did with the original CPUs. I think it did, but…

Again referring this to our resident computer hardware know-it-all genius DieHard, does this sound like a decent theory? The obvious test procedure is a CPU swap - I know, big help if you don't have another on hand - OR is there some/any other likely suspect?

[DieHard]

I'll make an educated guess here and suggest that maybe one (or more?) of the clockspeed-setting surface-mount resistors on the CPU daughterboard has come loose… possibly from the CPUs running hot for a looong time. I'm (again) guessing that after 20 years (!) without thermal paste renewal and (possibly) other deferred internal dust-out maintenance you have slowly cooked the daughterboard into… crispy-ness?

Yeah, I was leaning toward a CPU daughter board issue also.

If it was a logic board system bus speed issue, (like going form 167 to 133); the quick math would be:
1250 Mhz. (1.25 Ghz.) / 167 (bus speed) = 7.485 Multiplier
So... if it went to 133 Mhz... 133 X 7.485 = 995.5 Mhz, NOT the 917 reported, so my dear Watson the issue is in the CPU daughter-board

The 917Mhz. is a result of the following math (PLL Multiplier):
5.5 Multiplier X 166.66 (Bus) = 917 !

The stock setting for your 1.25 Ghz. should be (PLL Multiplier):
7.5 Multiplier X 166.66 (Bus) = 1249.95

See the Table here: (Posted by PT5)
http://macos9lives.com/smforum/index.php/topic,1652.0.html

This is Literally a single resister, PLL_CFG[0] that is now Open

0=Closed, 1 = Open

1250 Mhz (1.25 Ghz Stock)
PLL_EXT = 0 (resistor or bridged)
PLL_CFG[0] = 0 (resistor or bridged)
PLL_CFG[1] = 0 (resistor or bridged)
PLL_CFG[2] = 0 (resistor or bridged)
PLL_CFG[3] = 1 (no resistor or open)

917 Mhz (Special Setting)
PLL_EXT = 0 (resistor or bridged)
PLL_CFG[0] = 1 (resistor or bridged)
PLL_CFG[1] = 0 (resistor or bridged)
PLL_CFG[2] = 0 (resistor or bridged)
PLL_CFG[3] = 1 (no resistor or open)
 
Lastly, download and burn the MDD digs from our download section, and run extended tests

[paule]

Hi GaryN and DieHard,
thanks for this incredible expertise on my problem. You are my heroes! I could barely follow DieHards calculation, but I am afraid he is right. I have changed the thermal paste one time when I have built-in my verax-fan-kit ... 20 years ago. But I am sure that the verax kit is doing a fantastic job and this shouldn't be the reason for a fried CPU. But that's 20 years ago and since that I was afraid to "redo" the thermal paste again, because I have read so many article about damaging the G4s CPU-board in this process. The temperature always were around 40 degrees Celsius (because the machine was running with the verax kit and an opened MDD (really open for better cooling!!).
Okay, what are my possibilites: I cannot renew any solder joints ... I could swap the board from my second "SOS"-G4 MDD 1Ghz. Mmh, but this one is running at the moment and I have just swap the harddisks to the newer (a little bit slower) G4 with only 1Ghz. I will see if this SOS-G4 is running with its 1GHz almost as fast as the 1.25GHz or I have to buy a new one somewhere. I was glad to have to 1Ghz waiting for that case, but there is no verax-kit in it. Maybe I get another with the verax-kit or a have to swap the verax-kit including the fans and PSU from the fried G4 to the slower one. But I am glad that I could (maybe) still use the verax-kit. Another G4 is findable - I hope.And if I find something I should renew the thermal paste for sure ...

Thanks a lot my friends,
paule.

PS: Should I keep the fried G4 because of its parts? ... if GaryN and DieHard is right, the culprit would only be the little CPU board.... mmh, maybe I can get a little CPU-board too, swap it and all of a sudden I have repaired G4 1.25 again!! :-)

[DieHard]

verax kit...

Yes, the famed Verax Kit... so rare... so elusive... that many don't know what we are talking about... To find one of these today would be extremely rare indeed.

For member interest, you can see this extinct exotic animal in this video

[youtube]jEiMHOyMOc8 [/youtube]

[IIO]

www-ebay.de//special_offer/dual917MHz_Powermac-[Ultrarare]/kaufmich.html

[IIO]

i have one verax fan left, but the blue one, and i always thought it seems to be not cooler and not less noisy than the original fans.

[GaryN]

Hi GaryN and DieHard,
thanks for this incredible expertise on my problem. You are my heroes! I could barely follow DieHards calculation, but I am afraid he is right.

