IBM 600E error 192 Hex editor disable?

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ChrisL
BIOS Newbie
Posts: 19
Joined: Mon Dec 19, 2005 1:36 am

Hey everyone,

I was reading through the 600E update thread and saw that it is possible to disable both the L2 cache on the processor and the on board memory. I was wondering if anyone knew how to disable the onboard fan so that it doesn't produce a 192 error on boot.

The reason I want to do this is because I have a 750Mhz mmc-2 running at 810Mhz so I wanted to make the fan run all the time at high rpm so I wired a manual control in that is adjustable to 12v (full speed). The system works very well and keeps the temp around 75* at full load but on boot the machine produces an annoying 192 error every time.
Sharedoc
Notebook Genius
Posts: 679
Joined: Mon Aug 18, 2003 8:46 pm
Location: Finland

Hmm, you could solve the problem by connecting the fan power supply via a transistor or relays switch.
ChrisL
BIOS Newbie
Posts: 19
Joined: Mon Dec 19, 2005 1:36 am

Hey sharedoc,

Here is what I have been working on.
Image
Image

Its a modified Compaq evo 610c heatsink and it fits perfectly after a few modifications.

I am just about done with the project, all I have yet to do are anchor the mounting pad to the processor plate, build a box for the fan from styrene, and figure out the wiring.

I was hoping that you could help me with the 192 fan error. I was planning to wire the new fan to the USB 5 volt contact and use a diode and 1000 ohm pot to vary the voltage manually. Problem is I have no idea how to deal with the 192 boot error.
beatoem
Chip off the ol' block
Posts: 120
Joined: Sun Jan 16, 2005 11:38 am
Location: sydney,australia

nice fit ,maybe you can cut the portion of the original fan and shroud and mount so air can blow through that beaut radiator,even if not affixed to cpu the airflow will help,that is if the the fan cuts in at all ,irrespective 8
the fan error will be a thing of the past.

**i found holding the escape button in power on helps rid of 108 error post more times than not,conversely i am pondering experimenting with different value resistor to see if that helps rid the 108 message,at this stage with no holding keys i get it around 2/4 and 1/4 holding escape key on power up.
d saint"
ChrisL
BIOS Newbie
Posts: 19
Joined: Mon Dec 19, 2005 1:36 am

yea I thought about doing that and that was my plan but the problem is that I can not think of a reasonable way of cutting the fan housing. Any debris will enter the fan unit and obstruct motion. It is not possible in my opinion to remove the fan without breaking it because it is built into the aluminum housing.
My best shot to solve this problem is to find the byte in the CMOS that controls the fan power-on test at POST and set it to off. I have no clue about hex language or programing however.

I am going to do a tutorial on how the modification can be done because I learned many short-cuts now that the most important piece is fitted and installed.

All you need is a dremel tool with a cut-off wheel and a small razor-saw to cut the plastic on the 600E casing. I hope that I don't have to buy a new fan with a speed output wire becuase the one that came with the heatsink flows ALOT of air
Sharedoc
Notebook Genius
Posts: 679
Joined: Mon Aug 18, 2003 8:46 pm
Location: Finland

The fan error 192 comes from the bios checking the fan sensor input both when the fan is on and off in the beginning of boot.

I noticed that the fan is driven with different voltage levels ranging from 0 to 5 volts, maybe even more.

So an easy way to drive the fan would be switch like this


+5 from USB
|
X fan
|
|/
fan ctrl ---| 1k |------| power transistor (NPN)
|\
V
|
_ GND


Please let me know if it works.

Sorry, that the figure distorts because spaces are compressed. Anyway there is a power transistor, whose base is driven via 1kohm resistor.
ChrisL
BIOS Newbie
Posts: 19
Joined: Mon Dec 19, 2005 1:36 am

Thanks for the suggestion. I am not understanding your figure though. Am I using the fan senser input on the moterboard for the gate of the transitor?

So +5 comes from USB and I am using the fan sensor and the ground from the fan plug?
Sharedoc
Notebook Genius
Posts: 679
Joined: Mon Aug 18, 2003 8:46 pm
Location: Finland

Connect +5 volts to the + end of the fan. Connect - end of the fan to the transistor collector. Connect fan control (right wire) via 1kohm to transistor base. Connect emitter to ground. Keep fan sensor (middle) wire as it is
ChrisL
BIOS Newbie
Posts: 19
Joined: Mon Dec 19, 2005 1:36 am

Ok I'll give that a try, I will report my results soon
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