[comp.sys.ibm.pc.hardware] AT Clone Clock Chip - How to Fix?

khan@ux1.cso.uiuc.edu (Scott Coleman) (08/14/90)

I have a '386 AT Clone with a malfunctioning real-time clock chip. 
Specifically, the clock loses time while the power is turned off. I've already
replaced the battery which backs up the CMOS (not sure if that battery also
backs the clock, but thought I'd try it), to no avail. I'd like to avoid
sending my entire computer to the shop for just the clock. 

My question: Is there a "standard" clock chip used in AT clones (just as the
8250 UART is commonly used for clone serial ports)? If so, how can I identify
this chip (i.e. what's the part number, how many pins does it have, etc.)
If I can find the chip, and it is socketed, I can just swap the chip out with
a new one.

If you can help, please email me at the address below. Thanks!


-- 
Scott Coleman 
 University of Illinois
  khan@ux1.cso.uiuc.edu

grege@gold.GVG.TEK.COM (Greg Ebert) (08/14/90)

In article <1990Aug13.180713.23645@ux1.cso.uiuc.edu> khan@ux1.cso.uiuc.edu (Scott Coleman) writes:
>I have a '386 AT Clone with a malfunctioning real-time clock chip. 

That beast is probably a Motorola 146818 CMOS clock/RAM chip, unless you have
a Chips & Technologies 82C206. The only other possibility would be a Dallas
module, which you DONT have because you have a battery.

You might want to poke-around with a voltmeter to see if the power-down
circuitry is working. Also, if your PC is UL approved, there are 2 series
diodes which might have poofed. Or your battery voltage is low. I've seen
6.8v and 4.5v batteries.