The lithium backup battery in the Dallas RTC chip has failed. You have two
Dallas chips in the 586. One is for the non-volatile RAM, the other is for
the time function.
Look on page 4-18 in your manual, it will show the two chips on figure
4-11. The DS 1287 package contains DS-1285 IC that has the backup battery
and the crystal piggybacked on top of it. The two devices are soldered to
the board. Replacements for the DS 1287 and for the DS 1220 non volatile
RAM chip are available from Ten Ted for $20.00 each. You might as well
replace both at the same time.
I added 24 pin IC sockets with machined pins when I replaced mine last
week. However, Ten Tec service advises AGAINST doing so.
I upgraded to the DS-12887 RTC, and it seemed to work okay. I also used a
150ns DS-1200 which also seems to be working... got both from Futurlec. I'd
advise getting the parts from Ten Tec. Do NOT use Chinese vendors on eBay.
The ones I bought from those clowns had dead batteries upon arrival. Must
have been very old stock. The batteries are good for about 10 years on
average.
Pete
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|