Yeah… math geeks…

I have changed the thermal paste one time when I have built-in my verax-fan-kit ... 20 years ago. But I am sure that the verax kit is doing a fantastic job and this shouldn't be the reason for a fried CPU.

OK. Know that you're one of the few lucky ones who actually have that fan kit. It's the only MDD-specific fan upgrade ever made that both more or less works and is also quieter than the stock Pabst by far without sacrificing cooling for the sake of quietness.

But that's 20 years ago and since that I was afraid to "redo" the thermal paste again, because I have read so many article about damaging the G4s CPU-board in this process.

Phoo ! You did it once, and evidently did it properly and now you're a veteran. Why should the second time be any different? Piece 'o cake! Seriously, You can and should renew the paste after so many years on a vintage machine you depend on. Actually, you don't have a choice because one way or another, that board is coming out for service or replacement. Think of it like a lube and oil change on a car… you wouldn't skip that just because you're afraid of a little dirt only to have the engine seize on the highway… late at night… with your girl in the passenger seat…

The temperature always were around 40 degrees Celsius (because the machine was running with the verax kit and an opened MDD (really open for better cooling!!).

Wow… The Verax kit is the only kit that does NOT cause a problem running the MDD open. It must be louder open than closed however (?)
So now I wonder: When did you first notice it is running at 917 MHz? Running at 3/4 speed will certainly keep it cooler that a fan upgrade… 40°C is freakishly low for an MDD. How do you know the temp, by the way? Is that in OSX? If it's with a temp probe pointed at the heat sink, that doesn't count. That doesn't measure the temp at or very near the CPUs.

Okay, what are my possibilites: I cannot renew any solder joints ... I could swap the board from my second "SOS"-G4 MDD 1Ghz. Mmh, but this one is running at the moment and I have just swap the harddisks to the newer (a little bit slower) G4 with only 1Ghz. I will see if this SOS-G4 is running with its 1GHz almost as fast as the 1.25GHz or I have to buy a new one somewhere. I was glad to have to 1Ghz waiting for that case, but there is no verax-kit in it. Maybe I get another with the verax-kit or a have to swap the verax-kit including the fans and PSU from the fried G4 to the slower one. But I am glad that I could (maybe) still use the verax-kit. Another G4 is findable - I hope.And if I find something I should renew the thermal paste for sure ...

Of course you can! According to DieHard's chart, there is only one little SMD that has come loose and the chart even points right to the correct one: R403
By "come loose", I mean the solder on one end has developed a minuscule crack. A quick heating with a very small-tipped soldering iron will melt it back together in a few seconds. In fact, the resistance is negligible and unimportant. If you break it loose and lose it in the carpet, you can just bridge the contacts back together with a tiny bit of bare copper wire soldered down to the pads. If the worst happens and you drop the whole board on the floor then step on it in a panic, then you can consider replacing it but until then, it's a simple fix.
Compare this with the other alternatives you describe… moving half the guts from one machine to another and hoping everything just starts up without a glitch afterward. The logical course is clear. If the worst somehow happens, I'm sure either DieHard, myself or one of the other intrepid souls around here can scrape up a working 2x1.25 for you. Go for it!

When you own a 1966 Mustang, you really need to not be afraid of using a socket wrench every now and then.

[paule]

Hi all,
thanks a lot for encouraging me to fix it by myself. This will be an adventure - I am a little bit excited now.
I have attached two pictures and I am not sure, if these (R403? or R8) are the culprits. They look pretty normal and I am afraid to touch them with the hot solder. Do you really mean the R403 (or R8) needs to be fixed? In my eyes it looks pretty normal. Can you give a hint on which one I should work on?

Thanks,
paule.

PS: About the heat I am not sure about the 40 degrees C. I think while running it will really hit the 56 degrees at the end. I have only used the "Temperature Monitor" in OS X in the beginning of restart nightmare and in the first minutes it was around 40 and less more. But I had no time to observe this any further because of the freezes all the time. But I remember I made a lot of test years ago with the G4 closed and opened and the temperature (of the unreliable) "Temperature Monitor" told me to leave it open.

[FBz]

Nice big pics Paule.
(Might want to resize any future pics.)



Processors don’t appear too baked - but nice to see w/o old paste on them.
Both appear same color and no evident appearance of too much heat / damage.
But that paste does look very well cooked.

Clean ‘em up and repaste. Blow off all accumulated dust.
Reinstall and test.



If you must test the resistors, simple continuity should be sufficient.
And for that I use the makeshift sewing needles attached to probes.
(Those resistors & solder points are so tiny.)

