Mac OS 9 Lives

Classic Mac OS Hardware => General Hardware Discussions => Topic started by: mikkmuzik on July 27, 2019, 05:55:44 AM

Title: 1.25dp fan speed then sleep mode
Post by: mikkmuzik on July 27, 2019, 05:55:44 AM
Hi All
I'm looking for the definitive answer to the fan that wants to take off ....then it goes into sleep mode then is dead....Is this a PSU problem?

it initially fires up ok then the fan starts to speed up then flat out, a click and the mouse pointer disappears then into sleep mode a few seconds later..then restart it and nothing as such... I've done the reset button...any more ideas???? If its the PSU ill get it rebuilt...Thanks for your help in advance
Title: Re: 1.25dp fan speed then sleep mode
Post by: FdB on July 27, 2019, 08:00:00 AM
Some things...

Have you booted with the door open to determine which fan(s) are ramping up before it then goes into sleep mode?

Have you attempted boot with all extensions off?

Will it not reboot, after going through this sequence that you’ve described… unless it’s allowed to sit for some extended period of time?

Apple keyboard and mouse? Any new software recently loaded? Any new peripheral‏s added? Any recent changes / additions made to this machine?

Unplug from power, press start button and hold for several seconds… then plug it back into power and then attempt boot. If this “works” and it still goes through the same sequence then I would suspect a “tired” PSU that needs attention.

When you say a “click” - is that something you hear from inside the machine as it’s ramping up… or a “click” of the mouse button? (If the latter, does it go into sleep mode w/o clicking the mouse?)

Before having PSU rebuilt, I’d pinpoint which fan(s) and probably blow out all dust in the machine and the PSU with compressed air (holding all fans, so as not to overspeed-spin them).

And then... try, try again. ;)
Title: Re: 1.25dp fan speed then sleep mode
Post by: refinery on July 27, 2019, 10:27:10 AM
I'd check that the heatsink is properly applied with adequate thermal grease. What you're describing sounds like the machine shutting itself off due to overheating, the fans spinning up right before it happens is a big clue
Title: Re: 1.25dp fan speed then sleep mode
Post by: mikkmuzik on August 27, 2019, 02:48:50 PM
I have put the paste on the chips..The old stuff looked very sparse and dry....it worked...BUT then i tried putting os9.22 recover disk on it worked for a while (3 hours) ..and now the disk has died...and the unit fan spins again....well to be expected I suppose..So a new HD is in order...BUT the main thing is its usable again, so thanks for the advice BTW the click was from the hd just before it went into sleep mode.
Title: Re: 1.25dp fan speed then sleep mode
Post by: coachla on August 27, 2019, 09:39:16 PM
Disconnect the fans from the mobo. This is a bad design and also generates RF into the audio system which renders it unusable. Run the fans directly off the PSU. At some point you will get tired of troubleshooting this.
Title: Re: 1.25dp fan speed then sleep mode
Post by: mikkmuzik on August 28, 2019, 08:23:25 AM
Its a bit further down the road now...The fan has stopped going mental...120gb hd with 9.2 and osx installed, 1.5 gb ram, I did have a dodgy stick..But it still goes to sleep for no reason, there is no pattern to it..It just goes even if i am using it and also with the extensions off...SO....the PSU? I am lucky as this has always been my back up...yeah right a great backup unit..... :-\
Title: Re: 1.25dp fan speed then sleep mode
Post by: FdB on August 28, 2019, 09:04:35 AM
Seems very familiar… but I can’t remember when I had the similar problem. I didn’t need replace my PSU but I did figure it out eventually. Sorry, my memory fails me.

It’s not an Energy Saver setting or something else in your prefs?

And it is SLEEP, not a complete power off - dead shut down?

ALL connections tight? Wiggle-jiggle wiring and inspect for wiring abrasions and loose connections… especially as they cross the hinge threshold. Sounds like a possible momentary wiring/connection fault or maybe heat related too.

Board screwed tight to chassis? Plug tight into PSU back? Take it down to only one RAM chip, clean and blow out well… and test.

If nothing above seems to be the problem solution, you could then remove PSU plug from MOBO and jumper that plug* to test the PSU. If the PSU and its’ fans continue to run without fail for extended period without “taking a nap”… the it’s not the PSU (of course). Still don't think it's your PSU.

*Hope something above helps before I need to remember which wires need be jumpered on that PSU plug.  ::)

Best of luck & happy hunting.
Title: Re: 1.25dp fan speed then sleep mode
Post by: mikkmuzik on September 11, 2019, 04:52:10 AM
I decided to take the main out and resolder the joints on the power in and ide's...nope....Ok now take the PSU apart and what did i find...a dry joint on the power in cable from the IEC socket on the board..resoldered..and now seems ok....ha ha at the moment......
Title: Re: 1.25dp fan speed then sleep mode
Post by: FdB on September 11, 2019, 08:45:47 AM
CONGRATS!