[comp.sys.ibm.pc.hardware] AT clone won't do turbo

mikem@hechcx.mkt.harris.com (Mike McCole) (12/11/90)

 I have a 286 motherboard with the G2 chipset that no longer runs
 at turbo speed (12 Mhz).  The board just will not go into that mode, 
 the turbo light doesn't light and it SI's at 6.7.  

 My turbo switch is ok and I've Ohmed the traces from the turbo switch pins to:
 1-ground and 2-a pin on the keyboard controller chip.  

 I've tried replacing the keyboard chip, to no avail. 
 I don't know how the board goes about switching clock speeds, I suspect
 that it is done by a small relay on the board (at least I've found a small
 relay on the board) but I don't know for sure that it does the deed. 
 
 If you know how this board ( or ANY board ) switches clock speeds, please 
 post a response, any and all pointers appreciated.
  


				     Mike McCole


305-973-5466


 Using the C shell without history is like getting syphillis without sex.