[comp.sys.ibm.pc] Is it a 6Mhz or 10Mhz AT?

umsmigie@ccu.umanitoba.ca (Jason Smigiel) (06/13/90)

	I have a a cheap 286 AT clone... I've run this "Landmark CPU Speed
Test: Speed v1.05"  program on it and it reports that the machine is
performing like an IBM AT running at 6 Mhz.

	But, I've been told that the machine is most likely a 10MHz.
that is switchable by a jumper on the motherboard.  I've searched the 
board and tried unlabled jumpers at random trying to get the Thing to 
do 10Mhz.  So..... is there a way to determine if the beast will push
10Mhz?

(I have also tried the "Ctrl Alt +" key sequence, but it didn't excite
anything)

I've got Pheonix 80286 BIOS 2.00 if that can help any.

Thanks A Lot,
Jason (The guy who don't know nuthin 'bout IBM's) Smigiel

sonny@charybdis.harris-atd.com (Bob Davis) (06/14/90)

In article <1990Jun13.073623.26400@ccu.umanitoba.ca> umsmigie@ccu.umanitoba.ca (Jason Smigiel) writes:
>
>	I have a a cheap 286 AT clone... I've run this "Landmark CPU Speed
>Test: Speed v1.05"  program on it and it reports that the machine is
>performing like an IBM AT running at 6 Mhz.
>
>	But, I've been told that the machine is most likely a 10MHz.
>that is switchable by a jumper on the motherboard.  I've searched the 
>board and tried unlabled jumpers at random trying to get the Thing to 
>do 10Mhz.  So..... is there a way to determine if the beast will push
>10Mhz?
>

	One way is to look on the motherboard for a crystal
near the CPU. It will be labelled with a frequency that is
TWICE your highest rate. I THINK this is rather universally
true for AT's since the 80286 has internal divide-by-two
on the clock. My 12 MHz AT clone has a 24 MHz crystal that is
easy to spot very close to the 80286.

	Good luck.




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ron@woan.austin.ibm.com (Ronald S. Woan) (06/14/90)

In article <1990Jun13.073623.26400@ccu.umanitoba.ca>,
umsmigie@ccu.umanitoba.ca (Jason Smigiel) writes:
Jason> 	But, I've been told that the machine is most likely a 10MHz.
Jason> that is switchable by a jumper on the motherboard.  I've
Jason> searched the board and tried unlabled jumpers at random trying
Jason> to get the Thing to do 10Mhz.  So..... is there a way to
Jason> determine if the beast will push 10Mhz?

The easiest way to tell is to check all the clock crystals on the
motherboard for one labeled 20MHz (I think most clones still divide by
2?)... If you can only find a 12MHz crystal, then you probably can't
switch it.
						Ron

+-----All Views Expressed Are My Own And Are Not Necessarily Shared By------+
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+ Ronald S. Woan  (IBM VNET)WOAN AT AUSTIN, (AUSTIN)ron@woan.austin.ibm.com +
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