There’s a very good chance that the old paste allows the machine to heat up
so quickly that it just freezes the machine. New paste is easy enough to do.
(It’s the old paste thorough cleaning that’s a real pain.)

If you determine that you need another daughtercard, I’m almost certain that
I have some dual 1.25’s and a few single 1.25’s. PM me your address and one
can be sent your way as necessary.

BTW… 56˚C isn’t so bad for operating temp.
I don’t get nervous until I get above 140˚ F. (60˚C)
And at that higher temp - I auto repaste.

Wouldn’t hurt to remove and reseat the daughtercard either.
(Those many contacts need reseating after such a long time running.)

Good luck.

[paule]

Hi also FBz and all the other helpful people here,
thanks for the hints. I have one more question: there is a little plastic cover (rectangle) on the CPUs and as soon as I have start cleaning the thermal paste, the paste is running UNDER the plastic cards. Do I have to remove these plastic cards and clean the whole area, because it seems to me that they are hard to remove and even harder to get it one somehow?!?!?! Maybe the plastic cover are not really needed here?
Is this thermal paste a problem for the contacts near to the CPUs and I can keep the plastic there like it is after my cleaning?

Thanks in advance,
paule.

[FBz]

Rain day here so no outside fun today.

I have removed the clear plastic before with no apparent negative after effects - but I like to leave it on.

Normally, I’ll use a toothpick or a small bent end of a paper clip (or smaller copper wire) to carefully reach in and under the plastic to remove the old baked in / and on paste. (Only under the plastic / not touching the shiny metal surface.) AND this all after a good saturation and wipes with 91% isopropyl alcohol cotton swab to loosen it all up. (Daughtercard removed from the machine.)

A little lightly sprayed canned air, under the plastic film doesn’t hurt either... afterwards.

P.S. Thanks for the new pic. Looks like someone REALLY applied a lot of paste previously to get so much under that plastic.

[DieHard]

I have one more question: there is a little plastic cover (rectangle) on the CPUs and as soon as I have start cleaning the thermal paste, the paste is running UNDER the plastic cards

No, just leave it, this always happens, paste is non-conductive and old paste will just live there for the rest of it's life, just make sure to clean the CPU Die.  If you don't have the "pro" cleaning stuff; use dollar store Goo gone and then clean off goo gone with alcohol.  It's always a 2 step process.

1) Clean the metal with goo gone (or arctic silver remover)
2) clean the oily residue off with alcohol (arctic silver metal purifier)

Obviously, do the heat sink in the same manner.

Then apply a thin line of paste (thickness of a green inch worm) in the center of each CPU rectangle traveling the the long length as it will spread out on it's own when you attach heat sink

It's hard to believe I cannot find a good video or pic of the proper amount and placement.

This guy put 4X what is needed, however if you look at just half of the straight line portion in the center and ignore the rest that is what you want
[youtube]2ERBCYFcVPQ[/youtube]

[FBz]

Two times what is needed? Yikes!!!

My gawd man, I use one little blob a little over an an eighth of an inch in total diameter and spread that around with a toothpick until it appears fairly even across the entire surface.
Then after positioning the heatsink, I'll slightly turn the heatsink a bit back and forth (slightly) to get smooth even coverage. YMMV

Haven't baked one yet. (Fingers crossed.) 

[DieHard]

Two times what is needed? Yikes!!!

My gawd man, I use one little blob a little over an an eighth of an inch in total diameter and spread that around with a toothpick until it appears fairly even across the entire surface.
Then after positioning the heatsink, I'll slightly turn the heatsink a bit back and forth (slightly) to get smooth even coverage. YMMV

Haven't baked one yet. (Fingers crossed.) 

Yeah, this guy is a hack, I included the video as what NOT TO DO, because I could not find a good picture or video...

So for clarification... a thin line in center, start about 1/4" from top edge, thickness of a round toothpick (thanks FBz), and stop about 1/4 inch from bottom edge, NO spreading (leaves air pockets unless you are a pro like FBz); it will spread perfectly on it's own

[paule]

Hi all,

O.K. thermal paste was delivered yesterday. I have renewed the thermal paste.

Conclusion:
1.) The first 10 attempts to boot the machine was accompanied by several freezes while and after booting still the same. (Booting with or also with the G4 System CDs causes freezes!!) Strange is that I get after a freeze and a hard reset all the time a black screen after rebooting and I have to reboot with a hardreset a second time to get the machine somehow to life again.
2.) Multiple times I have tried to access the system profiler and after all these freezes it showed again 917Mhz. :-(
3. ) Totally frustrated I thought maybe it helps to install a fresh system on the boot drive. (10.2). All of a sudden the system profiler showed my 1.25Mhz speed. I don't know why. :-)
4.) Reinstalled on the same harddisk (via SuperDuper) the formerly working 10.3.9 image which runs without any problem in my SOS-G4-MDD-1Ghz-Machine. After that again freezes in the same manner and again 917Mhz!!! :-((
5.) Last try about a faulty ram, because since that time I have used only one 512MB and I tried 6 of them in different spots and also at the end I used the 4 well combined RAMs which run in the SOS-G4 without a prob ... but .... still getting freezes and now I am back on 917Mhz. :-((

I don't know what to do. Maybe the motherboard or whatever little piece is the prob. I think II am done with this G4 1.25. So I will remove the Veraxkit and the associated PSU and MAYBE will put in the 1Ghz machine or MAYBE I will see if I can get another 1.25 on ebay and put it in there....
I am no technician and I am not able to find out which chip or ELKO or solder is the culprit. I tried my best and thanks for all the help from you.

Thanks a lot, but I think it is "time to say goodbye" to this machine.

paule.

[DieHard]

1.) The first 10 attempts to boot the machine was accompanied by several freezes while and after booting still the same. (Booting with or also with the G4 System CDs causes freezes!!) Strange is that I get after a freeze and a hard reset all the time a black screen after rebooting and I have to reboot with a hardreset a second time to get the machine somehow to life again.
2.) Multiple times I have tried to access the system profiler and after all these freezes it showed again 917Mhz. :-(

NOT strange at all, you are running a Mac with a hardware issue and mac hardware issues can easily make you think you are going nuts; for some reason I thought we were on the same page. Ok, I'm not sure how to explain this any clearer, if someone dies of heat stoke (or some other underlying issue) giving them a cold glass of water is not going to revive them.  We clearly explained the daughter board (CPU board) is not behaving to specifications.  So no amount of Arctic Silver is going to fix that.  Keeping the CPU cooler will not correct the obvious hardware issue of the 917 clocking. The CPU board is most likely the ONLY thing that needs swapping out (it may have additional issues, like blown cache) since you mentioned the "slowness".

3. ) Totally frustrated I thought maybe it helps to install a fresh system on the boot drive. (10.2). All of a sudden the system profiler showed my 1.25Mhz speed. I don't know why. :-)
4.) Reinstalled on the same harddisk (via SuperDuper) the formerly working 10.3.9 image which runs without any problem in my SOS-G4-MDD-1Ghz-Machine. After that again freezes in the same manner and again 917Mhz!!! :-((

Obviously, inconsistent flaky results, again very clearly pointing to an INTERMITTENT CPU board issue.  Very easy to swap it out. If for some insane reason a replacement CPU board does not clock correctly, then it's logic board time.

5.) Last try about a faulty ram, because since that time I have used only one 512MB and I tried 6 of them in different spots and also at the end I used the 4 well combined RAMs which run in the SOS-G4 without a prob ... but .... still getting freezes and now I am back on 917Mhz. :-((

OK... so let's stay focused before you create an additional issue(s).  The RAM will not effect the wrong CPU multiplier. So concentrate solely on the CPU board for now

I don't know what to do. Maybe the motherboard or whatever little piece is the prob. I think II am done with this G4 1.25. So I will remove the Veraxkit and the associated PSU and MAYBE will put in the 1Ghz machine or MAYBE I will see if I can get another 1.25 on ebay and put it in there....

If you can silver it, you can surely replace the CPU board, no soldering needed, just a few phillips screws, no need to take out the mother board, fuck with the PSU/Power supply, or swap the machine yet.

Thanks a lot, but I think it is "time to say goodbye" to this machine.

OMG... the rest of the machine is probably 100%. steps for now...
1) Replace the CPU board
2) Arctic Silver the replacement
3) with the storage (Hard drive/SSD) unplugged, boot from the CD with the diagnostics and run the extended tests.  plug the mouse into your mac keyboard as the diagnostics like to see it there and you may not have a mouse cursor if you plug the mouse into the tower. Get the diagnostics here: http://macos9lives.com/smforum/index.php/topic,822.0.html
4) after a clean bill of health, go nuts with software

[paule]

Hi DieHard,
this is the best forumboard I have ever been with so nice people!
Okay, I have sent FBz a private message to get this thing going. Thanks a lot - I will swap the CPU and let's see if I can get this machine running again (with your help!).

Thanks in advance,
paule.